Old Debate Revisited - Poly -v- Expoxy - which??
 

Looking to rekindle a debate not covered as much as I thought it would be. Polyester -v- Epoxys, what do you use and why, and what do you recommend?

Thanks,

John

Re: Old Debate Revisited - Poly -v- Expoxy - which??
 

John

I've just finished using gallons of both in my rebuild.
I'm hardly an expert at this but my perceptions are as follows:
For all the below deck replacement work I used Raka Epoxy and I was very pleased with the results. Only down side was the price, which varies with the amount you buy but you can figure on about 40-45 / gallon. When it came to the topside work, I switched to Poly as I wanted to redo the gunnels, insides and floor with gelcoat. I bought the material from Joe Merton in Springfield. Joe also sold me on rolling the gelcoat on the insides and floor and this came out pretty well. Joe's Poly is hi grade and I was very pleased with it as well. It costs less that the epoxy and sets faster. While I don't know how you will be using the material, be rest assured either will work well if properly mixed with the correct fillers, ie. cabosil, glass spheres, chopped glass and talc. I used all of these in different applications.
If you tell us more about how you will be using it perhaps I can add a few more cents. Hope this helps. Dink

Re: Old Debate Revisited - Poly -v- Expoxy - which??
 

I'm looking to do several things, recore some hatches, some console work, repairing small cracks, edges, bulkhead, etc. Eventually I hope to do some work re-arranging the splash well.

Re: Old Debate Revisited - Poly -v- Expoxy - which??
 

I've used epoxy for everything on this last project... mostly because I like the properties.. slow cure (I've been told that you can still get chemical bond up to 5 days) strength, ability to bond with just about everything and ease of use to name a few. It costs more and that is a problem if you are making fiberglass parts. I would use Vinylester if I were to build another engine bracket just because it is cheaper and wets out a little easier and thats the only reason. I'd keep it simple.... for repairs use good quality epoxy.. for making large parts go with polyester or vinylester.

Strick

Re: Old Debate Revisited - Poly -v- Expoxy - which??
 

I used about 12 gallons of epoxy to do my boat and if I had to do it again I would use EPOXY all over again. I don’t consider myself a boat builder I became a boat re builder to get what I wanted which is a 1977 23’ SeaCraft. The stuff works great especially when you don’t know what the heck you are doing especially when it comes to drying time. The only concern one would have is if you are planning to re gel coat over epoxy. Some epoxies and gel coats don’t marry well. I used West Epoxy which is not cheep but will work with gel coat for those that wish to use gel coat. I painting every thing so it didn’t make any difference. Most guys would say for new construction you can use polyester or vinyl ester but for re doing stuff use epoxy, for me since I am a better fisherman that a boat builder, EPOXY is the only way to go for everything.
FellowShip [img]/images/graemlins/wink.gif[/img]

Re: Old Debate Revisited - Poly -v- Expoxy - which
 

JohnR - where your going to be doing this work?

Polyester and Vinylester has an offensive odor that will almost gaurantee "pissed off neighbors". So when you're evaluating the extra costs of using epoxy . . . make sure you factor this into your calculations.

Also like Strick, fellowship and the dink already said polyester and vinylester wet out the fabric much quicker than epoxy, so it's a better choice for making new parts.
Poly/Vinylester will also bond well to gelcoat if your using a mold unlike epoxy.

Re: Old Debate Revisited - Poly -v- Expoxy - which
 

So tell me if I'm on the right track here for my upcoming transom rebuild....

1. Epoxy to laminate the new core to the existing outer skin.
2. Epoxy to lay new glass over the new core.
3. Epoxy to make any repairs to the stringers.
4. Epoxy to bond the aft deck/cap back into the boat.
5. Polyester to build a new transom cap where the motor well used to be as I'm going full transom/bracket.

Sound good???

Thanks.