[gcn2339]

newbie here to vaccum forming... I was wondering if I could use machined hdpe as a mold medium for short run jobs using petg or would it melt?

[kayaker43]

Should work fine but sharp corners may eventually round off a tiny bit. It may also warp somewhat from getting heated on one side,.. depends on the shape?

[Lotus14]

Do you want to use the plastic mold forms because you have access to a bunch of big chunks of material?

Otherwise there are a number of materials that would be as easy to machine, aren't very expensive, and might not require the experimentation to make sure they work.

[gcn2339]

yes I have some scrap material laying around collecting dust… I really don’t do that much vacuum forming maybe only once a month.

I’m make mostly flat .25 inch dies