Resin Question

[Restless]

Are you using polyester or epoxy resin to rebuild your transoms?

I would assume that polyester resin would work perfectly fine on the stringers since that is the original material, but would be concerned about polyester delaminating from plywood cored transoms after a few years.

[wingtime]

It comes down to how are you going to refinish the transom when you are done.  You can not put gel coat on epoxy since it won't stick to it so you have to paint it.  Polyester resin does not have anywhere near the secondary bonding strength of epoxy (sticking to cured resin) but you can gel coat it.    Epoxy is much more expensive, but it's stronger and resists water better than poly.  If you use polyester make sure you get a good high quality resin that is FRESH.

[seabob4]

How about vinylester?

[dbiscayne]

Vinylester is good stuff, also can be gel coated, and falls between polyester and epoxy in terms of adhesion.

Everything Wingtime said is true, except I haven't found epoxy to be much more expensive than polyester or vinylester.  Theres several local shops in south florida selling 1:1 and 1:2 epoxy for around $45/gallon, been using it for years with no issues.  Other advantages besides much better secondary bonds is the lack of smell from epoxy and a longer working time = less waste.

I would assume that polyester resin would work perfectly fine on the stringers since that is the original material

You'd be better off with vinylester or epoxy- when dealing with cured polyester resin you're best bet is to use epoxy, especially if you're not going to gel coat it.  If the layup was new and everything built wet on wet the poly is fine, cured poly is a different case.

[Curious]

I poured my transom using Nida Core pourable transom compound.  Since the Nida Core material is polyester based I used polyester resin to do the finish glass work.

[Restless]

You'd be better off with vinylester or epoxy- when dealing with cured polyester resin you're best bet is to use epoxy, especially if you're not going to gel coat it.  If the layup was new and everything built wet on wet the poly is fine, cured poly is a different case.

Good point. The secondary bonding strength of poly is not very good.

[kraw2]

You wouldn't believe how many new boats are still using Polyester resin..!

[wingtime]

You wouldn't believe how many new boats are still using Polyester resin..!

New is not a problem since you are dealing with all primary bonds if the hull is layed up correctly.  Quality boats should have at least a barrier coat of a higher quality blister resistant resin.

[dirtwheelsfl]

I would AT LEAST bond the 2 pieces of wood together with epoxy. If you have your heart set on re-gelling, do the rest of the laminating with vinylester. Its possible with epoxy, but difficult to get good results (meaning adhesion).