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Epoxy substitutes

Posted: Tue Sep 25, 2007 12:50 pm
by jem
Many builders don't care fore the cost of epoxy and I can't say that I blame them. Stuff is not cheap.

Many search for cheap alternatives. Polyester resin is often selected as one of them.

Epoxyworks (West Systems' newsletter) did a study about effectiveness of different coatings at keeping moisture out of a dried piece of plywood. The study had some interesting results.

I'm not sure how long the article will be there so I'll summarize. In order below, with 1 being the best and 7 being the worst, these coatings rank as follows:

1) West System 105/205
2) Vinyl Ester
3) Low Performance epoxy systems.
4) 2-part polyurethane paint
5) Polyester resin
6) High-solvent epoxy penetrating systems
7) Formaldehyde

Now this is a West System company study so I'm sure they are not telling what they consider a "low performance epoxy system" to be. But my gut tells me it is any epoxy system with high mix ratio of like 4:1 or 5:1.

What I found most interesting was that 2-part polyurethane paint holds out moisture better than polyester resin!

Now we must take this study with a grain of salt. For paddle craft that don't stay constantly in the water, the importance of moisture exclusion decreases a bit.

But bottom line: for the best protection, you can't beat epoxy.

Posted: Tue Sep 25, 2007 3:13 pm
by hairymick
G'day Matt,

As you know, I am a West Systems user now and swear by it. I have found that these people are passionate about their product and the people from West who I deal with here in Australia really do care about you achieving your goals in build quality and finish.

They have been a gold mine of information to me.

I would recommend using the 105 resin, coupled with 207 special purpose hardeners. This is what I use and I just can't see myself changinging to anything else, anytime soon. The stuff brings up allmost a mirror like finish with absolutely no ammine blush and is a pleasure to work with while wetting out. (but then again, I am an epoxy junky) :P

The other stuff they mention in their review may well work OK but to be perfectly frank, I don't care if the work or not. I put way too much effort into my boat builds to compromise them with an inferior product.

Posted: Wed Sep 26, 2007 7:07 pm
by Kayak Jack

I've used System 3 with good results too, but will not argue with either West materials or results. You feel as passionately about epoxy as I do about plywood. 4mm Okoume builds good boats - period.

Good materials won't guarantee a good end product, but poor materials can sure as heck guarantee a poor end product. The only chance I have is to use the best materials. My workmanship sucks, and needs all the help it can get.

Posted: Wed Sep 26, 2007 8:08 pm
by hairymick
G'day Jack,

Mate, I don't have access to many of the materials you do. There may well be superior epoxies to West but I haven't found them yet.

I would like to try some of the Raka stuff Matt recommends but don't have access to it.

None of the so - called premium epoxies that I have tried out here come anywhere close to measuring up to West.

With the service ATL composites provide, coupled with technical expertise and exceptional customer relations, I just can't go past them.

Posted: Wed Sep 26, 2007 9:33 pm
by Kayak Jack
I think West Systems are top notch materials. Stay right where you are. I just happen to agree with you about good materials. I do NOT want to go out away from shore in deep water in a boat made of the cheapest stuff I could find.

That's sort of like a guy working on tall buildings while wearing the cheapest safety belt he could find. A set-up for a Darwin Award.