Kiln Disaster & Melted a Days Work :(

I bought this Prometheus Pro 1 kiln at the Enamellers Guild Conference. I was quite excited about it (I'd been looking for a more transportable kiln and without vat this was a bargain!)
Above you can see the picture of it's first firing ~ with an empty chamber, just in case!. As some of you know I normally fire at 950 degrees, for 1 to 2 hours. This has worked fine in my Paragon SC2 ever since I got it (a number of years ago).....A jeweller friend of mine was round (we were doing some tube setting together) but as it was a brand new kiln I still checked the piece after about 20 minutes. At this point, looking through the little view hole, it was fine & pristine..... Another 20 minutes later and the piece was the puddle of molten fine silver you can see above.

We left the door open as the metal was literally hissing and bubbling...This picture was taken after the shock & "Oh my Gods" had died down and after I went and got my camera (and it's STILL molten).

Once it had cooled you can see why we were so worried - the metal had been melting it's way through the tile!!!

The supplier said that I should only fire at 800 and he wasn't suprised it melted. When I pointed out fine silvers melting point was higher than 950, the return answer was that was didn't matter as the instructions say to fire Art Clay at 800........but,

needless to say I'll now be firing at 899oC in my "big boy" and a little less in the Prometheus
Nic xx

P.S> If anyone knows how to get a lump of tile off a very melted 4 1/2 hours work please let me know....(and if you like the "Break The Rules" art then visit http://www.fredbabb.com/)

Perfect Torch for PMC & Soldering!

This is the Nimrod PT 500 Pro Torch, it's quite simply the best torch I've found for PMC and small scale jewellery soldering. Teresa Speer (head Honcho at the In the Studio Jewellery School) recommended it & I've been using mine for two years, for a large variety of jewellery tasks, without a single problem....

At approx £38 it certainly isn't the cheapest option, but it IS perhaps one of the best value:
1) It's solid construction, looks like it will last forever

2) It has a 60ml Butane reservoir so less refilling

3) Long Running Times - even when doing lots of work (up to an hour!)

4) Max torch temp 1350º C (2460º F)

It's also eminently adjustable and has done everything from firing PMC to fusing fine silver & melting dichroic glass too!

Top Torch Rating: 4.8 stars!
Ease of Use *****
Versatility *****
Construction *****
Price ****

If you haven't chosen your torch yet this is a great buy!
Nicola x

3 Kiln Comparison

There are lots of Kilns on the Market suitable for firing Precious Metal Clay. Here is a rundown on three of the most popular ~ the Kitiki Mini-Kiln, the Paragon SC-Series, and the Ultra-Lite kiln.

The Kitiki Mini-kiln is a good choice where kiln loads are likely to be small, or where space is an issue. It can be used for general low-budget small-scale work such as Art Clay, PMC, dichroic glass, enamelling, and jewellery.
If you are looking to buy a kiln for the first time, the Kitiki Mini-Kiln is a good choice for home, school, craft workshop, jewellery studio, or class. Besides being compact and easy to move, it uses a regular mains socket (no need for expensive re-wiring), it stays cool on the outside, it's controllable, it heats and cools quickly, and it's inexpensive to run.
Important Points
The Mini-Kiln has a Controller, not a Programmer, so there will be some limitations in available firing schedules. e.g. If the target temperature is low, and if the heating rate is set to full, the actual temperature will overshoot before the thermocouple and programmer can regulate it. If the target temperature is high, the overshoot will usually be negligible. While these variations don't affect Art Clay and PMC, they might affect glass, particularly dichroic glass.

The Mini-Kiln has a smaller firing chamber than larger kilns such as the SC2, so you can't stack it full of shelves with loads of pieces of jewellery: just four or five average things on the floor of the firing chamber, on a ceramic-fibre cloth or shelf. (i.e. Not big enough for large Bronze clay containers)

The Mini-Kiln heats to a lower top temperature – the top temperature of the Mini-Kiln is 1000°C, while the top temperature for the SC-2 is 1095°C. (This should not be an issue for PMC, Art Clay, dichroic glass or enamelling).

The Mini-Kiln door opens 90° so, unless the kiln has cooled completely, you should use long tongs in order not to burn your hand taking pieces out. The SC-2 door opens 180°.

Having said that it does have it's benefits too! It's more portable than an SC2 and cheaper too approx prices are currently £300-£350. :)

The Paragon SC series kilns The Paragon SC2 is a good first-kiln, popular with silver clay artists, particularly those also making jewellery with beads, dichroics, enamels, glass, and silver.
It's ideal for a studio running jewellery courses: it's compact and easy to move, it can use a regular mains socket, it stays cool on the outside, it's fully programmable, it heats and cools quickly, and it's inexpensive to run.

The Paragon SC series kilns come in two versions, as the SC-2 and the 50mm taller SC-3. Each version is made in the following four types: Basic, W with viewing window (shown), B with bead-annealing door, and BW with both door and window.
Firing CharacteristicsAll small, fast-heating, ceramic-fibre kilns, such as those in the SC series, with heating elements in both sides and the back, have firing characteristics you need to be aware of:
The actual temperature can overshoot before the thermocouple and programmer can regulate it: particularly if the heating rate is set to full. Set to a high temperature, the overshoot will usually be negligible.
Work placed at the back of the kiln will be slightly hotter than work at the front. Work near the sides of the kiln will be slightly hotter than work in the middle. If you're using several shelves, work on the top shelf will be slightly cooler.
The glass window in the SC2W, SC2BW, SC3W, and SC3BW, will modify the front-to-back temperature difference slightly. Also, at continual high temperatures, the window glass might discolour: but it's easy and cheap to replace. (You can also use the fibre plug when not enamelling etc to avoid this)

Apart from its internal size, the only minor limitation is that, although 1095°C is hot enough for low-fire ceramics, it's not hot enough for normal ceramics, porcelain, pottery, and stoneware: they need a 1260°C or 1290°C kiln.

