Best marine epoxy?

dorsett59 · Jul 18, 2013

My 1959 Dorsett Catalina has some wood rot. All six wood stringers are showing moderate to bad rot, and the transom is also getting soft.
I was hoping this would not be a major project, but it sure is one, now.
So, after I cut out the old stringers and transom, I will need to lay in new ones. I'm looking for recommendations on what marine epoxy to use.
Any recommendations? Anyone have a good/bad experience with any of them?

Thanks in advance.

Woodonglass · Jul 18, 2013

Re: Best marine epoxy?

There's no reason you have to use Epoxy. Your boat is made from Polyester resin and you can use it to do the repairs. Most of the members here on the forum use Poly instead of epoxy due to the fact that epoxy is about 30% more expensive and some people develop allergic reactions to it. The first link in my signature below has some good info on what you are about to undertake. I have also attached a PDF file for you to download and view with some good info as well.
(Click the Pic to download and View the PDF File)

View attachment MaterialsList.pdf

dorsett59 · Jul 19, 2013

Re: Best marine epoxy?

Thank you for the info. I've heard for a few sources that the poly isn't as water resistant or as solid as the epoxy. Also, since I'm doing this in a garage connected both to my place and the upstairs neighbor's place, fumes from the poly are going to be in both our living rooms. Of course, epoxy still stinks....

GWPSR · Jul 19, 2013

Re: Best marine epoxy?

Epoxy stinks FAR less than poly. I use no mask at all while laminating.

I have used both West Systems and US Composites epoxy. Both work well, but the US Composites is significantly less expensive than West, and USC does not add a hazmat fee to epoxy shipments, unlike poly.

Bondo · Jul 19, 2013

Re: Best marine epoxy?

Ayuh,.... While I completely Agree with WoG's stance on poly,....

Other than the Cost factor, I use epoxy more often than not,...

West system locally, 'n raka.com for bulk,...

Woodonglass · Jul 19, 2013

Re: Best marine epoxy?

Yep, the reasons you stated are very valid. USComposites makes some good epoxy. It requires a bit more "Baby Sitting" especially on vertical layups and does take longer for cure times.

metriccrescentwrench · Jul 19, 2013

Re: Best marine epoxy?

"Best" epoxy is pretty wide open. The best I've ever used is made by MGS in Europe, it's a dream to work with because of it's low viscosity and ease of wetting out glass fabric, but it's way too expensive to justify using on a boat. I like West Systems a lot, but lately I've been using US Composites epoxy as it's more affordable and is perfectly adequate for boat repairs.

Besides the reasons already mentioned for using epoxy instead of polyester resin (much better water resistance and stronger) epoxy is more suited for repairs as it forms a much stronger secondary bond than polyester resin (a 'secondary bond' is when you bond new material to old).

jigngrub · Jul 20, 2013

Re: Best marine epoxy?

I like the USComposites 635 thin medium 3:1 mix, it's tougher than train wheels!

sheboyganjohn · Jul 20, 2013

Re: Best marine epoxy?

I have been using areomarine epoxy but since I have not used any other epoxy I have nothing to compare it with, but its another option for you.

Woodonglass · Jul 20, 2013

Re: Best marine epoxy?

It's my understanding that there are only 3-4 MFG's of epoxy in the U.S. I believe West Systems makes their own I KNOW USC does not and neither does aeromarine. They buy it and label it. ondarvr, an iBoats member, is a factory rep and has been in the business for over 40 years and has made this statement several times here on the forum.

jigngrub · Jul 20, 2013

Re: Best marine epoxy?

Woodonglass said:
It's my understanding that there are only 3-4 MFG's of epoxy in the U.S. I believe West Systems makes their own I KNOW USC does not and neither does aeromarine. They buy it and label it. ondarvr, an iBoats member, is a factory rep and has been in the business for over 40 years and has made this statement several times here on the forum.

Which would mean most are basically the same... except for the price, which is where USComposites really shines.

Best marine epoxy?

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