The UltraLite Kiln is the smallest kiln in the UK, and ideal for drying and firing Art Clay and PMC metal clays, enamelling, glass fusing, making jewellery, and keum-boo work. It's an 845°C, 250W, low-cost, compact, round kiln, with a lift-off lid.

The UK kiln is rated at 230V 250W, so can use a regular mains socket. It comes with a 30cm power cable and a regular UK plug, so you'll need an extension cable: as short as possible so there's no voltage drop.

However careful you are, kilns, torches, drills, files, knives, and chemicals, are 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 metal 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.

When firing, materials can flare up or explode, so wear safety glasses: you've only got one pair of eyes. If you work a lot with metal, glass, or beads, in a hot kiln, wear anti-glare glasses.
Drilling and filing release tiny bits of material that, given a chance, head straight for your eyes. Don't blow your work area clean: use a mini-vac.

Don't leave the kiln unattended. If you drop anything inside, let the kiln cool, and empty it out. It's very unlikely the kiln will need cleaning.

It's widely believed that the UK mains is 240V. Technically, it's been standardised throughout the EU at 230V +10% -6%, so it can vary quite a lot. However, if you measure your local voltage it's quite likely to be close to 240V.

One accurate long-term test showed a cycle occurring daily between Monday and Friday. The voltage at night rose to around 242V. During office hours, the voltage dropped to about 235V, probably due to manufacturing, transport, and offices increasing the load on the National Grid. During the weekend, the voltage was generally around 240V and did not show the daily fluctuations.

This means that the UltraLite will reach a maximum temperature which will depend on your local voltage. Interestingly, a drop of 3V reduces the wattage by about 2.5% and a rise of 3V increases the wattage by about 2.5%. So, it's important to test your firings carefully with small scraps of material.

Although the Ultra Lite Kiln has legs, it should stand on a ceramic tile or other heat-resistant surface to protect the worktop. Also, as the lid will be hot when you take it off, you'll need another tile to put the lid on.

Turn on the kiln and let it heat for 30 minutes with the cover off, and a further 15 minutes with the cover on. Generally, it will only need 45 minutes to reach the maximum temperature. A little faint smoke and a slight burning smell are normal.

Turn the kiln off, remove the lid, put a test piece of metal clay on the disk, put the lid back on, turn on the kiln, and fire it for about 30 minutes. It should go an orange-red.

THE CERAMIC INSERT

Place the ceramic disk in the kiln, textured side down, and pre-heat the kiln with the lid on for 35 minutes. Turn the kiln off, remove the lid, put a small test piece on the disk, turn on the kiln, and fire the metal clay for about 15 minutes to allow the binder to burn off. Then fire for another 15 minutes with the lid on.

Larger pieces will need firing on both sides, so turn your work over and repeat the firing. If you're using tweezers, wait until the work has cooled a bit. Before firing a second piece, put the lid on and let it heat for about 15 minutes.

You can try firing without the lid, with the lid off-centre, or with the lid on for some of the time: whatever works best. However, always check that the metal clay is still an orange-red. If the clay starts to shimmer, or show silver flashes or streaks, remove the lid as it's getting too hot.

As the maximum temperature should be about 845°C, there's little risk of over-firing your work as silver doesn't melt until 962°C.

Because the kiln heats from the bottom, you can't stack the discs. However, two extra discs allow you to put one on the lid to dry metal clays and use the other to lay out your next pieces for firing.

If your pieces are delicate or irregularly shaped, you could rest them on a thin ceramic-fibre cloth so they're supported during drying and firing. A thick cloth will act as an insulator.

Firing metal clay shaped around cork clay will inevitably produce flame, smoke, and a smell. As with fusing glass, experiment and paractise is the way to learn.

Glass can be put on the kiln's internal ceramic surface, on kiln paper to ensure a smooth finish. Put the lid on, turn on the kiln, and let it heat for about 35 minutes. You can look at the fusing progress through the opening.

When your piece is finished to your liking turn off the kiln. You may want to flash cool the kiln for a few seconds by lifting the lid and quickly replacing it, before letting the kiln cool to room temperature.

As with firing anything in any kiln, there's no definitive time-temperarture combination and, what works for a friend might not work for you. There's no substitute for learning by testing and from general experience.

