While I wait for machines to build, I have been melting in my oven to form plastics into molds. I have been using cookie sheets with either parchment paper or silicone baking sheets to prevent sticking. However, it seems that sometimes the HDPE sticks fiercely to either the silicone or the parchment paper, and other times it doesn’t stick at all. Does anyoen else have experience with ideal temperatures for HDPE to melt together but not stick to silicone?
It has also seemed that Polypropylene (PP) sticks like crazy at any temp I have tried. any suggestions there?
Hey there @minnesotadad!
From tests I have been making; it seems like greasepaper is what works best for HDPE bottlecaps; you have to be careful with the temperature + time being heated for the greasepaper to not burn (will be impossible to remove from plastic then..)
For other plastics; i mainly use aluminium or tempered steel made bowls in which i have put some butter everywhere the plastic will be in contact (very easy removal for PS)
I am also playing with hdpe and i just put a litle extra flour on the baking paper.
I mainly heat up a 175- 180 degrees to be able to hand mold the plastic (with gloves).
I also use glass bottle as rolling pin (just like pizza dough) to get it less think (but you can alway fold it) and better plastic consistancy.
Thanks for the input! Have you guys noticed a different level of “stick” with different HDPE applications? Injection molded stuff seems to flow much more than blow molded, and get stickier.
I wonder if PTFE (TEFLON) would not be a good non-stick material here.. Melts at 327 degrees C. After all, it’s already used to make cooking pans non-stick! Dropping some molten plastic onto a new non-stick pan surface would be a good experiment. I’ve not looked into it, but you can probably buy PTFE as a film, or a thicker sheet if you want to fabricate a mould out of it.
We have no problems with items sticking to our sandwich press and that has a Teflon non-stick surface so I assume a tray would act the same.
But have read that time and temp are huge factors of this. Too hot for to long = sticks.
hi, I was just looking at this on youtube. I put the link in so u can have look and hopefully it helps a bit
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