My experience with the pl was somewhat similar. It never worked for me . I even let the PL it sit for 10 days second try. It still reacted with the 435 resin in some areas. I even ground the fillet PB material I used to finish my filllets back off the PL after sitting a few days just to see. I found the PL was like a toffee consistency and I could scrape it off under the PB. I also found that beads that I let cure on the hull in sanded and prepped areas for a test , I could pull up. It does not bond very well to cured fiberglass.
One could brace across the top with 1x2 brad nailed in... Everything is held in place while you fill in under everything with PB. Like I said though I'm probably still using PL to bed all the wood stringers then doing the fillets with PB. But the keel stringer is getting done completely with PB. I need it dry as soon as possible to get it glassed in because it has to be finished before any other stringer can be installed.
Sorry to hear about your luck with PL Like I said earlier after using PL in a few places I found it had no bond strength to any cured fiberglass. Gelcoat would be in that category. I never used it at all after my findings. It is great for bonding wood and a filler but to bond to fiberglass it is a no go in my books. I don't know what to say to fix your problem but from what I can vision it is not a good situation to have the outer skin loose. Hope the PL gurus have a suggestion for you.
