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Paragon SC2 Pro Jewellery And Enamelling Kiln With A Sentry Xpress Programmer. Nickel-Chromium K-Type Thermocouple. Electro-Mechanical Relay. Fire Bricks.

Over the years, we've been sent lots of ideas, suggestions, and tips. If you have anything to add that would help other kiln owners, use the mail link below the menu bar near the top-right of any page. But please keep your suggestions general in nature rather than about specific materials or processes.


Before we look at specifics, I'll begin with a section about how your kiln works and what you can do to check for possible faults. After that, skim through the sections and read those that interest you. If you want to ask anything, mail or call.

SYSTEMATIC FAULT FINDING
Paragon Vulcan Kiln.

How Does A Kiln Work?

If it's your first kiln, you might feel apprehensive about turning on something that will get red hot. However, a kiln, even a large one, isn't a very complicated thing, so there's no reason to be anxious about using it: it's little more than a big toaster. And, because it's made of metal, firebricks, and ceramic fibre, it won't just burst into flames.

It's just an insulated box with an electronic programmer and some red-hot elements. Inside, there's something called a thermocouple that measures the temperature and something else called a relay which is just a big switch. The thermocouple talks to the programmer, and the programmer talks to the relay telling it to turn the elements on or off. The programmer is similar to the one that controls your central heating: although it's a lot simpler to set up.

As with most electronic things, the programmer is a low-voltage device so there's no mains just behind the buttons. And, like every electrical thing with a metal case, the whole thing is earthed so that, in the very very unlikely event of a serious fault, either the plug fuse or the mains fuse in the fuse box will pop.


When the kiln is switched on, the display usually shows 8888. This checks that all four digits, and all the parts that make up the digits, are working.

After a few seconds, the display will show the programmer version and configuration number: something like E-1 or F-1. If it shows PF, there was a power failure during the last attempted firing. It probably means that you turned the kiln off in the middle of a programme, not that there was a complete electrical failure. To clear this, press Start/Stop.

After a few more seconds the display will alternate between IDLE and the current room temperature. If the temperature looks very wrong, the thermocouple has probably failed. Remember that the thermocouple is in a red-hot kiln and will eventually corrode: it won't last for ever.

If the kiln is at room temperature, reach inside and squeeze the thermocouple tip gently. The display should show the temperature increasing to around normal skin temperature.


Set a programme: full speed to 600°C then hold for three minutes. Start the programme, stay by the kiln, and write down what happens. After a few seconds the relay, an electro-mechanical switch, will click, the elements will come on, and the temperature will start to increase. The thermocouple checks the temperature and, depending on the sequence you've chosen, the programmer turns the elements on or off to control the heating rate, the target temperature, and, eventually, the cooling rate. When the sequence is complete, the kiln beeps.

If there's a second click almost straight away, or the displayed temperature doesn't increase, the relay is probably faulty and isn't staying on: so the elements can't heat up. It's less likely that the elements have burnt out, but we'll look at this later.

Because the programmer was set to heat up at full speed, the relay should stay on until around 600°C. Then it will click off and the hold time will begin. It will probably click on and off a few more times to keep the temperature more or less constant. After the hold time has expired, it will click once more, the relay will be off, the elements will be off, and the sequence will have completed. You can turn the kiln off if you wish, unless you want to watch the temperature fall.

If the sequence completed, the kiln would appear to be working correctly. If it kept rising well above the 600°C, the thermocouple might be faulty and not reporting the correct temperature to the programmer. Or the relay has stuck on. However, relays sticking on is rare: they usually don't stay on.


Further checks need to be done by someone who has a multi-meter, similar to the one described below, and is confident about working with mains voltages. You can buy a multi-meter in the on-line shop. If you're only half confident, call one of our engineers when you have the multimeter and you're by the kiln.

Although these notes apply to a Paragon SC2, the procedures are similar for other models. Unplug the kiln, stand it on a blanket so that nothing gets scratched, remove the back, lower it down, and do a visual check that all the wires are connected and there are no signs of sparking or burning.

In the factory, the casing screws are put in tightly with an electric screwdriver. When removing them, use the correct-size screwdriver. As with any screw, the wrong size screwdriver can damage the head, making it difficult to remove. You might need some pliers just to ease the loosened screws out.

Identify the two thin wires, red and yellow, that conect the thermocouple to the programmer, and the two thick wires that come from the relay and go to the elements. There are usually brass connectors joining the thick wires to the element ends.

Set the multimeter for resistance, probably a 200 ohms setting, and measure the resistance of the elements. Do this carefully as there may be two elements joined together. The reading will be 7 - 35 ohms, depending on the kiln. If the multi-meter says zero, the element has failed.

The next part is done with the kiln on, so needs extra care. Unplug the kiln, set the multimeter for AC voltage, probably a 500 volt setting, and tape the leads onto the brass connectors on the element ends. Plug in the kiln, and start the programme we used above. As soon as the relay clicks, the meter should show mains voltage, around 240V in the UK, and the kiln should start to heat up. If it shows zero, the relay is not switching on: even if you heard it click.

Switch the kiln off, unplug it, and un-tape the multimeter leads. It's very important to be careful with the leads as, if one end is touching a live voltage, the other mustn't touch the metal case, other components, or you.


Remove the screws holding the programmer in place, and gently ease it out of the metalwork. All the connectors should be firmly on, especially the thin red and yellow thermocouple wires that are held in push-down connectors. Check that they're not loose or touching each other.


Many kilns have more than one element, and some have more than one relay. If you can run a programme, open the door and the lid briefly and make sure that all the elements are glowing. If one or more aren't, the kiln probably won't reach the temperature you've set.


So, the most likely problems will be that the thermocouple has failed, then the relay, then the element. You can talk to a technician, although basic checks, adjustments, and repairs are quick and easy, needing little more than a PoziDriv screwdriver. You can watch on-line service videos: use the watch-videos link below the menu bar near the top of the page, then choose from the guide.

GENERAL SAFETY
Medical Care.

Safety And Public Liability.

However careful you are, kilns, torches, drills, files, knives, and chemicals, are all potentially dangerous. If there's an accident, you won't have time to find out what to do, so think about safety issues before you start work. Generally:

If you're working with electric kilns, gas hobs, and butane torches, there's always a risk that you'll have an accident with hot materials or set fire to something.
It's important to have a fire extinguisher, nearby. Read the instructions as soon as you unpack it, learn how to treat burns, buy a basic first aid kit, and fit a smoke alarm. However, don't position the smoke alarm over the kiln.

If you're using cutting, drilling, or abrasive tools, wear safety glasses: you've only got one pair of eyes. If you work with hot metal, glass, beads, or ceramics, wear glare-resistant glasses and heat-resistant gloves.

For accessories, options, and tools, such as extinguishers, safety glass, hot glasses, and hot gloves, use the shop link below the menu bar near the top-right of every page.

THE KILN WORK AREA

The Kiln Work Area.

Kilns need to be in an open, well ventilated space, not in a cupboard or closet. They should be at least 300mm from any vertical surface that could burn, and, if you have two kilns, at least 500mm apart. Never put insulation around a kiln to try to conserve energy: the wiring and the programmer will overheat, and may burn out.

Table-top kilns either don't need a stand or come with 50mm high rails. Most kilns have plastic non-slip feet so don't need to stand on anything else. Although, if the worktop is easily marked put the kiln on a rectangle of wood.

If your kiln comes with a floor stand, don't abandon it and put the kiln on a flat surface as this will prevent the natural flow of air around the kiln and change it's firing characteristics. If it comes with a vent, this needs to connect to the outide: not another room.

Small kilns, such as the SC series, can use a regular mains socket and stand on a worktop or table, Large kilns, such as the Janus 27, need a dedicated circuit, and should stand on the floor: a floor not a carpet.

If you stand your kiln on a table with castors or wheels, you need to wedge the wheels or use a wheel lock. Otherwise, if you knock the table, your work may fall over.

If the room is protected by a fire-prevention sprinkler system, don't position the kiln under a sprinkler or a heat sensor: the whole system might come on and flood the building. Ask about getting a smoke sensor instead of a heat sensor.

Make certain that no one can touch the kiln who doesn't understand what a kiln is and the sort of temperatures used during firing. If inexperienced people are around, make sure they understand that the kiln might be hot. Opening the door mid-sequence will cause a sudden drop in temperature: glass pieces may crack.

Although kilns have automatic digital programmers and built-in safety cut-outs, don't leave your kiln on if you leave the house or go to bed.

