After a week of testing, I have found that COke bottle caps are melting great at 231c
This is 450c which is a bit on the high point of the plastic injection mold temp reccommended for this plastic, however if the plastic is melted inside the mold and the mold is closed, it does not get enough air to start to oxidize.
The photo shows some black spots that is just mill scale from the mild steel plate. I did not remove the mill scale from it before use.
Looks good! How big is the block, is this from your 1ft compression mould? And how solid is it? I can see what looks like a few gaps/bubbles on the edge but the rest of it looks pretty solid, though it’s hard to tell from the photo.
