2EFNFAST
11-20-2009, 11:41 PM
I figure a few of you guys on here have to have some knowledge on fiberglass/gelcoat work.
I do'nt have a problem with fiberglass (making plugs, repairing holes, etc....), but rather the gelcoat portion. Namely 3 problems.
(for the below, assume you just have a flat board of fiberglass with a gelcoat finish; you take the dremel and shave off a patch of gelcoat to repair)
1 - When the gelcoat cures I keep getting teeeny tinnnny craters in the gelcoat. I've tried really wiping the area down thoroughly with acetone several times before I apply the gelcoat, and I've tried using 1% MEKP, mixing anywhere from 6-10(10 is the recommended) drops per ounce of gelcoat. Doesn't matter what I do, crates keep coming up.
2 - If you're applying a layer of mylar over the gelcoat while it cures, are there any good tricks to prevent the gelcoat from spreading too much? What I mean by this is I lay the mylar down, tape it down at one end, then use my squeege and squeege along it to remove allt he trapped air, then tape down the other 3 sides. Of course doing this smears gelcoat everything underneath
3 - When doing the initial sanding to level the gelcoat with the surrounding surface, I usually do 150 by hand (Sanding block) to start, working as carefully as I can, then when I don't think I can be careful anymore I switch to a da palm sander (5'' circular one) and do 220. Is this okay to do? Sometimes I see the pattern beneath the surrounding non-repaired gelcoat meaning I sanded too much, but I can't figure out if it's because the surrounding area isn't very thick, or if maybe I just have to do it all by hand.
I do'nt have a problem with fiberglass (making plugs, repairing holes, etc....), but rather the gelcoat portion. Namely 3 problems.
(for the below, assume you just have a flat board of fiberglass with a gelcoat finish; you take the dremel and shave off a patch of gelcoat to repair)
1 - When the gelcoat cures I keep getting teeeny tinnnny craters in the gelcoat. I've tried really wiping the area down thoroughly with acetone several times before I apply the gelcoat, and I've tried using 1% MEKP, mixing anywhere from 6-10(10 is the recommended) drops per ounce of gelcoat. Doesn't matter what I do, crates keep coming up.
2 - If you're applying a layer of mylar over the gelcoat while it cures, are there any good tricks to prevent the gelcoat from spreading too much? What I mean by this is I lay the mylar down, tape it down at one end, then use my squeege and squeege along it to remove allt he trapped air, then tape down the other 3 sides. Of course doing this smears gelcoat everything underneath
3 - When doing the initial sanding to level the gelcoat with the surrounding surface, I usually do 150 by hand (Sanding block) to start, working as carefully as I can, then when I don't think I can be careful anymore I switch to a da palm sander (5'' circular one) and do 220. Is this okay to do? Sometimes I see the pattern beneath the surrounding non-repaired gelcoat meaning I sanded too much, but I can't figure out if it's because the surrounding area isn't very thick, or if maybe I just have to do it all by hand.