hi there
i am making carbon parts and have recently changed method to prepreg. i had some success but now not so much. my parst are hooking to the mould, and i am having real problems releasing them. i have made the moulds from high temp epoxy resin, and the tooling gel coat was high temp epoxy also. i have been using TR high temp wax as release agent. but this seems not to be working.
could i have some advise as to what is recomended for prepregs. and what mould surface is also best. also do i need to use a mould sealer before applying release agent.
thanks very much
marty
yes, you should seal your molds, this will reduce purosity. You will have best results using a semi-permanent release and sealer such as frekote.
Yes the molds need to be sealed first. And follow the manufactures instructions to the T to do so. Also make sure your molds can withstand the temp that your cooking your prepregs to, that can hinder your results if not ruin a mold real quick.
Frekote ftw
I had some issues releasing epoxy products from epoxy mould a few weeks ago.
As I didn’t need the full Tg from the resin, I didn’t postcure to the highest Tg. Epoxy sticks quite well, even with a semiperm; and even when it had hardened quite well. Seems you need to fully cure epoxy moulds first.
Phenolic wedges and Teflon wedges along with rubber 5 lb mallets are your friend. Make sure to wear thick leather welding gloves so you don’t slice your hand open. Parts don’t fall out generally speaking but when you cook. Your mold should withstand a good beating and smaller than a dime chuck sticking to part is in the norm.
It’s a pita ass sometimes and often people get discouraged when they start braking stuff. Aluminum and silicone tooling lasts much longer but is expensive and out of the average persons budget.
Ive had to spend hours fillin pits and repairing carbon tooling because the mold would start giving out.
My experience is that with a good mold release, parts pop out while looking at it.
One of my customers uses aluminium and Frekote, and his parts are always sitting loose in his moulds.
Also other customers do not seem to have problems, mostly using Frekote or Ferrokote (FS10)
people have problems with semi-permanents because they do not use them properly. Biggest mistake is not putting the lid on tight after using. Second mistake is putting it on too heavy or rubbing it in to the mold rather then applying it in straight lines. If your mold is constructed correctly and you apply the cleaner, sealer, and release properly you should never have a part stick.
thansk every body for the replys. im starting to put all the peices of the puzzel together. i did pre cook the moulds to the exact specs and pretty sur ei followed the release agents specs to. i also tried something else. i got a very very clean, sinny peice of glass, released it the six times as ment to, (i think i did 8), and then layed 8 peices of prepreg carbon on it and vacuum and cooked it. i still had trouble popping the carbon off the glass. how was that even possible??
Try contacting Carl at ACT (09 573 1970) and get some 19SAM mould release. We use it on all our parts with pre preg and I never have a stick up (when put on right). It’s not cheep ($NZ170ish for 1gal) but then nether is doing a job twice or reworking a part. It doesn’t need a sealer just 4 or 5 coats the first time and 1 every second time.
Glass is porous, as opposed to what people think. still it should have popped off, so I think your release is not performing.
buy some frekote, call it a day.
Just want to make sure. What IS your mold Marty? If your mold is complicated and has negative drafts in it, no release will help.