Re: How to patch using resin and fiberglass?
If possible do most of the repair from the inside, it may not be easy to get at, but it will give you a better idea of how much damage there is. You need to grind (4" grinder with 36 grit disc) out any fractured glass, it normally looks white, or lighter than the good stuff around it. Taper the glass out away from the repair a few inches so there is enough surface for the patch to bond with. You have a choice of epoxy or polyester resin, epoxy is stronger and will cost more, polyester is what the boat is made from, is easy to find and will cost less, it won't make a real difference in which one you pick. With polyester you need to start with mat as the first layer or it won't bond well, you should also use mat between each layer of cloth or roving. Build up the surface to match what the shape of the keel should be, use the grinder to help get the right shape. You may need to use a fairing compound to smooth it out and sand more with finer paper until you're happy with the shape. Gel coat or paint can be used to finish off the repair, with gel coat more sanding will be needed. If you plan to beach the boat frequently, then get a keel guard type product, it's a durable soft plastic strip that sticks to the area you just fixed, stopping the wear and tear on the keel.
