polyester resin and West epoxy compatible

[breakin wind]

Can I put West 105 over polyesther resin patch or vice versa?

[sawcat]

Breakin wind, I believe the West system was developed mostly for repairing old boats which means it would have to be compatible with polyester resins I ran across another epoxy resin when I was rebuilding my boat. I love the stuff. Go to Rot Doctor.com . Depending on what your using it for . The resin is thick compaired to polester resin so wetting out large areas of thick cloth is tough. It's an excellent filler mixed with aerosil. It's great to wrap stringers with cloth.It's two part mix no hardener. It' very expensive but about the same as West system.West system you have to buy hardener too. The polyester resins get hard and brittle thats what great about this stuff it gets hard don't get me wrong but not brittle . A very thin strip of this stuff will bend with out breaking it's cool. The benefit of this is that it's less likely to crack. Check it out. .they have a good website and really fast shipping. Be sure to check out the CPES it's a sealer that I used on seat frames stringers,deck plywood anything wood great stuff. Be aware that this resin is very slow drying, but they have two formulas cold & hot weather I highly recomend checking out there website
SAWCAT '92 Pulse 185

[Mark]

Can I put West 105 over polyesther resin patch or vice versa?
Epoxy will adhere to polyester but not the other way around. If you are doing big repairs with mat I would use polyester. It is a lot cheaper. Epoxy is great if you are injecting it into a void or filling holes. If the hole is more than 1/4" I would use glass fibers to give it integrity.
CPES is merely epoxy thinned with xylene. That is why it cures so slowly. They use it to penetrate into rotten transom wood. It will not work if the wood is wet and it is not as strong as unthinned epoxy. Sometimes it remains rubbery forever. (A better choice is a high viscosity epoxy if that is what you are doing with it)

[sawcat]

Mark,You are right polyester resin DOES NOT adhere well to epoxy.I left out the vise-versa.Thanks for picking me up on that . SAWCAT