I use this stuff infrequently. It’s Newport heavy glass with the pink plastic backing. It always gives me fits. I know it’s very hard to peel in hot, humid weather but I’m doing this in 75 degree, air-conditioned room. I use a utility knife to flick at a corner until it starts to lift. It takes me 10 minutes to get enough of the backing to lift so I can peel it off. Half the time, I can’t do it at all and just give up on the sheet.
Any tips, tricks I am missing?
cool the prepreg the best you can. I’ve hated ALL fiberglass prepreg except Cytec 7668 with 7781 glass. I’ve dealt with some that had a layer of epoxy only on ONE side…you touch it wrong, and it gets stuck everywhere, and your gloves and the entire layer is trash. The best is to cool it down good. Maybe stick it in the freezer quick, pull it out, and use it…
you could try adding a little tab on to your pattern where you want to peel it, cut in to the fabric but not the backing, and peel the backing off by bending the tab back. You should be able to request for another type of backing that will peel better, worth contacting the manufacturer.
23deg is quite warm for prepreg backing removal. We try to keep our clean room around 18 to 20deg as it makes a big difference. We have had some material we had to freeze before hand and then pull of the backing paper and then wait for it to defrost. You could try ‘freeze spray’ to spot cool the paper.
Also letting it ‘degas’ helps. By this I mean unroll what you need and let it sit for a day or two to allow the VOC’s to evaporate, effectively letting it cure a bit.
Thanks for all the advice. I found a trick entirely by accident. When we receive the roll, we often cut a batch of it to size and refreeze it. One of my technicians was a bit sloppy and some of the sheets were folded over before freezing. I discovered that the backing was lifted off in these folded areas, giving me a bit of backing to grab onto.
So, I folded a corner on each sheet, stuck it back in the freezer and when I removed it an hour later, there was a nice little pre-lifted part of the sheet.
Also, as Moke suggested, 23 is a bit warm. I cranked the A/C to 19, let the material sit for 2 days and it was much easier to work with.