From: "John F. Howard"
Sender: Star45@yahoogroups.com
Date: Mon, 1 Oct 2007 10:08:21 -0500
Subject: RE: [Star45] Re: Epoxy Finish
Al, Epoxies stink a lot less than polyester resins (saves problems with the other half, neighbors etc) Epoxies can be clear to allow the wood to show thru (they will need a coat of UV Varnish to protect them or the epoxy will turn amber), polyester resin is not clear, usually has a green or blue non-transparent tint. Epoxies have a greater adhesion to wood Epoxies are a little softer than polyester, but for our use the difference can’t be seen or felt. Epoxies have a longer pot life and working time Epoxies are a little more flexible in the mix ratio (one or 2 drops one way or the other won’t make a difference with epoxy where a drop too much or too little of catalyst with polyester can make it set up too quick or not at all). Epoxies cost more than polyester, but the above advantages out way the cost. Epoxies do not expand like the polyurethane glues (Gorilla Glue) and additives can be used to modify the strength (colloidal silica for strength, micro balloons to lighten and make sanding of fillets easier) Epoxies take less fill coats over fiberglass than polyurethane (water or solvent based) Those are just a few reasons off the top of my head and I am sure there are more pro and con.
