Firing

Coming Soon

• Firing gemstones in place
 Glass can be fired at very low temperatures. I fire dichroic glass in PMC3 to 1200ºF. GemResources.com has fire in place natural stones and has a disclaimer on the ones that CAN be fired in metal clay. CoolTools.us has a chart somewhere on their site. Whether something can or cannot be fired in metal clay has nothing to do with the MOHS scale of hardness. Each stone has it's own properties regarding heat tolerance. Some stones that are usually considered safe to fire in place, may not survive do to the specific stone's internal structure (fractures, etc.) Crystals, like Swarovski, cannot be fired in metal clay at any temperature.

• Your new kiln should come with posts and a fiber shelf. If it doesn't make sure you get (4) 1/2" high ceramic posts. I would replace the fragile fiber shelf with a soft Solderite soldering board. You also want to have support materials on hand for whenever you need them. Fiber blanket and/or vermiculite. I use a casting crucible to hold the vermiculite. You might want a long handled spatula to remove the shelf while hot. You want to create somewhere to set hot work, some kind of metal or ceramic heat proof surface. I use a cookie sheet, but I'd suggest something smaller. To fire base metal clays, you need carbon and a stainless steel container. I love the one that Ed Martha Biggar (Martha) sells. It's expensive but will last forever. Other containers spall flakes of steel and make the kiln dirty, and the spall reduces the life of the container. (people tend to use a restaurant sauce container or pet food bowls). You might want a slotted metal spoon to fish your work out of the carbon.

• About "Sintering" - Think of ice cubes. Right out of the freezer, they are fully frozen and separate - Imagine this to be the unfired state of metal clay. Leave them out for 10 minutes and the 'skin' of the cubes start to melt. Put them back in the freezer and the 'skin' of each cube bonds to it's neighbor, but they are mostly still separate and very easy to break apart - imagine this as underfired metal clay. Leave the ice cube tray out for two hours and it turns to water. Then put it back in the freezer and you get one solid tray of ice - imagine this as fully fired metal clay.

The truth is that metal clay fired at the hottest temp for the shortest time is much stronger than my example of partially melted and re frozen ice - but you get the general idea.