: I looked and I found the other board is (rec.boats.building). The discussion
: to which I refered is called "glassing an older boat". . . . I really feel
: that I know much more about the benefits of polyester resin as opposed to
: epoxy after having read the most recent post. This helps me as I have been
: using epoxy coatings on wood shifters and emergency brake levers. I feel
: now that I should use polyester due to epoxy's need for a UV protective
: layer. Thank you much. Garth

Before you change: Have you had any problems with what you are currently doing? Or are you just trying to anticipate problems so you can avoid them?

Consider the actual usage of these parts. Why did you coat them with epoxy in the first place? Why not paint or varnish?

As far as coatings go, it is not just a matter of epoxy or polyester. You have a lot of choices.

I use a polyurethane on my wood floors, and it holds up for years -- even with lots of traffic. Epoxy might last that long. I wouldn't think of using polyester resin, though. It would be too thick, it would not soak into the wood grain to protect it, and it might be more brittle. Also, I'd have to coat it with an air barrier or the surface would not cure.

A pigmented epoxy lasts far longer than a clear epoxy as the pigment blocks the UV, so if you are using an epoxy based paint the situation is different. For example, there are epoxy-based floor covering systems (I hesitate to call these "floor paints" as they do a bit more) which are pigmented (usually gray or brown) and also contain flakes of additional colored materials. You paint concrete basement floors, or garage floors with these materials and they last for decades, protecting the concrete from oil spills, water absorption, cracking and abrasion.

If your parts are exposed to the weather constantly then the epoxy will seal the wood. Polyester just doesn't do that, although it may protect the parts as well.

Varnish, Tung oil, Linseed oil, and several other oils, that have been thinned will soak into wood and protect it, too. Just put on a lot of coats.

If you are looking for a bright, highly reflective, polished finish, epoxy makes a great base coat. Consider using it as you would use a primer. Sand it smooth, then cover with varnish or polyurethane to fill in the tiny sanding scratches and give you a glas-like finish. This multiple material method may be a better apprach than trying to finish these parts with a single coat of polyester.

One of the other posters on this list (I think it was Spidey) has mentioned a method used by surfboard builders by him. They build with epoxy resin and then cover it with a layer of polyester resin. This sounds like an interesting approach as the epoxy seals the inner materials, while the polyester forms a durable outer layer, and blocks UV.

As always, test, test, test. and if you find a better method, write back and tell us. Lots of people interested in these things!

hope this helps.

Paul G. Jacobson