Firing precious metal clay
You can fire fine silver metal clay at home without a kiln. Just use a simple torch, gas hob, or camping stove.
Firing precious metal clay like Art Clay Fine Silver is really easy as fine silver clay sinter (=becomes solid silver) successfully at a very wide range of temperatures. Art Clay Fine Silver will sinter successfully between 650°C - 900°C. So your firing temperature can vary up and down 250°C, and the silver will still fire fine (as long as you have fired for long enough).
This wide range of firing temperature is what allows fine silver clay to be fired with a torch or gas stove - and what makes it very different to base metal clays and sterling silver clay, like Art Clay Silver Sterling 950 Clay - these are best fired in a kiln as that gives you more control. Most base metal clays (not all) usually have a very narrow window of safe firing temperatures, for some base metal clays even a teeny 30°C change can be the difference between success and failure.
Here you can download and print detailed instructions for;
TORCH FIRING - CLICK HERE FOR PRINTABLE INSTRUCTIONS
Torch firing is a great, inexpensive, way to fire your precious metal clay. Just keep your smaller than a £2 coin, and weighing under 25gm.
You will need a small butane gas torch, like a kitchen torch, and heat proof surface, like a ceramic fibre brick to fire on. Here is a great torch kit, which will save you some money.
TORCH FIRING DIRECTIONS
- Familiarise yourself with the temperature colour chart below, and set a timer with the required firing time, ready to just press start.
- Read the instructions that come with the torch before you begin. Your torch will require cigarette lighter butane GAS (not the liquid you use with a Zippo lighter). Fill your lighter in short increments - have a look here for a video with some tips.
- Ensure your clay is FULLY dry. Place the dry piece on a ceramic fibre firing brick.
- Dim the lights in the room to help you see the glow during firing. The colour is how you tell what temperature your silver is.
- Switch on the torch and direct the flame at a 45° angle at a distance from your silver of about 5-10 centimetres. The distance will vary depending on the torch you are using and the size of the piece. It is VERY important to hold your torch at a 45° angle to one side of the piece. NEVER hold your torch right above the piece you are firing, this will reflect a lot of heat back from the silver to the tip of your torch, and may damage your torch (and the guarantee will not cover a melted tip).
- Move the flame around the piece to heat it evenly. Move it slowly (you're not in a rush!) in a figure of 8 so you're sure you're heating the whole piece evenly. Even heat across the whole piece is important to ensure a full sinter, and to avoid any uneven shrinkage.
- You will see a little smoke and flame as the non-toxic organic binder burns away. Keep firing.
- When the piece begins to glow peach (see the colour chart to the below), begin to time the firing - do not start timing until then.
- Continue to heat, keeping the glow, for the recommended length of time.
- If the piece starts to glow a darker red, move the torch further away from the piece as it is getting too hot.
- If you can’t see the glow, the silver is too cold and you need to move the torch nearer.
- Leave to cool. If needed you can quench the silver in cool water, never quench if you have inclusions like CZ, gems, glass, or similar.
FIRING TIMES AND TEMPERATURE
The table below show the manufacturer’s recommended torch firing times. We suggest that you fire your piece a little longer than recommended, to ensure a strong end result. For the strongest silver you want to fire hot and long - for instance, rather than firing for 2 minutes, I would probably fire for 4 minutes. **You can NOT over-fire silver clay time wise, only temperature wise. Keep it at the right temperature (don't go over 900°C), and you can technically go for as long as your torch will cope!**
| CLAY WEIGHT | FIRING TIME |
| Up to 5 grams | 1-1.5 minutes |
| 6 - 15 grams | 1.5-2 minutes |
| 16 - 25 grams | 2-4 minutes |
| Over 25 grams | Fire in a kiln |
NOTES
- Tie up long hair, remove bangles and/or dangly clothes or accessories. You're working with an open flame, take care and the necessary precautions to keep yourself and your work safe.
- Keep pets and children (or chatty partners) out of the room, to allow you to focus on the firing.
- The torch can get hot enough to melt your silver. Dim your room to see the colour of your silver. If you see flashes of silver over the surface, pull the torch away as that shows the silver is melting.
- Torch firing is not suitable for projects that include glass, ceramic or porcelain or other materials that are sensitive to rapid changes in temperature.
- You can fire fine silver findings set in your clay safely with a torch.
- Kiln safe gemstones (5mm or under) can also be fired with the clay, but the torch can get very hot (over 1000C), so some stones can change colour.
GAS HOB/GAS STOVE FIRING - CLICK HERE FOR PRINTABLE INSTRUCTIONS
Is it really possible to fire silver clay on a gas hob? Yes, Art Clay Fine Silver (999) Clay is the only silver clay you can fire on your hob! As long as your stove is able to generate a capacity of 2.9kW (which most kitchen hobs and camping gas stoves do) and you use the recommended stainless steel - click here for net.
It can be tricky to see the colour of the silver sitting on top of a flame, so dim your room lights.
GAS HOB FIRING DIRECTIONS
1. Dry the silver. It’s very important the silver is fully dried.
2. Trace the outline. To be able to check if your piece has been successfully fired, you want to see if there has been a shrinkage. Trace the outline of the unfired piece on a sheet of paper. It's a good idea to snap a picture from straight above whilst the piece is sitting on the outline, so you can compare the before and after. After firing,
4. Check the glow. Place the stainless steel net over the burner. Make sure the net is balanced and secure. Turn on the burner and find the hottest area of the net by its red glow. Turn it off.
5. Place silver on net. Immediately place the silver on the hottest part of the net using a pair of tweezers.
6. Fire. Turn the burner back on. Once heated up, you may see a small flame for a few seconds as the binder in the clay burns off. Soon the piece will begin to glow. It is easer to see this if you dim the lights in the room. Try to aim for the same colour we recommend for torch firing (see image above). Once glowing, fire for 5 minutes. For safety, don't move or touch your piece or the net during firing.
7. Cool. After firing for 5 minutes, turn off the burner and let the silver cool on the net for about 5-10 minutes. If you try to remove the piece before it has cooled it may stick to the net. When the piece is cool it will easily detach from the net.
8. Quench. After cooling for 5 minutes, if you are in a rush you can quench cool the silver. Pick up the piece with tweezers and dip it into water to quench cool it. The bowl should be made of stainless steel or glass. ONLY do this if there are no inclusions in the silver.
9. Check the silver has shrunk. Compare the fired piece with the traced size you did in step 2 - Art Clay Silver contracts 8-10% in volume after firing so you should see a slight shrinkage. If it hasn’t contracted, the piece has not been successfully fired. Repeat steps 6 – 8.
IMPORTANT
- Size limitations: Under 25gm of clay, 5cm x 3cm. Max height 2cm.
- Don’t use any supporting material such as fibre blanket or vermiculite.
- Don’t fire hollow pieces with burnable cores, like wood clay, on the gas hob.
- You can’t fire Art Clay Gold with this method.
- Make sure the piece is completely dry before firing. It is best to dry it overnight in a warm place.
- If firing Art Clay containing fireable gemstones, it is safer to let the piece cool slowly between two pieces of fibre blanket.
- Please keep children and pets away whilst firing.
- Remember your piece will be glowing hot – don’t try to move it once you started firing.
- Don’t lean over the flame. Don’t wear dangly clothes or jewellery which may catch on the net.
