Epoxy, Resin or What ?

I have some cracked fiberglass in my bilge where water seeped in and froze after many winters. Can I use a liquid epoxy or something else to seal the cracks before I lay some mat or cloth over it ? The hull is totally dry, water invasion was due to cracked gel-coat which is being re-applied.

 

You need to send pics of what you have. The gelcoat cracked because of what happened under it.

 

What did the water seep into?

 

It puddled down inside the hull around the centerboard well. When I removed the waterlogged foam in the well I saw a bunch of cracked resin at the bottom. Guess I should remove the outer section so I can see how bad it really is, but it doesn't look very good.

 

Grind out each crack, plus the surrounding areas and wet them out with neat epoxy. Apply cloth to the ground out areas to restore the laminate to it's original thickness. Then apply more neat epoxy to the repaired area to seal it up from more moisture invasion. Of course the laminate needs to be very dry for this to work.

 

Well, after removing the outer section inspection revealed that water has saturated the roving (black in several spots) so I'm grinding it all out and will rebuild with epoxy. I'm thinking of using fiberglass sheeting to rebuild the inner section, will epoxy bond with it ok ?

 

Best dry out area. You can use polyester or epoxy. Epoxy is much better. But if you use epoxy don't mix fiberglass resin in repair, fiberglass won't bond o epoxy.
Water or even moisture in area will weakened repair. You can dry with time, heaters or sometimes in a hurry use acetone. Or all three.

Epoxy is then times better than polyester.

 

You need more then epoxy, you need to replace the laminate too. Use cloth only with epoxy, no mat. The black spots may just be mold, so be sure you're removing bad, not just dirty laminate.