If you're using your kiln in a garden shed or a garage, check that you don't have paints, volatile inflammable solvents, petrol, a lawnmower, or a car, in the same space. And ventilate the area.


If you use your kiln at home, check your building and contents insurance: a standard policy may not cover you against an accident arising from using a kiln, especially if it's used by a business.

If you're running courses at your home or workplace, you may need public liability insurance. And check that you have complied with local health and safety regulations and change-of-use planning consent. These might include providing protective eyeware, fire extinguishers, first-aid training, disabled access, a bathroom, and fire exits.

VOLTS, AMPS, AND WATTS
A Domestic Consumer Unit.

Electricity.

If you avoided a technical education, there are three commonly-used electrical measurements: Volts, for example 230V, is the pushing force. Amps, for example 5A, is the amount being pushed. Watts, for example 60W, is the energy.

They're related by a simple formula: Watts = Volts x Amps, usually written W = VI. A 240V 13A socket can deliver 240 x 13 Watts, or 3120W, usually written as 3.12kW where a kiloWatt is a thousand Watts.

As an example, the Paragon SC-2 1680W kiln uses less power than a 2kW convector heater. So, you can plug it into a regular socket. It costs about 16p/hour to run, whilst heating up at the fastest rate, but less normally as the relay cuts in and out.


It's interesting that a 10W radio will fill the room, a 100W light bulb will light the room, but a 1000W fan heater will barely warm the room. So, as we pay for electricity by the kilowatt, it's heating devices that cost the most to run. Which is why you get a big bill if you leave the immersion heater on.
Sadly, riding an excercise bike can only generate about 70W so, although the exercise keeps you warm, it's hard to be energy-independent. Especially as most of a light bulb's energy is heat rather than light.


Most domestic and small-business buildings have a main fusebox, or consumer unit. Different fuses restrict the amount of current that can be drawn by function groups, such as the lights on one floor, the power sockets on one floor, the kitchen sockets, ovens and grills, a shower and pump, or a garage and outside lights. If you exceed a fuse's rating, it pops.

To supply lights, the fusebox uses several ring mains, each ring separately fused and rated at 5A or about 1200W. Typically, a ring main starts at the fusebox, visits several wall switches and lights in different rooms on the same floor, and returns to the fusebox. The whole circuit is earthed at the fusebox. A lighting circuit is not designed to power heating devices.

To supply power sockets, the fusebox uses several ring mains, each ring separately fused and rated at 30A or about 7000W. Typically, a ring main starts at the fusebox, visits several double sockets in different rooms on the same floor, and returns to the fusebox. The whole circuit is earthed at the fusebox. A double socket accepts two 13A plugs.

To generalise, you can't plug lots of heating devices into all the sockets: neither the fuse nor the cable will survive, although the fuse should pop before the cable burns out. Although fuses are easy to reset or cheap to replace, replacing burnt-out wiring is difficult and expensive.

In older properties, several owners with varying levels of skill, may have changed the circuit or extended it. It's quite common for a ring main, to have a spur to another socket or even to another room. So, take care.


For accessories, options, and tools, such as mains-testing screwdrivers and multimeters, use the shop link below the menu bar near the top-right of every page.

THE POWER SUPPLY
UK 3-PIN 13A Plug.

The Power Supply.

The smaller kilns have a 13A UK three-pin plug: so they're ready to go. The larger kilns need to be wired in: they don't use a plug.

As you can see in the diagram, the live, the brown wire, connects to a 13A fuse. The neutral, the blue wire, connects to the neutral pin. And the earth, a green-yellow wire, connects to the earth pin.

In the event of an electrical fault. there are six levels of protection. A small fuse, part of the kiln, protects the programmer. The 13A plug fuse protects the equipment. The metal casing is earthed. The fusebox fuse, typically 30A, protects the whole circuit. The fusebox usually has a separate earth-leak fuse. And the building has a fuse, typically 100A for a small house, to protect the whole electrical installation.

In addition, plugs have plastic insulation on the live and neutral pins so that you can't accidentally touch them whilst pushing the plug in or pulling it out, and the plug socket has an internal shield which only slides out of the way when the earth pin goes in.


The smaller kilns, up to 3120W, can use a regular mains socket. The 1095°C 3120W Xpress E-14A is the largest kiln, internally in volume, that can use a regular 230V mains socket. Above that, you'll need a dedicated power supply, 30A, 45A, 65A, or 75A, straight from the main fusebox.

SAFETY CUT-OFF SWITCHES

Cut-Off Switches.

US-made kilns often have live heating elements that are exposed whenever the door or lid is open. So, to comply with EU safety regulations, an additional switch, included in the price, is fitted to cut off the power to the elements when the kiln is opened. Exposed live elements are very dangerous, and illegal in the UK. So, there's no chance of turning on the kiln, putting some work in, and getting a shock. However, always take extra care.

The nature of safety switches is that they're not big 60A switches, but low current switches that turn off the main relay or relays. This technique is common in industrial equipment.

DELIVERY TOUCH DOWN
Delivery By Air.

National And International Delivery.

Usually, the very popular SC series kilns are in stock, ready for delivery to your nominated address. All the larger kilns are made to order, take about 20 working days to build, about four working days to ship, and will arrive in a box, in a crate, or on a palette.

Paragon in the US makes around 400 different models, many of which are available in seven colours or have modifications, so doesn't have a warehouse full of ready-to-ship kilns. Although Cherry Heaven is an EU distributor and service centre, it's not feasible to showcase the extensive range, especially as most kilns are protectively boxed, crated, or palleted for local delivery or international shipping.

Kilns regularly leave the US factory for the UK using reserved air cargo to minimise the freight charges. Air cargo typically takes four days. Sea freight takes at least three weeks: or longer, as resellers often secure advance payments then wait to collect enough orders to fill a container.


If you call first, you can collect one of the smaller kilns from Cherry Heaven in West Holme village. However, a larger kiln, such as a crated Fusion 10, weighs 106kg and is 1300mm across, so it won't fit in a regular car.


Your kiln will usually be delivered by one of the well-known shipping companies, such as Chase Freight, City Link, Concordia, DHL, Fedex, Parcel Force, TNT, or UPS. When you sign for it, write unexamined by your signature. If there's any damage, take photos, don't touch the packing, and call the shipping company.

DAMAGE AND REPAIRS
Kiln Damage. Kiln Damage. Kiln Damage. Kiln Damage.

The Paragon SC2 and Xpress E12A in our studio have run perfectly for years. However, eventually, all elements corrode and become less efficient, thermocouples become less accurate, relays stick or won't hold on, and, very rarely, electronic programmers develop a fault. So, although Paragon kilns are robust and rarely need attention, you do need to think about what will happen if you damage your kiln or it goes wrong.

The photos above show how some users have been careless: they've spilt moulten glass, fired materials that exploded, broken the ceramic fibre with bead rods, or put a cover over the kiln to insulate it.

WHAT HAPPENS NEXT

Should anything go wrong, call or mail first. If you call, and we're too busy to answer, make sure you leave your phone number and a good time for us to call you.

Whilst you're near your kiln, an engineer will talk you through a few tests to try to narrow down the problem. It's a good way to learn more about your kiln, and it might save replacing two parts when you only need to replace one.

Cherry Heaven provides on-line television programmes about servicing and repair. So, once you know which bit has to be replaced, watch the appropriate video: use the watch-videos link below the menu bar at the top of the page.

SELF-SERVICE
Paragon SC-2 Door Hinge.

A kiln is a fairly simple piece of equipment. The mains electricity comes in, via a fuse, to the main switch, then splits and goes to a transformer and a relay, or set of relays.

The transformer reduces the voltage for the programmer. The programme tells the relays when to turn on and off. The relays act as switches, turning the elements on and off. The programmer makes it's decisions using the set programme and the thermocouple's feedback.

Replacing the programmer only involves a few screws and some push-fit connectors. Replacing the thermocouple, the relay, or the elements, is straightforward, but you need to take the kiln apart. Anyone practical and careful can repair their kiln.


If the programmer doesn't light up, check the mains fuse and the kiln fuse. If either fuse has failed, and a replacement fails, there's probably a short circuit inside the programmer case.

If you feel that you can test and repair your kiln, disconnect it before opening the case. Look for spark marks or any wires that have come loose. Once disconnected, the thermocouple and elements can be tested for continuity.

Make a sketch of the inside, ot take a clear photo, before you start. As you remove the bits, lay them out in sequence so that you don't re-assemble the kiln only to find that a part was left out.

