Question about plastics

[PatrickR]

McMaster.... I love that place. i always have stuff in my cart. I looked through the plastics and there seems to be several options for you.

[Sylvanite]

Originally Posted by bmachin

Acetal (Delrin) maybe?

Delrin works quite well. I bought a box of Delrin pieces several years ago and have used it for molds (PR, Alumilite, and silicone), bushings, gluing jigs, and custom mandrels for CA build-ups. Nothing sticks to it.

That said, any mold (of any material) that gets scuffed over time will eventually become difficult to demold from. A good mold release agent will help tremendously. So well, in fact, that the actual mold material becomes less important. I use UMR mold release. With it, you can even cast silicone in a silicone mold (without it, the two will fuse permanently).

I hope that helps,
Eric

[chartle]

Certain HDPE plastics can be melted into blocks. Its any thing made from HDPE thats been injection molded not blown like milk bottles. HDPE for bottles is just a slightly different mix and doesn't melt nicely. The injection molded stuff melts down like thick wax.

I've been making blocks upto breadpan loaf size. Luckily I have an endless source of HDPE from work.