Anybody have experiencing machining lava? I need a plate that can be easily drilled, and can withstand high temperature (annealing iron in a kiln). Are there gotchas I need to know about drilling lava? Do I need special tools (there could be up to about 100 holes in the piece)? Does it crack easily?
Here's a web page on a lava I'm considering:The same company offers a partially fired alumina bisque that might work, but it shrinks 15 to 18% on firing. That seems like a lot to me, and I'd be worried it would distort.
If anyone has experience with another favorite material that takes high temperature (at this point, I can't say exactly how high -- dull red heat, maybe, for a few hours), I'd like to hear any recommendations. Must be electrically non-conductive. Must be non-magnetic (in the usual sense -- i.e. weakly diamagnetic). Cost is not a big deal (it's a one-of-a-kind prototype -- labor cost will be high, so saving a few bucks on material won't matter). Must be available in small quantity (like one, plus a few extras to break, if it cracks easily).
I'd like it to be as thin as possible, which would imply high strength, but I wouldn't want to use a ceramic if it's going to distort when fired. If it shrinks very uniformly and predictably, maybe I could use it, but I can't afford to go through several rounds of redesign and learning curve to understand how to work with the material. It's got to be cut it, fire it, and it works.