Make sure that screwdrivers are the right size and won't damage the heads. Be careful with self-tapping screws: if they go back in at an angle, they may strip the thread from the hole. If this happens, buy some slightly larger screws. Use spanners, not pliers, for nuts.

Remember that dust acts like an insulator on electronic parts, and could cause them to overheat. Blow the dust away: don't use a brush as you could generate static electricity and damage the controller chip.

BUYING SPARE PARTS

Most spares can be ordered on line. However, as Paragon makes over 400 models, we can't keep every part for every kiln in stock all the time. Although we try to order out-of-stock parts promptly, there may be a manufacturer's delay, a public holiday, an import document discrepancy, a trainee delivery driver, traffic chaos, or some other complication. We can only do our very best.


Most retailers and distributors say they can get spare parts. This often means that they'll be ordered for inclusion with the next shipment. Unless imports arrive regularly, it may take four weeks to get them and, unless they have repair facilities and use competent in-house engineers, you could lose the use of your kiln for six weeks.

Consequently, owners sometimes chose to return them to the US for service or repair. However, the very expensive two-way shipping charges and the overall down-time were still a serious setback for a small business.


Within the UK, Cherry Heaven will accept your kiln for service or repair. However, it will need to be re-packed safely so, before you unpack your new kiln, remember how it was packed or crated, keep the original packing, and take a photo.

If you don't have the original packing, find something that can be re-used for the return journey as we don't have any empty boxes, crates, or palettes. You don't need to return manuals, shelves, mandrel holders, or any other accessories. To learn more, mail or call.

Servicing and repairs are done here, in Dorset, by experienced engineers. You can deliver the kiln yourself, or use your freight company account. Or we can have it collected. Address it to:

Cherry Heaven  


Although we service and repair kilns here, it may be easier for us to send you the parts and for a local engineer to do the work, avoiding the two-way shipping charges and the delay.

TEMPERATURE
Temperature.

Temperature.

A kiln's maximum operating temperature sets limits on the materials and processes you can use. 1290°C is the highest temperature that standard kilns reach: above that, the materials and construction have to change, and the cost increases dramatically.

Porcelain and stoneware need about 1290°C, jewellery and low-fire ceramics about 1095°C, glass casting, fusing, sagging, and slumping about 925°C, and annealing about 650°C.

The maximum temperature is not related to the wattage: so a 4800W kiln does not get twice as hot as a 2400W kiln. The temperature depends on the elements, the firing chamber volume, the insulation, and the programmer.

As with any device you buy, a kiln is not designed to be run full-on all the time. So, if you need to fire at 925°C for a long time, buy a 1095°C kiln, not a 925°C kiln. To give you a feel for temperature, here are the melting points for a few common materials:


MATERIAL °C
aluminium 659
copper 1083
glass 1700
gold 1063
lead 163
nickel 1452
platinum 1772
silver 962
steel 1371
tungsten 3399

I sometimes get asked if there's a platinum metal clay: there is, but it's an industrial product. Platinum melts at 1772°C, so a platimum clay would probably need to fire at around 1600°C: beyond the maximum temperature of conventional kilns.

CENTIGRADE AND FAHRENHEIT

The three main temperature scales are Celsius, Fahrenheit, and Kelvin. The metric system, used in the EU and most other countries, uses the Celsius scale. The everyday descriptions are:

In the Celsius temperature scale, pure water freezes at 0°C and boils at 100°C. Celsius is the international standard, having replaced the equivalent Centigrade in 1948.

In the Fahrenheit temperature scale, it freezes at 32°F and boils at 212°F. Fahrenheit is commonly used in the US, and sometimes conversationally in the UK.

In the Kelvin temperature scale, it freezes at 273.15K and boils at 373.15K. Kelvin is not measured in degrees Kelvin, just Kelvin: so it's written K, not °K.

In the Kelvin scale, absolute zero is the hypothetical, but unattainable, temperature at which matter exhibits zero entropy. It's defined as being precisely 0K or -273.15°C. Celsius and Kelvin are used in scientific work.

To convert Celsius to Fahreneit, multiply by 9, divide by 5, and add 32. To convert Fahrenheit to Celsius, subtract 32, divide by 9, and multiply by 5.

KILN FURNITURE: A GENERAL INTRODUCTION IMPORTANT
Paragon Kiln Shelf Kit. Paragon Rectangular Kiln Shelves. Paragon Round Kiln Shelves. Paragon Mixed Kiln Shelves.

Kiln Furniture: Rectangular, Round, Hexagonal, and Octagonal Shelves, And Posts.

Most kilns have a recommended furniture kit. Delivery companies have a low rate for parcels less than 30kg so, for smaller kilns weighing less than 30Kg, the kit is generally one shelf and four posts: included in the price because it fits in the box and doesn't add much to the overall weight.

You get a professional, durable, cordierite shelf with four 12mm high posts. You don't get a soft, ceramic-fibre shelf, often described as free, that will gradually break up and need replacing.

Shelf kits for rectangular or square kilns usually include four 25mm x 25mm x 12mm shelf posts, When flat, they're 12mm high: on their sides, they're 25mm. Other sizes, up to 150mm high, are available, so you can choose the shelf spacing that suits your kiln and your work. Shelves for cylindrical kilns usually have three posts.

The recommended kit is usually the simplest that works: not an expensive collection that I've put together for you. However, extra shelf kits allow you to stack your work, optimising your use of the firing chamber volume, the unit-cost of firing, and your time. And extra half-shelves or smaller shelves allow you to fire a mix of shorter and taller pieces.


For larger kilns weighing more than 30Kg, shelf kits are not included in the price because you'll probably want to choose your own mix of shelves, half-shelves, smaller shelves, and assorted-height posts.


One shelf should stay on the floor of the firing chamber all the time in case you accidentally spill or melt anything: solidified glass or metal is impossible to pick off without damaging the ceramic-fibre or firebrick.

Shelves are not meant to be an exact fit in the kiln. You need finger space all round and they mustn't scrape the kiln walls every time they're put in or taken out. Be careful lifting heavy shelves out of a top-opening kiln: if you drop them they will damage the firebricks.

Although they look tough, most ceramics break if they're dropped on a hard floor, so it's a good idea to have spare shelves, especially if your business depends on your kiln or you're running courses.


During firing sequences with heating, holding, and cooling segments, the elements turn on and off repeatedly. In a small kiln, with little residual heat, the inevitable temperature changes can make glass crack as it expands and contracts. A thick heavy shelf stores heat and, because it's resting on posts, the air circulates, helping to even out the normal temperature fluctuations.


If you're buying your first kiln, you're probably interested in one material, such as silver clay, or one process, such as enamelling. However, after a few successes, and failures, most people want to try different materials, make larger pieces, experiment with combinations, fire more at a time, and soon become interested in something else: or everything else. Some start a business or run classes.

You might want a full shelf, two half-shelves, several mixed shelves, a set of shelf posts, a bead-mandrel holder, glass separator, hot gloves, kiln wash, a knife-making rack, pyrometric cones, a tile holder, or other accessories.

Shelves are heavy, so kits ordered separately need a box and protective packing and attract an extra delivery charge. Outside the UK mainland, this might be expensive. So, if you think you'll need them, order them with your kiln, along with any other accessories, materials, parts, or tools.


For dichroics, enamelling, and glass fusing, put kiln paper on the shelf to stop the glass sticking: it's simpler and cleaner to use than glass separator. Bullseye Thinfire shelf paper, probably the most popular, ensures easy separation between your glass and the kiln shelf. One side feels slightly smoother than the other: that's the glass side.

Generally, glasswork needs radiant heat and will fuse, sag, or slump better on one shelf than between closely stacked shelves, although experienced glass artists often use several shelves successfully.

Delicate pieces can be fired on a puffed-up ceramic-fibre cloth: on a shelf. Round pieces, that could roll to one side, can be fired on a hollowed-out ceramic-fibre block. However, if the kin has elements in the bottom as with the Mini-Kiln and Prometheus Pro-7, a cloth or block will act as insulator and the kiln might overheat.

Particulates represent a health risk if they're breathed in, so wear a HEPA mask when cleaning out your kiln, mixing kiln wash, and working with ceramic-fibre blocks, ceramic cloths, and papers. And, ideally, use protective glasses.

If you want to touch anything hot, or move your kiln before it's cooled off, it's important to wear heat-resistant gloves. And, if you want to look into a red-hot kiln, even briefly, wear glare-resistant glasses to protect your eyes from IR and UV.


If your day-to-day work depends on your kiln and down-time will be disruptive or expensive, it's a good idea to have spares: extra shelves, a selection of posts, elements, a relay, and a thermocouple.