My UK version SC-2 kiln has a sheathed thermocouple which helps prevent the possible corrosion, and eventual failure, of the bi-metallic tip: usually caused by pollutants produced whilst heating some types of glass.
The electronic display prompts for heating rate, target temperature, and hold time, making it easy to set up and re-use accurate drying, heating, holding, and cooling sequences.
Approx cost: £500-£600 (dependant on specification)

The UltraLite Kiln, is perfect for drying and firing your PMC, for enamelling, glass fusing, making jewellery, and keum-boo work. Please note that the Ultra Lite is not programmable - it's an 845°C, 250W, low-cost, compact, round kiln, with a lift-off lid

The UltraLite Kiln heats and cools quickly, but costs very little to run. It's ideal for small-scale work in your home, school, craft workshop, or jewellery studio, or at an arts centre running jewellery courses.
The UltraLite Kiln weighs just 1kg, so is easy to take to craft fairs, demonstrations, and exhibitions. If you already have a kiln, you can use an Ultra Lite for drying metal clays, firing single pieces, or quick tests. If you run courses, use several so that more experienced students can optimise their time, rather than wait for the slowest to catch up.

Firing Characteristics
The UltraLite is a small, fast-heating, ceramic-fibre kiln, with one embedded heating element in the bottom. Max temp is about 845°C. Putting the lid off-centre will effectively vent the kiln and reduce the temperature but, unless you use a pyrometer, you won't know what that temperature is.
It's ideal for firing Art Clay and PMC using the firing disc insert, and for keum-boo work using the red brass tops. At 845°C you can't over-fire silver clays as silver doesn't melt until about 962°C. You can work with dichroic glasses, enamels, and fused glass, but will need to experiment.
Keep a firing log: the material you used, the arrangement of pieces on the shelf, the firing cycle, and the end result. The log is useful if you're learning about colour, materials, temperature, and firing time, and a skilled artist will use the firing characteristics to advantage for different effects.

The only minor limitation is that, although 845°C is hot enough for silver metal-clays, it's not hot enough for gold metal-clays, ceramics, porcelain, pottery, and stoneware: they need a 1260°C or 1290°C kiln.

Approx cost: £180-£210 (dependant on specification, e.g. keum-boo plate & lid)

There are lots and lots of kilns out there, these are just a few of them (I have the SC2 with a viewing window) ~ if you have a different model and have found it fabulous and great value then please let us know about it in the comments box! :)

Hob Firing PMC and Art Clay Silver

FIRING on a GAS HOB
Ideally, SilverClay needs firing for a set time at a set temperature.
However, with practice, you can fire small pieces on a kitchen gas hob. This is best for pieces no bigger than a 50p piece and if you dont have a gas hob you could try a portable camping stove.

Lay the mesh on the hob and light the gas. As it heats up you'll notice cherry red areas these will be heating between 650-800 degrees (suitable for silver clay). Turn the gas off and, after the mesh has cooled, lay your dried clay on one of the red spots. Cover the piece with a mesh "box" for firing safety and relight the gas.

Fire your piece for 6-10 minutes, making sure that it's still in a red spot. Let it cool before you touch it, or the mesh. N.B If you don't get any red spots then your hobs flame may be too far from the mesh & the metal wont be strong enough if you try to fire this way... If you have a camping stove try that :)


Happy Heating x

Torch Firing PMC & Art Clay Silver

Torch Firing Process
(With thanks to Tim McCreight & his article in Studio PMC)
Allow the work to dry overnight or drive off moisture with a hairdryer, or in a slow oven. Make sure it's completely dry or the work can explode! Torch firing is not recommended for large items and you need good ventilation as you'll be close to the clay when the binder is burning off.
2. Place the work on a soldering block or fire brick, which is in turn set on either a fireproof surface or something you don’t mind being singed (like a piece of plywood). If you are working on the kitchen counter and the piece rolls off the block you don’t want to scar the countertop.
3. Light the torch and hold it so the flame is nearly vertical with the tip of the cone about 3/4" away from the work. Within a minute, the piece will be enveloped in a soft flame as the binder burns away. The flame will soon go out by itself. Within another minute, the piece will start to glow red. Continue heating until this becomes a bright and luminous color. At this point, glance at a clock.
4. Hold this color as uniformly as possible for about 5-7minutes. When the time is up, turn off the torch and allow the piece to cool. If you're not sure it's fully cooled use tongs or tweezers to pick it up and (providing it's not stone set) quench it in water.

A suggestion - Melt some Silverclay on Purpose
Most standard handheld torches are rated at 2000F so they can melt silver clay, in an effort to avoid this it's worth doing this experiment so you know what to look for.

Pull off a pea-sized bit of your chosen silver clay (PMC or ACS), split it in half, and roll out two small rods. Follow the instructions above with one added step. Concentrate the flame on one of the rods in an effort to melt it. You’ll see a bright mercury-like skin form on the piece and the red color will become even brighter. The edges will start to curl and the metal will be drawn up into a ball.
Make a mental note of what you saw. This way you’ll know the signs of melting, and you can withdraw the torch in time before damaging a piece you care about. To complete the experiment, allow the other rod to cool and test it by bending, filing, burnishing, and polishing. This will confirm that, sure enough, torch firing really works!