Re: Help fiberglass repair
The method shown in the video will work, but is overly complicated and not the way it would normally be done.
To start with don't cut a hole, its a waste of time and creates more work.
Since you can get to the inside, grind the area as shown in the vid, but do it on the inside, not the out side, and remember don't cut or enlarge the hole. Use a grinder with 24 or 36 grit paper, the type of pad and paper shown in the vid will typically catch the edge and self destruct at the most inopportune time and possibly launch the grinder across the room. Grind it thin, but don't enlarge the hole or sand through the hull.
Now you have a small hole, or actually in your case a crack, not much of a difference though. Put a piece of tape over the outside, clear packing tape works well, but most any tape will do.
Glass the inside with enough layers to about match what was there to start with, but going thicker won't hurt anything. Don't worry about making the glass match the tapered area too much unless it will be visible. You do need to sand any surface that will have glass applied to it though.
When that's hard, pull the tape off and get the grinder out again, a sander like they showed will work for this, but a small grinder will work just as well. Grind away any of the remaining glass on the outside that is in bad shape, depending on the reason for the hole or crack, there may be a lot of damaged glass, or very little. Damaged glass looks white, or very light, good glass is normally an amber or brown color.
The damaged glass you need to grind away on the outside should be very thin because you will have removed most of it from the inside. Many times you are just doing a small cosmetic repair at this point, because 95% of the work was done on the inside.
Add a layer or two of glass to replace what you sanded off, then sand and fair as needed to make the surface look like you want it to.
Now you can use gel coat or paint to finish the job.
You can use epoxy or polyester resin to do it, either one will work fine.
