So I think I figured out the new name for my boat: F$!k Gelcoat! lol...
After multiple experiments on a variety of surfaces, and never quite figuring out what makes spots not bond, I have 97% of the cockpit floor nicely gelcoated, and then every single place that I've recently repaired with either TotalFair or Silvertip + glass tape went unbonded/cured, even after waiting a week. Put down about two and a half quarts with rollers, which itself was a pain in the ass because it seems gelcoat kind of eats my gloves, but got it down.
Here's what it looks like now after an hour of using up an entire quart of acetone scrubbing away the uncured stuff:
https://drive.google.com/file/d/1S-vqqB ... sp=sharing(Video link may not be uploaded yet but give her a try)
- shizz.jpg (78.55 KiB) Viewed 281276 times
- shizz2.jpg (78.71 KiB) Viewed 281276 times
My theory is that, even though gelcoat has been proven to bond to epoxy, including the epoxy I used (S3 silvertip) the non-bonding only happened on surfaces that were somehow "corrupt," either by being blushed (which may be the case at the top of the cuddy where there was green Totalfair) or, in the recently fiberglassed fillets, because I didn't wait long enough after the epoxy had cured to apply the gelcoat. I'm not sure. I think it was a good 16 hours between epoxying those fillets and tabbing the transom before I gelcoated, but it had also been somewhat humid weather so maybe there was still moisture in the epoxy unevaporated that messed with the gelcoat.
Or is there some phenomenon where epoxy isn't "really" cured after it's initial curing time? I use S3 Silvertip with the fast hardener which is supposed to be cured in just a few hours.
I definitely wish I'd just bought a bunch of mat and epoxy and re-glassed the whole floor, which would have made for a much stronger and easier surface to paint than the splotchy deal I have going on now. I understood (I think) too late, that Greenlake was recommending to do the gelcoat because it would essentially save me the money + work of painting it (since I could just dye it grey.) But when I made my order I'd planned to paint the floor all along, and even already had the paint when I started this woeful
gelcoat experiment.
Oh well, at this point I'm sorta commited since I'm not about to sand all the good coat off. My remaining ideas are:
1. (crazily) Try to use my 1/2 quart left to cover up the splotches. This would only be after making sure one of those spots is totally dry and de-blushed and testing it to see if gel holds this time.
2. Do some sort of fairing job with either thickened epoxy, or 3m high strength or QuickFair. Would be tricky because the gelcoat is just a few mils and it would be hard to fair that without wasting a lot of material, plus it's in tricky spots where there are 45 degree angle curves. I'm liable to just make my already amateur fillets look worse.
3. Say screw it and wherever it isn't easy to fair just paint over it and have it look lumpy. (Actually I'm a bit worried about paint adhesion because it was extremely hard to get into the nooks and crannies to remove the uncured gelcoat, and I'm pretty sure I won't have gotten all of it off.)
4. Lay on an extra layer or two of primer in the uncured spots to build them up to sand even with the rest of the gelcoat.
5. Some combination of all of the above.
My main concern is just moving the boat forward, as the cockpit floor is really the last thing holding me from painting and my painting weather is fast disappearing.