You can learn about ceramic blocks and cloths, charcoal, dust masks, glare-resistant glasses, glass separator, heat-resistant gloves, kiln vents, kiln wash, programmers, protective glasses, USB interfaces, shelf paper, tools, and other accessories, using the accessories link below the menu bar near the top of the front page. And they're all in the on-line shop.


Shelves are checked before despatch and are wrapped protectively. But they're not guaranteed and we cannot be responsible for any later damage.

Normally, pieces are put into the kiln on a shelf. When they've been fired, the shelf is taken out and put on ceramic fibre blocks, in a tray of vermiculite, or on some other heat-resistant surface, to cool. A kitchen tile is not thick enough: the heat will go through and might burn the work surface.

USING KILN FURNITURE

Kiln Furniture.

Never fire anything on the exposed floor of the firing chamber. If moulten metal, glass, or enamel sticks to the ceramic fibre or firebrick, it will be very difficult to remove without causing damage, particularly as glaze or enamelling drips can be asbsorbed into the ceramic fibre and then ruin the element. Shelves, and shelf paper, are designed to prevent this happening.

Shelves are made of cordierite. However, it's brittle so, if you drop the shelf, it might break. Although shelves can be repaired, it's not worth the risk as, if they break again, it will be just as you put your delicate unfired pieces in the kiln. It's a good idea to have spare shelves, especially if your business depends on your kiln.
Shelf posts are made of the same material. Some people use three, as there's no chance of the shelf rocking: although four minimises the risk of the shelf tipping if you put a heavy piece off-centre.

If you've washed a shelf, or it's got wet, you'll need to dry it before firing, or the water will turn to steam and the pressure increase may crack or shatter the shelf. It's unlikely, but it could explode, so wear safety glasses.

Although shelves last a long time, the continual expansion and contraction will cause surface cracks: this is normal. Providing a shelf doesn't look as though it will break, you can carry on using it.


Most furniture kits include 25mm x 25mm x 12mm posts. They can be used flat to lift the shelf 12mm, or on their edges to lift the shelf 25mm. When you use four on their edges, put two north-south and two east-west so that the shelf doesn't wobble over.


If you break a shelf, you may still be able to use the pieces, on posts, for smaller work. If you buy a tile-cutting saw, you can make a regular-shaped shelf from an irregular piece.


For accessories, options, and tools, such as kiln shelves and posts, use the shop link below the menu bar near the top-right of every page.

CERAMIC FIBRE CLOTHS
Ceramic Fibre Cloths.

Ceramic Fibre Cloths.

Fibre cloths are used to support delicate pieces in the kiln, either as a flat surface or cut into pieces. The cloths in the on-line shop are about 200mm x 150mm x 25mm although they can be cut to size easily with scissors


For accessories, options, and tools, such as ceramic fibre coths, use the shop link below the menu bar near the top-right of every page.

CERAMIC FIBRE BLOCKS
Ceramic Blocks.

Ceramic Blocks.

If you've just dried or fired Art Clay or PMC, you need to take out the hot shelf and put it somewhere safe. Ceramic blocks are ideal.

Be careful if you use any other materials: plastic will melt, wood will burn, glass will shatter, a tile will crack, a firebrick is brittle and heavy, and welders' squares and plumbers' mats are too thin. On a kitchen worktop, the wood will burn or the laminate will discolour and lift. Metal will just conduct the heat to the surface it's resting on.

If you're firing anything small and rounded, be careful that it doesn't roll off and break or burn something. The ceramic fibre block is very soft, so you could make a slight hollow on one side. However, if you fire two things, make sure they don't roll together and touch.

The heat-resistant block in the on-line shop is made from light ceramic. Unlike a heavy rough-cast fire brick, it won't scratch the work top if you move it about.


For accessories, options, and tools, such as ceramic blocks, use the shop link below the menu bar near the top-right of every page.

VERMICULITE
Vermiculite.

Vermiculite.

Vermiculite is used to support delicate work in your kiln or, spread in a tray, to act as a soft heat-resistant surface when you take things out of the kiln. It'll last a long time, although it will eventually break up.

The vermiculite in the photo is expanded hydrated phlogopite mica: the particles are very light, non-toxic, and won't fuse until at least 1200°C, about 2200°F.

If you use a tray of vermiculite, keep it covered when it's not in use, to prevent stray materials mixing and getting stuck to your work. Also, vermiculite particles are very light and can jump onto your clothes if your movement generates static electricity, or blow everywhere if there's a window open.


It's not easy to find vermiculite in the high street as it might have plant food or polystyrene particles mixed in: so be careful.

The Kitiki vermiculite comes in a white plastic screw-top pot for convenience and safety: not a plastic bag, and not a pot that can't be closed properly once the seal has been broken.

Although it's filled to the brim during packing, particles settle and it may not look quite full when you open it. It's plainly much easier to fill a pot with a fixed volume than to measure out a fixed weight every time.


For accessories, options, and tools, such as vermiculite, use the shop link below the menu bar near the top-right of every page.

KILN PAPER
Ceramic Fibre Paper.

Kiln Paper.

Kiln paper, often called shelf paper, consists of compressed ceramic fibres held together with a binder. It looks like normal thick paper, and can be cut to size easily with scissors. As with any fibrous material, don't get the fibres on your hands or breathe them in.

During firing, the room should be vented as the burning binder may smell and release a little smoke. Usually, the paper burns away, leaving a little dust: so clean out the kiln regularly.

The paper in the on-line shop comes as single sheets, each one 520mm x 520mm square, or as a pack of four. Although kiln paper is much simpler, cleaner, and quicker to use than kiln wash, it does cost more. And it doesn't protect the shelf against ceramic glazes which would just soak through.


For accessories, options, and tools, such as kiln paper, use the shop link below the menu bar near the top-right of every page.

GLASS SEPARATOR

Kiln Wash.

If a glaze or hot glass sticks to the kiln shelf, it's very difficult to remove without pulling away part of the shelf surface. To protect the shelf and make separation easy, you need to brush on a coat of glass separator or use a protective layer of kiln paper.

Glass separator, often called kiln wash, consists of finely ground minerals that don't fuse at normal firing temperatures. It prevents glass and glazes sticking to the shelf. It's mixed with water and painted on using a soft-bristle haik brush. Usually, several thin coats are applied in different directions.

A few tips: don't use glass separator on ceramic fibre; don't get the powder on your hands or breathe it in; stir the mixture every time you dip the brush in; and store it in a glass jar.

You need to dry the shelf before firing, or the water will turn to steam and the sudden pressure increase may crack or shatter the shelf. It's unlikely, but it could explode, so always wear safety glasses when you open your kiln.

You can let it dry naturally in a warm place overnight, put it on a central heating radiator, or stand it on kiln posts and heat it, with the kiln vent open, at 150°C for 30 minutes.


Generally, glass separator will last for several firings: the lower the temperature, the longer it lasts. However, most users re-coat before firing. Before applying another layer, smooth the shelf surface with some wet+dry paper. For most small pieces, kiln paper is easier to use.

Kiln wash should never be applied to the lid, door, or walls of the kiln, and it's especially important to keep it away from the elements.

PROGRAMMERS  0:0:0
Orton-Paragon Sentry Xpress Controller.

Programmers.

Most modern kilns use an electronic programmer, or digital controller, such as the Orton Sentry. A programmer allows you to set up accurate drying, heating, holding, and cooling sequences: and do something else whilst the sequence is running. The programmers are easy to use, and the sequences can be saved for the future.

Paragon kilns don't have programmers with pre-set sequences: you can choose the sequence temperatures, times, and heating and cooling rates.
As a beginner, pre-sets may seem to be an advantage. However, having experimented, many people fire materials, or combinations of materials, at different temperatures and for different times than are recommended.
And, later, you might want to work with other processes and materials such as: china painting, dichroic glass, dolls, enamels, fusing, glass-bead annealing, glazes, gold paints, low-fire ceramics, sagging, and slumping.

The programmer is partly controlled by a temperature-sensing thermocouple. However, kilns on full heat will overshoot the set temperature briefly before settling back. Using the kiln for low-temperature processes, such as baking Fimo Polymer Clay, needs care.
The effects of this overshoot can largely be prevented by setting a lower temperature or a lower heating rate. Usually, this has no effect on your work, but keeping a kiln log will help you learn how to set temperatures.


