Working in metal clay is great for beginners who can now make amazing silver jewellery without expensive tools or training. However there's a catch - firing it correctly is essential.
That means getting the piece up to the right temperature and holding it for enough time so that the atoms all the way through the piece can be 'sintered' and all the organic clay binder part burns off. When pieces are not fired through properly they are brittle and may snap, or if they are fired too hot, you can be left with a puddle of molten shapeless Silver :(
Read on for three ways you can convert silver metal clay into shining metal.
The easiest and potentially most accessible way to fire silver metal clay is by putting it on stainless steel mesh and resting that over a gas hob on your stove. One of those old school bread toasters works well enough for this purpose, you can buy them at BCF or any camping outdoors store. This method is fine for tiny designs like silver buttons, or small thin pendants, as it will get the metal to rest at a nice salmony pink colour that is required for sintering. However I would only ever use this method for your smallest pieces and only things that were never going to require bending, such as small silver beads or charms. If you're making anything more intricate or bigger than those things you're going to want to move onto the next firing option.
The best method of firing when you're just setting out is to use a hand held butane torch. You can buy small creme brulee torches, you can buy larger butane torches from Bunnings. Both of these options have a place, but the smaller torches can be limited and the larger torches can melt metal pretty easily. The safest and most effective option for a beginner is a medium sized butane torch that you could buy from any decent online jewellery supplies store. You'll need to buy the gas separately, and work someplace that is fire safe and with decent ventilation because the fumes aren't good to breathe in. When I first started with metal clay, I used to work over my gas hob stove with the extractor fan running, and several fire safe vermiculite bricks as firing surfaces. Obviously you'll also want to wear covered in shoes, eye protection and clothes that aren't going to get in the way and catch fire.
Torch firing is exciting - the binder burns off with a bright yellow flame and its all pretty good fun. But, you do have to be careful not to burn your silver up. When you leave the flame on the same spot for too long, the surface of the piece will start to shimmer and dance... the next thing you know you'll be left with a ball of molten metal. Which is totally cool if that's what you're going for, and a massive bummer if you put a lot of work into the piece!
You can use a larger torch to create some cool effects such as reticulation or frosting, particularly if you like a rustic roughed up kind of look on your jewellery. Again, it's definitely the most accessible option for people just starting out, but over time you'll probably find it limits your design options. There's nothing worse than creating something gorgeous, firing it with your trusty torch, and then having it snap on you because it was a little too big or thick, and the torch heat wasn't consistent enough to burn the clay out of the metal all the way through. Mucho sadness! :(
When you inevitably start wanting to make bigger and more intricate pieces, you're going to need to own kiln, or to hire someone else's. Kilns can hold the temperature to a precise level, an extremely hot level (up to 1400 C!) without burning your silver up, providing you follow the manufacturer's instructions! :)
Kilns are less visually exciting because you don't get to witness the burn off and the clay going that bright salmon colour it glows when its sintering. Plus a full cycle takes a lot longer by the time the machine cools down enough for you to open it (#hotashell) But, you do get to go to bed while the technology does its thing, and that's pretty cool too. Typically, my pure silver pieces spend at least an hour soaking in 880 degree heat. If I'm making a ring out of metal clay (typically Stirling) I will soak them for three or more hours depending on how thick the metal is.
After the cycle is complete you can collect my pieces. They come out with a white coating which is the remains of the organic clay part. That gets scratched off with a wire brush, and if I'm after a really shiny look I'll drop them in my tumbler to polish them up. Then it's time to turn the pieces into jewellery! We'll take a look at that in the next post.
I'd love to hear what you think, feel free to introduce yourself and share your metal clay firing stories or questions?