I have a project that is not actually guitar-related, but I thought you guys might still have some suggestions, being the rad bunch that you are.
Say you have a negative space, of a particularly odd shape, and you need to fill it. Not just fill it, but sort of overfill it, so that you can carve and sand back the excess to your desired shape. Anything pourable is out of the question, because you can't build walls around it. Wood or blocks of foam won't work either, the surface is really uneven. The ideal material would probably be modeling clay, but that's expensive, and besides requiring a lot of skill to lay up, you need a warm room and you don't have one. So what do you use?
My thought was plaster. Cheap, easy to work with, just glob a bunch of the crap on there, wait for it to harden and then carve it back. But I've never worked with plaster before, is it more complicated than that?
I'll tell you guys what I'm working on, it's a motorcycle that I'm making custom body work for. Ultimately the body work will be made of fiberglass or carbon fiber, but I have to first create the positive space shapes I want to duplicate, and they have to fit the complexities of the bike frame and some other components. Custom motorcycle builders do this kind of thing all the time, but they use blocks of foam, which won't work for me. So I'm at a loss, and am turning to y'all for help.
And for the record I'm trying to get back to making guitars too, but in the meantime, I wanna zoom around on my go machine.