fiberglass crack repair

Bumpy, IF when you push on it you can see any movement in the sides of the crack you may want to get some epoxy, they sell a small syringe type of package that mixes in a tube and comes to a fine point. You could try to inject a drop or two of epoxy that way to stop movement at the top where the hole is drilled.

is epoxy a better seal than 4200?
there is no movement, can barely feel a crack with my fingernail rubbing across it.
bumpy

Cant say which is better, my only thought was the syringe to get the product inside the wall if it had separated. Since there is no play across the crack I wouldn't think it would matter.

Find a marine products store and get a gel coat repair kit. It comes with gel coat and assorted color additives so you can match the color of your unit.

Moved to Tech Issues forum from DIY.

It sounds like the crack is only in the gel coat and not through the FG laminate it self. If so I would leave it alone or put a decal over it if it bothers you. I agree with you, I would not do an extensive repair. Usually stress cracks in the gel coat show up in corners or radius of FG structures, yours is in the middle of the slide out. Is there any attachments on the inside that would induce a load in that area?

Marine Tex is good for this type of repair. It can be tinted. Excellent hardness and adheasion

this crack is in the middle of the "side" . I have no slide. I ordered the "access port cover" yesterday from Overton's and am now leaning towards drilling the two tiny holes at each end of crack ( I read here that that is recommended so the crack won't spread) and stick on a length of eternabond tape over the crack to keep out moisture. is the eternabond as "permanent" as the 3M sealant would be? it would be more flat and easier to cover than the sealant. again it is made with Azdel so I am not concerned with moisture/delamination etc.
it has been sitting for 2 years so don't know what could have initiated this crack other than perhaps something thrown up by a commercial lawn mower, etc.

thanks
bumpy

I would use the 3M 5200,4200, Marine Tex, gel coat or Geocel caulk, it will lay flatter than the Eternabond tape. When you drill your holes at either end of the crack I would put a small pick in there to see if the outer layer of FG is cracked through. I can't see why a FG crack would appear in a flat side other than when laminating the FG wall there was a butt splice in the outer layer and not an overlap. Gel coat cracks usually occur when the gel coat is put on too thick. Good luck with your repair.

thanks, I have a tube of 4200 so think I will just use that. I gather that the tape is thick then from your post?
found a short length of this: Eternabond Microsealant Tape on amazon?
may try it??
bumpy