This may be baked, but no one seems to sell it and I do not know why. I am not a chemist, but it sounds quite bakeable. Suppose two large cans of substances A and B were supplied, which, when poured into a mold fashioned out of a suitable material, will yield usable plastic. As an electronics hobbyist, I cannot seem to get decent cases to fit my projects anywhere. All of the standard-manufacture enclosures for sale (at places like Rat Shack, etc.) are always either too small or too big, and invariably must be drilled/sawed/etc. to allow the placement of screens/switches/other interface components. Ergonomic hand-held devices are simply impossible to produce using ready-built cases. (yes, this might qualify as a rant.)-- dsm, May 22 2001 Friendly Plastic https://www.amaco.c...dly-plastic-pellets"... the sticks soften in warm water for shaping with your hands or with other tools .... Once the desired shape has been achieved, place in cold water to harden." The result is hard plastic. [egnor, May 22 2001] Epoxy Resin http://pslc.ws/macrog/kidsmac/epoxy.htm [hippo, May 22 2001] Crayola Model Magic http://www.crayola.....cfm?Product_ID=165It's like Play-Doh, except that it hardens into stiff but bouncy stuff. I don't think I'd built an electronics case out of it, but I've made cat toys with it. It has the advantage of being non-toxic. [egnor, May 22 2001] Polymer Clay http://www.jaedworks.com/clayspot/"Polyclay" is fine particles of PVC suspended in plasticizer. You shape it like clay and bake it in your oven. The result is hard PVC plastic; it's generally used to make jewelry and knickknacks. [egnor, May 22 2001] Epoxy clay http://members.trip...los/epoxy/intro.htm"This is a two-component based clay that hardens in a few hours after you knead the two components together." [egnor, May 22 2001] The cheapest 3D printer on the market http://www.rolanddg...modelers/modela.aspDon't sculpt it; carve it. Sits on the desktop, driven by CAD model. [egnor, May 22 2001] Or, if you've got money to burn.... http://www.zcorp.com/noFlash/index.html [egnor, May 22 2001] Your local hardware store probably carries epoxy clay, which is almost exactly what you describe. (It's intended for repairing pipes and stuff, but as you can see from the link, it's perfectly suitable for modeling and fabrication as well.)
However, you should look into some of the other options as well; epoxy clay is sort of icky. Friendly plastic in particular might be useful. (Polyclay looks nice, but it requires baking; with the other materials, you could sculpt directly around your electronics and let the case set in place.)
I've personally used epoxy clay, friendly plastic (I used pellets, not sticks), and model magic; I haven't tried polyclay.
Having received this advice, you are now required by law to post photos of any interesting home-made hand-held devices you come up with.-- egnor, May 22 2001 To the curious, I am constructing for myself a portable HTML/GIF view panel, similar in purpose to the much-hyped "e-books". The currently available machines disgust me with their tiny screens and massive redundant features (i.e. modems and huge 24-hour batteries.)-- dsm, May 22 2001 I thought this was going to be a trainee credit card for first-time users, so they could practise before racking up a really *huge* balance on a real one.-- angel, May 23 2001 My mothers `rock buns`recipie had certain engineering applications- could be used as doorwedge/ motorcycle stand, and was virtually indestructable. Anyone else had such an ingenious Mum? Sealing wax is often overlooked. I made a 3d sculpt device for a few pounds using this. Also `Woods metal`- Stuff (poss) used by Uri Gellar in his spoon bending trick. Shall dig out the formula and post it.-- john b, Jan 02 2002 Some decades ago I used a substance called "Wonder Cast." It was a resin that was mixed with water- yes, water, tap water- strirred with an electric drill until it began to foam, then poured into molds. It hardened into an opaque plastic substance. I haven't seen it since about 1968.-- whlanteigne, Oct 05 2002 There is this very cool material I have used a few times - it is cheap and easy to cut to size, and smells kind of good when you cut it. Also you can fasten pieces together with glue or several different metal pieces marketed for the task. It is called "wood".-- bungston, Oct 23 2002 random, halfbakery