Its always good to stay with what the boat was made out in terms of chemistry and construction.
If you use Polyester, work outside, wear gloves. Long sleeves, long pants, and a mask are all good precautions. And dont smoke while doing the repair, its flammable.
Here a blurb from US Composites on Polyester Resin.
Polyester Material Info:
Polyester resins are the most commonly used matrix in the marine and composite industry. These resins are styrene-based, flammable and catalyzed when combined with Methyl Ethyl Ketone Peroxide(MEKP). When working with these resins in large projects it is advised to use gloves and a chemical respirator to protect yourself from the fumes. These resins can be used with any type of fiberglass, carbon fiber or kevlar, as well as used over urethane foam and other sandwich core materials. These resins tend to be fairly rigid when cured and also more brittle than epoxy resins.
http://www.shopmaninc.com/polyesters.htmlhttp://www.shopmaninc.com/pdf/MEKPDirections.pdfEpoxy
Room cure type epoxy will soften in the sun, but the surface temp needs to be over 120 deg F for West and 140 for MAS, so the bottom of the boat isnt going to get that hot, unless you leave the hulls sitting on the black pavement and then stress them in some way you could be in trouble, not likely.
If you use Epoxy, I recommend MAS, the slow hardener is no blush, and they make a no blush fast. Epoxy isnt as toxic, but you need to be more precise in mixing and measuring it. Wear gloves, dont get the hardener on your skin. MAS is low VOC so you dont need a mask. Work with epoxy in a dry, 70deg area, like a nice day in the shade, or a garage. Uncured epoxy doesnt like moisture, so evening dew, or fog could mess it up.
I use peel ply on all my repairs, it goes on top off the last layer that you are leaving to cure, and it peels off after the area is cured, it helps keep everything held down nicely, and it lets you squeegee the fiberglass down and get the repair nice and smooth. Fiberglass gets realy slippery when its wet out with resin, and its hard to keep it straight, plus the fibers come off easily. Peel ply makes it less of a mess and make it easier to work the cloth and get it all smoothed out nicely.
If you use Peelply, the amine blush forms on the outside of the repair, so when you peel the ply off, the blush comes off. No washing the blush, which is a pain in the ***.
Bill
