Re: Small Gel Coat Crack
It sounds like you may be looking at a void in the gelcoat; Either that or there could be a screw poking through from the interior. If it is indeed a void, it's a fairly simple repair. The way I would check this would be to take a screwdriver and by hand press the tip into the crack. If it's a void, the gel layer will push in and chip without too much pressure, if not, then it's probably something coming through form the inside.
ASSUMING (famous last words) it's a void, you'll want to chip out all the gelcoat that is not bonded really well, sand the entire void with 80 grit and taper the edges around the area. Give a good wipe down with acetone to clean and use some type of polyester based filler (either thickened gelcoat, or a produect that I use quite a bit is called Adtech (which is essentially a gelcoat paste).
Fill in the void and sand flush (actually just a little shy of what the finished surface should be). There's a good chance you can get some color matched gelcoat from Spectrumcolor.com (they sell a little 2oz. touch up kit); if not you can try mixing the color yourself or just use the white gelcoat out of the can if you're not concerned about matching color. Add the hardener (roughly 15 drops Mek-P) per ounce of gelcoat and brush the gelcoat over the sanded area (I would do it in a few coats rather than try and lay it up thick enough in one round; it will tend to run). Each coat usually flashes off in 5-10 minutes (faster if you put a heat lamp to it. Warm, but not hot)). After it flashes (feels sticky, but no longer runny and hasn't cured) apply the next coat. If you do this 2 or three times you'll have enough laid up. After the last coat flashes, spray over the patch with PVA (poly vinyl acetate) with a throw away sprayer (Prevailer) that you can get at any auto store.
The next day wipe the PVA off with some warm water and take a sanding block with some 600 grit and wet sand everything down until it's ALMOST flush with the surrounding surface. Then progressivly work through the finer grits until you get to 1200 or so and everything is nice and fare. A quick buff and you're good as new. If you have to buy all the materials, it will probably run you around $50.. Hope this helps! Good luck
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