KEUM-BOO COVERS

The red-brass covers are used for Keum-boo work. There are several excellent descriptions of Keum-boo on the internet so, rather than repeating them here, you need to research the subject. However, here's a brief description:

Keum-boo is a simple technique that bonds pure gold foil to another pure metal, such as fine silver, producing a rich gold colour. Because the gold foil is thin, the cost of adding pure gold to your work is low.

The gold is attached to the silver as a diffusion bond, an intermingling of molecules where the two metals meet. When pure metals are brought to the correct temperature, the molecules bond easily, when pressure is added, to create a permanent bond. This diffusion bond occurs far below the soldering temperature for either metal.

The kiln is hot enough if a lolly stick or cocktail stick chars in contact with the lid.

There are excellent descriptions of keum-boo on the internet so, rather than repeating them here, here's a brief introduction:

Newly-fired Art Clay and PMC are both pure silver, so don't need any surface preparation. Sterling silver must be depletion gilded by repeated heating and pickling before it can be used for keum-boo, to remove base metals from the alloy and leave a layer of pure metal on the surface.

The gold foil can be cut using a paper punch, a sharp modelling knife, or scissors. With scissors, it's often easier to cut the foil if it's between two thin pieces of paper.

Place it on the silver. If it drops off, pick it up with a damp finger or tweezers. After 25 minutes the kiln cover will be hot enough. Hold the piece still with tweezers and use a burnisher to press down the middle of the gold shape. Work outwards, smoothing the foil. The burnisher will heat up, so let it cool, or use a new one. You can re-heat the piece if an edge has not adhered.

When all the gold is in place, remove the piece from the lid and let it cool naturally. If you leave it on the kiln, the silver will continue to diffuse, and get paler.

Brush the piece with some soapy water, or use a little pumice powder. Tumbling generally creates a higher shine and the contrast between the silver and gold will diminish.

As with firing anything in any kiln, there's no definitive time-temperarture combination and, what works for a friend, might not work for you. There's no substitute for learning by testing and from general experience.

The photos show examples of gold leaf applied to Art Clay silver pendants. To look at the photos, hold your mouse over the appropriate zoom button below. The photos are 480px x 360px and about 94KB. If you're not on broadband, they'll take a short while to download.

Keum Boo Pendant.

Keum Boo Pendant.

The UltraLite is a very simple design, and unlikely to need servicing or repairing. If it doesn't heat up, there are only four possible causes: the mains socket isn't working, the fuse has failed, a wire has broken, or the element has burnt out.

To start, make sure the mains socket is working. If it is, take the plug apart, check the fuse, and confirm that the two wires are still connected and held firmly by the cable grip. If the kiln still doesn't work, the element will have burnt out. However, it's easy to fit a new one:

Before repairing your UltraLite for the first time, it's a good idea to make a drawing showing the position of the stand relative to the wire outlets. Then remove the central bolt that holds the whole kiln together. Whilst doing this, don't let the heating disc revolve as this may break the wires. The disc sits on three small removable ceramic supports, so be careful they don't fall out.

Carefully lift the heating disc out and check that both wires are connected. If they're not, they're not repairable. If they are, the element will have burnt out somewhere inside the ceramic disc.

Remove the plug, snip the nylon cable grip that clips the wires to the stand, and gently pull the wires out through the holes, again making sure that the three ceramic supports don't fall out.

Handle the new heating disc carefully as the element terminations are quite thin. Refit the three supports, the new heating disc, and the central bolt, making sure the disc doesn't revolve as you tighten it. Use the supplied cable grip to clip the wires to the stand as they were originally. Refit the plug, with one of the wires to live and the other to neutral. Check that the bolt is still tight.

To learn more about working with metal clays, buying and using kilns and tools, or choosing a course, look at The Art Clay Club, using the The Art Clay Club link above the menu bar.

The Art Clay Club is an information resource, not a shop, providing free on-line help, 24 7 52: you don't have to register, log on, or remember a password.

To buy Art Clay, and metal clay tools, transfer to The Kitiki Studio, using the Kitiki link above the menu bar. Alternatively, visit the Cherry Heaven Shop in Corfe Castle village.