Epoxy under varnish and bottom paint

Sven

Sven

Seglare
I've worked a little with epoxy and FRP (FG over plywood on my small homebuilt speedboat as a kid and various small epoxy jobs) but I really don't know anything about it.

Reading various articles all over the place and on the West Systems pages, I get the impression that exposed wood surfaces really should be sealed with epoxy and then have a few coats of varnish on top. Any other solution is less dependable and more work. Similarly, bottom paint should be preceded by a couple of coats of epoxy before the paint.

Right now I'm won over by the rather convincing testimonials but I'm wondering if I'm missing less well funded counterarguments ?

Any balanced pro-con articles related to epoxy ?

Thanks,


-Sven
 
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Emerald

Moderator
My only thoughts on the epoxy/varnish combination is that epoxy can be a real pain to sand to that mirror smooth you might want your varnished surfaces to have. Also, make sure your hardener is fresh, or you might impart an amber hue. In general though, I think sealing dry wood with epoxy and topcoating is a very good approach to longevity in the marine environment, be it backing pads around a through hull or even bright work, if you're up to the work :egrin:. Dry wood is key to have it all work. Ask me how I know.... :cool:
 
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Dave Hussey

Member III
I learned the hard way that epoxy alone does not stand up to UV. The varnish overcoating is recommended for that protection.
I had created the prettiest finish on my tiller with epoxy, but after a summer, it all went to hell, and I had to re-do it. I also learned it is a lot easier putting epoxy on, than it is taking it off :egrin:
 
CaptDan

CaptDan

Member III
Sven said:
Any balanced pro-con articles related to epoxy ?

Thanks,


-Sven
Click to expand...

Not an article, just an opinion:

Depends on which flavor. I'm a big fan of Smith's Penetrating epoxy on exposed/prepped mahogany or spruce surfaces, but for oily woods like teak - not so much.

Smith's is an excellent primer, providing a tenacious foundation for varnish. I re-coated our old ketch's spruce spars, applying two applications of Smiths under 10 coats of Epiphanes. The finish lasted for years without breaking or peeling.

Capt Dan G>E35II "Kunu"
 
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tenders

tenders

Innocent Bystander
As usual, the hard-working Gougeon Brothers in Wisconsin are way ahead of most everyone on this.

There is a West System hardener with a UV protector that is specifically designed to be the base coat for varnish--207 Special Hardener.

http://www.westsystem.com/ss/varnish-over-epoxy/

I think that super-runny Smith's Penetrating under 207 under varnish would be a 10-to-15-year coating combination.
 
Sven

Sven

Seglare
tenders said:
There is a West System hardener with a UV protector that is specifically designed to be the base coat for varnish--207 Special Hardener.
Click to expand...

That was actually what made me ask. I've been watching the video tutorials trying to get a feel for how useful the 207 would be.

I think it was the tutorials that stressed how the wood has to be dry or the impermeability of the epoxy would work against you, promoting faster rot. At one point it seemed as if you would not want to epoxy something unless you could get to all sides and seal them but later they suggested undercutting any attached wood 1/4" so you could get some epoxy in under the edges.

I think I will try the 207 I have on the new hatch frames - two coats, with Epifanes on top.


-Sven
 
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P Abele

Member II
When I refinished our cabin sole, I used West epoxy (207 I think) on all surfaces and then varnished over the top. I left a post on this site about the nightmare of the waxy buildup on the surface of the cured epoxy which caused the first coat of varnish to not set up and then need to be striped and the surface cleaned etc. This new West product may have addressed that problem, but the moral of my story if to be very careful of surface prep before applying any finish over an epoxy surface!
 
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