I can't really comment on comparisons as I've never used epoxy only polyester. I do know as Chad commented that epoxy is expensive & polyester is much cheaper & in fear of repeating what Chad said poly does have UV protection which is prob'ly a good point as our boards spend a lot of time out in the elements. I've heard all the arguments for epoxy but I know & like polyester & it smells like........summer, sand, surf, bikinis (sorry I've drifted off....remeniscing)
Hi Folks - Just got my plans yesterday so I'm checking out the discussion. I've used epoxy for glassing for quite awhile building wooden sea kayaks and restoring an old white-water boat. Check out the Mas Epoxy website for a very understandable discussion ( www.masepoxies.com/public/index.cfm?fuseaction=articles.view&id=2240&publicationtype=Epoxy-School#24) . The big epoxy drawback is that UV breaks it down. Typically kayaks are varnished to protect the epoxy. Epoxy and polyester are suppose to be compatible once the epoxy has fully cured...I may try to use epoxy for laminating the cloth and then use the 32-737 Gloss Resin from fiberglass supply for the surface coating (on at test piece first of course) Varnish would be a pain in the butt on a board. Mas epoxies can be cleaned up with vinegar before they cure - depending on the mix they may take up to 5 or so days to fully cure.
Hi all, Just an update on my original post/question. My first board has been done for a while... I went with epoxy, mostly because it sounded to be a bit easier to work with than poly. It went fairly well, I really can't complain for my first try. So far so good as far as it holding up, but what I am now growing concerned about is the UV issue. I did not do any other coats other than the epoxy, which is not UV resistant, and from what I have seen on other sites, most HWS board makers will put up to 6 coats of marine varnish on top of the epoxy to give it UV resistance which keeps the epoxy from breaking down in the sun. After reading that, I think I may try poly for the next board...it may be a bit trickier to get right, but if you factor in all the extra time spent coating the epoxy, not to mention the added weight, it seems almost crazy to continue using epoxy if I plan on using and having these boards for a long period of time. I know one of the big selling points of epoxy is that there are not as many fumes to be breathing in, but varnish is some stinky stuff, so that's going to negate any of that. Let me know if you have any thoughts.
Post by vilanobeachsurf on Jul 23, 2012 17:27:50 GMT -5
Good question, speaking with other folks (that can't be vetted out) they keep saying that while epoxy will go wierd with UV, it takes a lot of exposure, and that their boards spend a lot of time indoors. Some say that additives can help UV resistance with epoxy but are they just selling?
While I was originally all set on Epoxy, now I'm not too sure that my environmental concerns with poly will overrule concerns about the epoxy gettng yellow or separated from the wood.
And 6 coats of spar varnish? I don't think so...
Glad to hear someone else talking about these concerns, it will be a couple of weeks before I have to make a decision. Thanks!
I read about the varnish part in another forum....Tree to Sea. It sounds a bit suspect to me as well...but apparently, that's what people will do with wood kayaks and boats to get a good shine as well as the UV protection and the people posting about it sound as if they have been doing it for years. Even if it does work, it seems like a whole lot of work, which is fine if you have the time and desire, but there must be a better way. And yea, I have heard that it takes a good amount of sun exposure to to cause problems with the epoxy, but I am one of those people that wants to make sure the thing will hold up as best as it can, after all the glassing part is probably the least desirable for most of us....and who wants to redo it because of overexposure to the sun, even if it is 5-10 or however many yrs down the road. As for the additive, I don't buy it...I am sure it does something, but probably not as much as would be needed...and adding more "stuff" to epoxy makes me a bit nervous when it comes to it burning into the coat below it. It sounds like you are n the same boat as me....what to do, what to do. I do think I am going to try poly for the next one, the last one was my first glass job, so I am certainly to committed to either method, I figure now would be the best time to experiment a bit before I do get used to a certain resin type and brand.
The varnish should be easy, use a H/F 20 oz gun ( $18.00 ) and let it get sticky between coats...3 medium wet coats and let dry. I will be using so automotive 2-part clear that is forulated for the Florida sun, as I have some left from a touch-up job and it does not last long once you open the can to moisture.
I prefer epoxy as I believe it bonds better with wood. I know of several builders who laminate with epoxy and gloss with polyester as the poly gives a better gloss and polishes well. I have primarily used Raka Epoxy or Resin Research Epoxy, both with excellent results. I am curious about the Aeromarine Epoxy advertised on this site. Has anyone had experience with this brand? Ray Maltby
I use epoxy and my last coat is a medium, then light coat of Rubber-seal Automotive Clear..... nice flow out easy to wetsand and buff to a super shine........................ Cut down on the sanding which I hate !