Paragon kilns usually use the 3-key Sentry Xpress 4.0 or the 12-key Sentry 2.0 digital programmer, both developed by Paragon and the Orton Ceramic Foundation. To learn more about programmers, use the programmers link below the menu bar near the top of the page.

A programmer, or digital controller, allows you to set up, and re-use, accurate drying, heating, holding, and cooling sequences: and do something else whilst the sequence is running. A sequence can consist of up to eight segments.
A segment is one step in a sequence: often the time it takes to reach a target temperature. For example: one segment could take 50 minutes to reach 650°C; another could hold at 850°C for 12 minutes; and another could take 90 minutes to cool down.

Paragon kilns don't have programmers with pre-set sequences: you can choose the sequence temperatures, times, and heating and cooling rates.
As a beginner, pre-sets may seem to be an advantage. However, having experimented, many people fire materials, or combinations of materials, at different temperatures and for different times than are recommended.
And, later, you might want to work with other processes and materials such as: china painting, dichroic glass, dolls, enamels, fusing, glass-bead annealing, glazes, gold paints, low-fire ceramics, sagging, and slumping.


The programmer is partly controlled by a temperature-sensing thermocouple. However, kilns on full heat will overshoot the set temperature briefly before settling back. Using the kiln for low-temperature processes, such as baking Fimo Polymer Clay, needs care.
The effects of this overshoot can largely be prevented by setting a lower temperature or a lower heating rate. Usually, this has no effect on your work, but keeping a kiln log, described below, will help you learn how to set temperatures.


Most programmers have a temperature alarm that you can set. Here are a few reasons why the alarm will sound, or why you will want to use it:

List. the temperature was set to lower than room temperature
List. if you've propped the lid open, use the alarm as a reminder
List. if you've set a temperature, use the alarm as a reminder
List. if you need to look through the window, use the alarm as a reminder
List. if you want to turn the kiln off manually, use the alarm as a reminder

To turn off the alarm, press any key except STOP. All the functions of the alarm will be described in the appropriate programmer's manual.


The kiln's maximum cooling rate, even with the lid or door open, depends on the type of kiln. If it takes four hours to cool from 650°C to 100°C, the programmer can't speed this up, even if you program a full cooling rate. The purpose of controlled cooling is to make the kiln cool down slower than it would if you turned it off and allowed it to cool on its own.

KILN TIMER
Digital Timer.

Using A Digital Timer.

Although most kilns come with programmers, it's very easy to walk off and forget. A digital kiln-timer, is something you take with you to remind you that time's up.

It's particularly useful when using the Kitiki Mini-Kiln which, although it has a programmable maximum temperature, doesn't turn itself off. The Kitiki Timer, in the on-line shop, can be set to beep at any time up to 100 minutes: just set the minutes and seconds, and start the timer. It measures 86mm x 47mm x 16mm.

KEEP A KILN LOG

Kiln Log.

The best way to learn about your kiln is to keep a firing log, listing the material you used, the shelves and their spacing, the firing cycle, and the end result. The log is vital if you're experimenting with dichroic glasses, enamels, glazes, and other colour-dependent materials.

Also, if you're firing the kiln for the first time for several months, you can review your logbook to regain a quick feel for what to try.

FIRST USE

First Firing.

Most heating devices smell when used for the first few times, so use the kiln in a well-ventilated room. The stainless steel casing, or the paint, may eventually discolour, particularly around the door.

As the ceramic chamber or firebricks expand and contract with use, small cracks may appear. These are normal and harmless, and will not affect the firing.

Relays used with digital programmers click as the elements are turned on and off to control the heating or cooling rate, or keep a steady temperature. If you're working with other people, tell them that the clicking is normal: otherwise they might think it's a fault and turn the kiln off.

Elements can be destroyed by contact with silica and silica compounds, and by reduction firing: so read the notes that come with your kiln.

Inside the firing chamber, a heat-sensitive thermocouple, connected to the programmer, projects into the firing space. If you accidently push it back, it can't give accurate readings and the kiln will overheat. Although the programmer provides error messages to report problems, it won't warn you about this.

Firing Art Clay can leave very faint traces of silver in the pores of the ceramic firing chamber. This may affect the colour of some glasses, so always do a colour test first.

If you're stacking several shelves or firing pieces that nearly fill the firing chamber, make sure that there's 25mm clear space around the thermocouple, or it won't be able to read the temperature acurately.

TEMPERATURE STABILITY

Temperature Stability.

Small ceramic-fibre kilns, such as those in the SC series, heat very quickly. Although the thermocouple checks the interior temperature every four or five seconds, the walls of the kiln containing the elements will be hotter and will still radiate heat for a short while after the element is turned off. Also, the programmer averages out the changes rather than trying to turn the elements on or off every few seconds.

On the fastest heating rate, with the elements on the whole time, the temperature will overshoot the set temperature, possibly by as much as 6-7%. If this adversely affects your work, set a slower heating rate.

Our programmers have an important refinement. When they turn the elements off at, for example, 700°C, residual heat will continue to increase the temperature briefly. A small kiln can overshoot to 715°C before falling back down. A software modification slows down the heating rate just before the target temperature, reducing any overshoot and improving the accuracy.

OPENING THE DOOR OR LID DURING FIRING

Firing.

Generally, opening the door or lid of a hot kiln won't damage the firebricks. However, most manufacturers recommend that you wait until you can unload pieces bare-handed before opening the lid of the kiln to prevent damage to your work, rather than to the kiln. For example, if you remove glass too soon, it may crack as it cools.

Most electric kilns are made with K-23 firebricks, which have a low alumina content: K-25 bricks have a higher alumina content. Low-alumina firebricks can withstand dramatic temperature changes without cracking.

You can open a hot kiln to remove raku pieces, open the lid to rake or emboss the surface of softened glass, or open ceramic fibre kilns, such as the SC-2, at 900°C, to remove silver clay.

Rapid firing won't harm your kiln, either. The K-23 bricks and ceramic fibre are less susceptible to cracking from rapid firing than any clay you will ever place inside the kiln.

KEEPING THE KILN CLEAN

Cleaning The Kiln.

One reader sent in this: The kilns were near the clean-up area where the worker brushed off the mould marks and sanded down large greenware pieces. He'd then blow off the dust with a compressed air gun, all the time unmasked.

Clay contains silica. Dry clay contains free silica. Silica in the lungs causes silicosis. Silicosis causes illness and premature death. Always work in a well-ventilated area and wear a HEPA dust mask. Always clean up your work area regularly.


With top-opening glass kilns, tiny particles can sometimes drop onto the glass. Vacuum the kiln regularly. Alternatively, if it's a ceramic fibre lid, brush a coat of rigidiser onto the fibre.

The fibre absorbs the rigidizer much like a sponge, so you will need to dab it on rather than brush it. It only needs only one application. The ceramic fibre surface should be dry to the touch before firing the kiln but, the first time you fire after applying rigidizer, hold the kiln at 120°C for 20 minutes.

HOW TO USE A DIGITAL MUTIMETER
Kitiki Digital Multimeter.

How To Use A Digital MultiMeter.

A multimeter lets you test electrical equipment. Using the two leads, you can typically measure continuity, DC voltage, AC voltage, DC current, AC current, and resistance. The photo is of a typical multimeter, although the ones in stock may not be quite the same.

Most multimeters are broadly the same. You usually set the range using a central dial. The most important thing is not to let the leads touch anything other than the contact points you're testing.

The Kitiki MultiMeter is ideal for checking and repairing your kiln. You can check the mains voltage, the plug fuse, the kiln fuse, the transfomer, the relay, and the elements.


A multimeter is a useful tool. You can test batteries, bulbs, cables, christmas lights, doorbells, fuses, power adapters, relays, switches, and wires, as well check most domestic electrical equipment.

Some multimeters can check diodes and transistors, measure temperature, measure frequency, and hold the displayed result after you've taken the leads off.

SOLDERING IRON
Kitiki Soldering Iron.

Kitiki Soldering Iron.

Soldering is a convenient way of joining metals. The Kitiki soldering iron is rated at 230V 60W and can also be used for general electrical and electronic work. It comes with enough solder to get you started. However, it might not be the colour shown.

The Kitiki Soldering Iron is a multi-purpose soldering iron. Having experimented, there's a wide choice of soldering irons and solders, depending on what you want to do.

CUTTERS AND PLIERS
Kitiki Pliers And Cutters.

Kitiki Cutters And Pliers.

Cutters and pliers are some of the most useful tools when you make jewellery, work with electronic parts, build dolls' furniture, or enjoy model engineering.

These Kitiki cutters and pliers successfully combine materials, size, precision, alignment, hardness, sharpness, and ergonomics. They're about 120mm long, easy to use, comfortable to hold, and beautifully made.

You'll enjoy using good tools rather than continually improvising. They'll help you manage a creative and efficient work environment. And they'll last a long time.

The pliers and cutters shown in the photo above are the six most popular. Although, in theory, the pliers partly share their uses, in practice, one is just easier to use for one task, and one for another.

Kitiki cutters are used to cut wire, strips, chains, and clasp links. The cutting edges are hardened and align perfectly, and the cut is slightly oblique or vee-shaped.

Kitiki flush cutters are used to cut wire, strips, chains, and clasp links. The cutting edges are hardened and align perfectly, and the cut is nearly straight.

Kitiki flat-nose pliers have tapered rectangular jaws, and are used to position and adjust jewellery findings, squeeze and close links, straighten wire, bend wire and strips at angles, and shape paper-type metal clays.

Kitiki pointed-nose pliers have tapered semi-circular jaws, and are used to shape jewellery findings, re-shape links, and bend wire and strips into curves, circles, and ovals.

Kitiki bent-nose pliers sometimes called pointed-nose, have tapered semi-circular jaws, and are used to shape jewellery findings, re-shape links, and bend wire and strips into curves, circles, and ovals.

Kitiki round-nose pliers have tapered circular jaws, and are used to position and adjust jewellery findings, squeeze and close links, bend wire and strips at angles, and shape paper-type metal clays.

To look at the pop-up photos, hold your mouse over the zoom buttons below: you don't need to click.


Kitiki Cutters. Kitiki Cutters .

Kitiki Flush Cutters. Kitiki Flush Cutters.

Kitiki Flat-Nose Pliers. Kitiki Flat-Nose Pliers.

Kitiki Pointed-Nose Pliers. Kitiki Pointed-Nose Pliers.

Kitiki Bent-Nose Pliers. Kitiki Bent-Nose Pliers.

Kitiki Round-Nose Pliers. Kitiki Round-Nose Pliers.


Before dismissing the word ergonomic, remember that the palm of your hand has around 1700 nerve endings and, every time you hold a hand tool, 42 muscles are put to work. The continual strain of using an awkward tool makes delicate work less accurate and more difficult, and can lead to strain injury or numbness.

Designing and making precision hand tools that work smoothly and accurately, and feel comfortable, is a complicated, expensive, precision process. So, here are some general comments:


Very few shops sell high quality pliers and cutters for delicate work: most pliers and cutters are designed to undo rusted nuts and cut fence wire.

Economy pliers and cutters usually use regular mild steel, inadequately hardened, and laquered to hide the poor finish. The laquer will soon wear away and the metal will rust or stain. They're often rebranded, repackaged, and repriced, with different coloured handles: so it's hard to know what you're getting.

Economy special-offer boxed sets appear to be good value. However, once opened and used, the poor quality will soon become apparent. Buying like this is unpredictable and replacing one of the set, or buying a different shape, is usually impossible as the brand will have disappeared.

Poorly machined, aligned, and hardened cutting edges will cut at an angle or unevenly, and will soon go blunt or get notched. Poorly machined and aligned jaws will make it diificult to hold small shapes reliably.

Jaws might have high spots, serrations, or roughly finished edges that will mark soft metals such as silver, copper, and gold. Jewellery pliers have smooth jaws, and are precision engineered for careful work.

If they're uncomfortable to hold, the handles can nip your skin whilst squeezing, and the sprung release-action might need too much continual pressure: tiring during precision work. Tight hinges won't release unless you use both hands.

Some jewellery and electronic pliers have very short handles and are quite difficult for an adult to hold. Work soon becomes tiring: that's when you make mistakes.

Scissor-style hinges, rather than box-style hinges, will gradually loosen and twist as you bend and cut, making delicate work less accurate and more difficult.


Jewellery cutters are not designed to cut spring steel or stainless steel wire or strips. If you want to work with these, or other hard materials, you need special snips: mail or call.


The internet is packed full with inaccuracies: accidental or intentional. There are unsubstantiated claims that whatever is being sold is the best, the newest, or the cheapest, and it's being sold by the largest dealer or the premier distributor.

So, why buy Kitiki cutters and pliers from Cherry Heaven?

We used to sell Swedish-made Lindstrom cutters and pliers. They were generally agreed to be the best you could buy, and Lindstrom promoted the box-joint designs as the best solution. However, they were very expensive, varying in price from about £40 to £75 depending where you shopped.

When the factory moved to Spain, many people felt that the quality wasn't as good, especially as they now used the scissor-joint. So, we had our own made in the same factory that makes our magnetic polishers, small kilns, and other tools. They cost about five or six times less.

FIRE EXTINGUISHER

Kitiki Fire Extinguisher.

Kitiki Fire Extinguisher.

If you're working with kilns, you need to be aware of the risks, however slight. It's important to have a fire extinguisher, nearby. Read the instructions as soon as you unpack it, buy a basic first aid kit, learn how to treat burns, and fit a smoke alarm.

The fire extinguisher is rated for electrical fires. It contains sodium bicarbonate, a dry chemical that's non-toxic, helps prevent re-ignition, and doesn't soak soft furnishings. It comes with a wall bracket so it can be mounted conveniently.

Although it's very unlikely that you'll have an accident, it's important to take basic safety precautions when working with liquids, powders, resins, sharp tools, and hot kilns: especially if you do demonstrations or run classes. And remember, never get careless: kilns are very hot and connected to the mains.

GLARE-RESISTANT SAFETY GLASSES

Kitiki Glare-Resistant Glasses.

Kitiki Glare-Resistant Glasses.

If you look at hot materials in a kiln, through a peephole or by opening the bead door, door, or lid, it's important to wear tinted glasses. The Kitiki glare-resistant glasses are coated to filter the harmful infra-red and ultra-violet light emitted by kilns. Keep them by your kiln and get used to putting them on every time.

The glare-resistant glasses have amber lenses, fit over prescription glasses, and can be cleaned with warm soapy water. They have non-slip nose pads, weigh just 26gms, and come with a micro-fibre pouch. They're virtually identical to sun glasses that retail at around £70, so you can wear them on the beach.

They exceed the EN 166 Impact Resistance and EN 172 Full Solar and UV standards which define the design, construction, testing, and use of eye protection devices.

Although the lenses are made from tough impact-resistant polycarbonate plastic and the frame from nylon, the glasses aren't unbreakable and the lenses aren't scratch proof: so look after them.

HEAT-RESISTANT SAFETY GLOVES

Kitiki Heat-Resistant Safety Gloves.

Kitiki Heat-Resistant Safety Gloves.

Heat-resistant gloves are made from a special non-woven polyester with a nitrile outer coating and a felt inner. They're rated to 180°C, so are ideal for moving kilns and lifting out shelves or hot work without waiting until everything has cooled completely. They're not fire-proof.

The gloves are one size but, like oven gloves, are easy to work with. Wash them at 60°C and dry them in a warm place: don't use dry-cleaning solvents.

HEPA DUST MASK

3M HEPA Dust Mask.

3M HEPA Dust Mask.

All particulates represent a health risk, however minor. It's important to wear a HEPA mask when cleaning out your kiln, mixing or using powders, handling charcoals, and drilling, filing, and sanding metal and glass clays, especially at a course venue. And, ideally, use protective eyewear.

The 3M Advanced Electret Mask is a professional three-panel valved design which combines mechanical and electrostatic fibres: it's not just a piece of cloth on elastic.

A unique one-way valve makes it easier to breath out, so the mask feels cooler and drier. It uses thinner material that that used in most respirators, so the mask shape feels soft and secure. They're individually wrapped to keep them clean, and use no natural rubber compounds.

PROTECTIVE GLASSES

Kitiki Protective Safety Glasses.

Kitiki Protective Safety Glasses.

You probably use abrasives, some drills, an engraver, a grinder, a set of files, a hammer, polishes, a few wire brushes, and other small hand tools. This is just the time that a tiny glass or metal fragment will get in your eyes. And, although it's unlikely, some materials could flare up or explode, so wear safety glasses when you open the lid or the door: you've only got one pair of eyes.

The Kitiki protective glasses have clear lenses, will fit over regular glasses, and can be cleaned with warm soapy water. They conform to the ANSI Z87.1-2003 standard which defines the design, construction, testing, and use of eye protection devices, including impact and penetration resistance.

Although they're made from impact-resistant polycarbonate plastic, they're not unbreakable and the lenses are not scratch proof: so look after them.

THERMOCOUPLES
Paragon PY70 Thermocouple. Paragon PY54 Thermocouple. Paragon PY81 Thermocouple. Paragon PY54 Back Plate.

Thermocouples On Paragon Kilns.

Kilns measure the firing chamber temperature using a thermocouple. Gradually, thermocouples drift with age but, since they're not expensive, it's a good idea to order a spare when you buy the kiln. If there is a failure, you'll only have a few hours down-time, rather than a few days.

When thermocouples fail, the temperature display often becomes erratic or very inaccurate. Occasionally, problems can be caused by a loose thermocouple connection or a bare spot on the thermocouple wire touching the kiln case.


The oldest thermocouple is a bead-style PY70 K-type, as in the first photo: it looks like two wires joined by a dot-weld. The wires pass through three ceramic sleeves and are long enough to reach the programmer board. The exposed bead can fail eventually because of everyday oxidation, corrosive gases, or prolonged high-temperature firing.

This was replaced by a stainless-steel sheathed-style PY54 K-type, as in the second photo, mounted on a ceramic back-plate held in place by two screws. The sheathed bead can fail eventually because of heat degradation, corrosive gases, or epoxy breakdown inside the sheath.

The new thermocouple is a heavy-guage welded PY84 K-type, as in the third photo, mounted on a ceramic back-plate held in place by two screws. It's a long-life design that responds more quickly to temperature changes and minimises the risk of corrosion and subsequent failure of the bi-metallic tip.
It's a universal design so it fits all the Paragon kilns. If the one you're replacing is shorter, carefully break off the last ceramic sleeve with some pliers. Partly straighten the wires, without breaking another sleeve, and fit the thermocouple. The wires will now be too long so nip off the excess so they don't touch the back of the kiln when it's all re-assembled. Don't do this before you fit it or you won't know which is the red connection.


To replace the newer styles, the ceramic back plate, inside the kiln, needs to be removed. It very rarely needs replacing, so a new thermocouple doesn't need a new back plate. When refitting the back plate, take great care not to over-tighten the retaining screws as the ceramic might crack.

The two wires, red and yellow, fit into two colour-coded push-down connectors on the programmer board. Make sure that the wires are gripped well, don't touch each other, and can't touch the metal case.

The K-type thermocouple, used in most of the Paragon kilns, has a nickel-chromium and nickel-aluminium bead. As an example, this pairing generates 12.2mV at 300°C. If accuracy, long-life, reliability, and stability are vital, especially at temperatures above 1100°C, you can upgrade to an S-type platinum-rhodium thermocouple. This has a porcelain tube.


Don't work on your kiln on any surface that might get scratched. Unplug the kiln. In the factory, screws are put in tightly with an electric screwdriver. When removing them, use the correct-size screwdriver. As with any screw, the wrong size screwdriver can damage the head, making it difficult to remove. And, when refitting them, don't over-tighten them in case the thread strips.


For accessories, options, and tools, such as K-Type and S-TYpe thermocouples, use the shop link below the menu bar near the top-right of every page.

REPAIRING HEATING ELEMENTS
Paragon Element. Paragon Element.

Repairing Elements.

The short answer is don't. However, some users have repaired burned-out elements by twisting the broken ends together with pliers and heating the two ends to bright-red heat with a small gas torch.

This rarely works for long because the element develops a protective oxide coating after many firings. The coating not only protects the wire from further oxidation, but it's also a good electrical insulator, so the connection made by twisting is electrically poor. The poor connection will not conduct current very well, locally over-heat during firing, and probably burn out again.

On very rare occasions if you're lucky, the wire gets just hot enough during firing to part-weld itself together without melting, making a good connection. However, usually, the twisted joint burns out near the end of the firing when the kiln is at its hottest: so the user gets just one more firing out of the element.


In the unlikely event of an element failing, elements laying in firebricks are inexpensive and easy to replace. Elements embedded in ceramic fibre can't be replaced: you'll need to replace the ceramic-fibre liner.


For accessories, options, and tools, such as relays and elements, use the shop link below the menu bar near the top-right of every page.

FIRING CHARACTERISTICS

How Electric Kilns Work.

Generally, as soon as a programmable kiln starts its firing sequence, it begins to heat up at a rate set by the programmer. It can't heat up quicker than it would do with the elements full on all the time.

The thermocouple tells the programmer the current internal temperature and, depending on the sequence you've chosen, the programmer turns the elements on or off to control the sequence segments: the heating rate, the target temperature, the hold time, and the cooling rate. It can't cool down quicker than it would do with the kiln turned off. When the sequence is complete, the kiln beeps, and the sequence stops.


For safety, the programmer doesn't switch the full mains voltage. Instead it drives a relay, an electro-mechanical switch. The programmer uses a low voltage to activate the switch which turns the high-voltage high-current elements on or off.


When the target temperature is reached, the programmer switches the elements off. However, residual heat in the firing chamber allows the internal temperature to overshoot the target temperature briefly before starting to fall back.

This overshoot is more evident at low temperatures than at high temperatures, and in small kilns rather than large kilns. For example: 300°C will probably overshoot to 350°C whereas 800°C will probably only overshoot to 805°C before starting to fall back.

However, our Sentry Xpress programmers have a software modification that slows down the heating just before the target temperature, reducing any overshoot and improving the accuracy.

During the hold-time, with the elements still off, the temperature starts to fall. When the programmer switches the elements back on, the firing chamber will initially absorb some of the new heat before the temperature recovers. The continual switching of the elements on and off causes the internal temperature to oscillate either side of the target temperature.

This is similar to central heating. If you set it for 21°C, it probably oscillates, quite slowly, around 20°C to 22°C: and you won't notice. The accuracy will depend on where the thermostat is sited, how quickly it responds, how accurate it is, how long it takes for the radiators to heat up, and if you have doors and windows open. The temperature will probably be different in each room.

So, regardless of the thermocouple temperature, the actual temperature of your work will be slightly different, depending on its position on the kiln shelf, the vertical spacing of any stacked shelves, and its nearness to the elements, a lid, a door, a bead door, or a window. Learn to take this into account if you're working with temperature-critical materials or processes.


Remember that glass needs radiant heat and will fuse, sag, or slump better on one shelf at the bottom than between closely stacked shelves.


Kiln doors and lids are not meant to be a perfect fit otherwise, at high temperatures, there'd be no room for expansion and movement, and the door could stick and the ceramic-fibre or firebricks could crack.

All kilns smell a bit, and even produce whisps of smoke, during the first firings, just like a toaster or a fan heater. If you're worried about fumes, open a window.

Eventually, with normal use, kilns discolour slightly, inside and outside, and some firebricks might develop hairline cracks. Your kiln is a versatile, robust, red-hot tool: not an ornament.

KEEPING A KILN LOG

Keeping A Kiln Log.

Using your kiln successfully needs critical research and frequent tests, especially as things that work for your friends and teachers might not work in the same way for you. It's also very important to learn how to creatively use unexpected effects. So, keep a firing log:


Buy a durable notebook. Use a new page for every firing, and draw diagrams of the shelves, their vertical spacing, and the position of your work on the shelves. Along with your work, put a few scraps at different places on the shelves to learn how things change. Describe the material, the shape of your work, the firing cycle, and the end result. Add a few photos and sketches, and mark the page corners with coloured dots or symbols as a quick reminder of your success rating.

A kiln log is vital if you're experimenting with temperature-sensitive materials or working with metals, coloured dichroic glasses, enamels, glazes, or china paints, and a skilled artist will use the kiln log to advantage to re-create effects. It'll be particularly useful if you have to repeat a commission, or you have a long holiday before returning to your studio.


Some Paragon kilns have a Sentry 12-key or a Sentinel Touch Screen programmer which can be connected to your computer through a factory-fitted USB interface. The Control Master software allows you to control and monitor the firing, and analyse, arrange, save, and print out the data. If you want this feature, make sure you order the USB interface in the on-line shop.

FIRING CERAMICS, PORCELAIN, POTTERY, AND STONEWARE

Firing Ceramics.

Before it's fired, unfired clay, or greenware, needs to be dried to evaporate the water: just like Art Clay and PMC. If you don't dry it completely, the water will turn to steam during firing and the pressure increase might crack or shatter the clay. It's unlikely, but it could explode, so wear safety glasses when you open the kiln.

The most expensive way to dry ware is to heat it in a kiln. The moisture in the clay rusts the kiln, wears out elements faster, and wastes electricity.

After firing ceramics, leave your work in the kiln to cool naturally. If you take it out too soon, it may crack from thermal shock. Never fire tempered glass as it could explode.

When you fire your pieces, use some of the empty shelf space to fire small test materials and shapes. It's a good way to learn.

PYROMETRIC CONES

Pyrometric Cones.

If you work with Art Clay, PMC, or glass, you'll understand how the ramp-hold Orton Sentry programmer works. However, if you want to work with ceramics, you may prefer to use pyrometric cones.

Pyrometric cones are slender pyramids, made from about 100 carefully controlled compositions, that measure the effect of time and temperature. As the cone nears its maturing range, it softens and the tip begins to bend down under it's own weight. Ceramics are usually sold with firing instructions, which include the cone number.

Cone-Fire, generally used for ceramics, pottery, stoneware, glazes, china painting, and decals, fires to a set pyrometric cone number listed in the Orton cone tables. It's not designed for Art Clay, enameling, glass work, or heat treating.
Cone-Fire will only be successful if you understand how cones and cone numbers work. Unlike a programmer, a cone is a visual indicator that your work has been fired for the correct combination of kiln temperature, kiln atmosphere, and time.


If you bought a ceramics kiln with a cone-fire-enabled programmer, you can fire without using cones because the programmer is set up to use cone numbers. If you have a ramp-hold programmer, you'll need to be able to convert cone numbers to temperature and time. Of course, you can't use a cone that matures at a higher temperature than your kiln can maintain.

Cone numbers were originally set from 1 to 10, 1 being the coolest. However, cooler cones were introduced from 022 to 01. To fire faster or slower than the segments listed, change the rates by 10 - 20%. However, the last segment should always be 108.

WORKING WITH GLAZES

Glazes.

At high temperatures, glazes will stick to anything. Always put your work on a protective shelf, not on the exposed firing chamber floor.

Some glazes may release toxic chemicals into food or drink. Make sure that you use an approved and tested product, applied and fired as recommended.

FIREBRICKS
Firebricks. Elements. Firebrick Butt Joint. Hardened Meeting Surfaces.

Firebricks.

Kiln bricks, also called fire bricks or refractory bricks, are made from high-temperature ceramic. Typically, bricks are good insulators and are used to line the inside of the kiln, minimising heat loss and reducing energy use.

Kiln bricks can be cut or moulded into different shapes and sizes, as hard bricks or soft bricks. Hard bricks are strong and dense, can withstand extreme temperatures, are largely unaffected by gases in the kiln, and are generally used for structural support. Soft bricks are less dense, are excellent insulators, and are generally used for insulation.

Kiln manufacturers usually use a small range of shapes and sizes assembled in different arrangements. Sometimes, as in a kiln lid, they're cemented together but, as in a kiln body, they're arranged in sections or stacked layers making it easy to replace any damaged ones. The elements in Paragon kilns are in dropped recessed grooves, so don't need retaining pins.

Although butt joints are the simplest, they're not the strongest, so lapped and notched joints are used, as in the third photo. For durability, the meeting edges of a lid and body are hardened with refractory cement, as in the fourth photo.


Kiln firebricks, unlike home-hearth firebricks, are not as hard as they look and can sometimes shed fine dust in the firing chamber. It's important to vacuum out any dust. However, be very careful with the vacuum cleaner brush-cup and don't knock or scrape the bricks, particularly along the edges of the element grooves.

Kiln doors and lids are not meant to be a perfect fit otherwise, at high temperatures, there'd be no room for expansion and the door could stick and the ceramic-fibre or firebricks could crack. So, a thin line of light around parts of the door or lid is normal.

Eventually, with normal use, kilns discolour slightly, inside and outside, and some firebricks might develop hairline cracks, although they'll close up at high temperatures. Remember, your kiln is a robust, versatile, red-hot tool: not an ornament.

The bottom of a firebrick kiln needs a coat of kiln wash: one that's rated to 1290°C. Don't get any kiln wash on the elements or the sides of the kiln.


It won't do any harm to the firebricks to open the door slightly for a few seconds to check work in progress. If you look at hot materials in a kiln regularly, either through a peephole or by opening the lid or door, wear tinted glare-resistant glasses. You can buy hot glasses in the on-line shop.

Paragon sells replacement bricks for all their models. To order these, mail me a photo, and the name, part number, and serial number of the kiln. Please note: Sentry Xpress, Sentry, and Sentinel are the names of the programmers, not the kilns.


For accessories, options, and tools, such as kiln wash and hot glasses, use the shop link below the menu bar near the top-right of every page.

SECOND-HAND KILNS

It's worth adding that, to help prevent you becoming someone's legal prey, buying a second-hand kiln has risks: you don't know if the elements have been over-fired and might soon fail, the programmer may have an intermittent fault, the relays may be sticky, the thermocouple might not be accurate, it could have been poorly repaired, you'll have no guarantee, and, if it does fail quickly, the seller won't take it back.

Paragon Kilns, Furnaces, and Ovens For Annealing, Beads, Ceramics, Enamels, Glass, Jewellery, Knife Making, Lost Wax, Silver Clays, Heat Treating, Lampwork, Porcelain, And Vitrigraph.


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UK To EU Plug Adapter.
Ceramic Block.
Ceramic Cloth.
EU Plug.
UK-EU Adapter.
Dry Powder Extinguisher.
Glare Resistant Glasses.
HEPA Mask.
heat-resistant Gloves.
Kitiki Cutters.
Kitiki Flush Cutters.
Kitiki Flat-Nose Pliers.
Kitiki Pointed-Nose Pliers.
Kitiki Bent-Nose Pliers.
Kitiki Round-Nose Pliers.
Protective Glasses.
Potter & Brumfield Relay.
Dorset, SW England.
UK 13A Plug.
The AX-4 Digital Controller.
MiniKiln Closed.
Prometheus Pro-7.
Large Rubber Drum 950gm Open
Bartlett-Paragon Touch Screen Digital Controller.
Paragon BlueBird Bead Annealing Kiln.
Lauscha by Carrie Fertig.
Activated Charcoal Granules.
Paragon Caldera Ceramics Kiln.
Paragon Caldera Bead Kiln.
Paragon Fusion CS14D Glass Kiln.
Paragon Fusion CS14SB Glass And Bead Kiln.
Paragon Caldera XL Ceramics Kiln.
Paragon F500 Lampwork Kiln.
Paragon FireFly Ceramics Kiln.
Paragon Fusion 7 Glass Kiln.
Paragon Fusion 8 Glass Kiln.
Paragon GL18ADTSD Glass Kiln.
Paragon HT-14D Heat Treating Furnace.
Paragon Janus 1613 Ceramics Kiln.
Paragon KM18D Knife Making Oven.
Paragon-Orton Vent Master: Unassembled.
Paragon-Orton Vent Master: Suction Cup.
Paragon Pearl 18 Glass Kiln.
Paragon PMT21 Heat Treating Kiln.
Paragon Door Peephole And Vent.
Stainless Steel Pans.
Paragon SC-2 Black Jewellery Kiln.
Paragon SC2 Jewellery Kiln.
Paragon SC2B Bead-Door Kiln.
Paragon SC2W Enamelling Kiln.
Paragon SC4 Glass Kiln.
Paragon SC2BW Jewellery And Bead Kiln.
Paragon SC2D Pro-3 Jewellery Kiln.
Paragon SC2 Shelf Kit.
Paragon SC-2 Jade Jewellery Kiln.
Paragon SC-2 Black Jewellery Kiln.
Orton-Paragon Sentry Xpress Programmer.
Orton-Paragon Sentry Programmer.
Bartlett-Paragon Sentinel Touch-Screen Controller.
Paragon SC-2 Pink Jewellery Kiln.
Paragon SC-2 Pro Black Jewellery Kiln.
Paragon SC-2 Turqoise Jewellery Kiln.
Paragon SC-2 Purple Jewellery Kiln.
Paragon SC-2 Navy Jewellery Kiln.
Paragon SC-2 Berry Jewellery Kiln.
Paragon ST-8 Kiln Table.
Paragon ST-8 Kiln Table With Casters.
Paragon TNF 1613 Ceramics Kiln.
Paragon GL24 Kiln Table.
Paragon Xpress 1613 Top Row Of Bricks.
Paragon W Lost-Wax Casting Kiln.
Paragon Lost-Wax Burnout Tray.
USB Plug.
Paragon Xpress E-12 Jewellery Kiln.
Paragon Xpress E-12B Bead Kiln.
Paragon Xpress E-14 Glass Kiln.
Paragon Xpress Q-11 Ceramics Kiln.