varnish over epoxy resin

[Guest]

Can anybody help? I want to apply 2 coats of epoxy followed by 5-8 coats of varnish over my mahagony cockpit. Is this reasnable has anybody had any bad experiances with yellowing of any other problems? Is there a better way?

Thank you in anticipation

Ian

 

[wrr]

A previous owner did this. The epoxy eventually cracks locally due to timber expansion and contraction but is very difficult to remove completely. A far better option is solvent-based epoxy e.g. Eposeal by SP resins. This penetrates and primes without building up an external coating. It seems to stabilise wood and does not flake. I have used it to good effect on a hatch trim that used to shrug off varnish at the slightest whim. If you visit the US Wooden Boat forum, you with get the impression that all North American boats depend on the application of a Mr Smith's penetrating epoxy which seems to be a comparable product.

 

[PBrooks]

Yes, I would second WRR's comments - if there are any joints in the wood, then the epoxy may crack with expansion / contraction at these joints (if there are no joints, then epoxy would be fine - just make sure it has at least 2 weeks to go off completely and that you've sanded it flat).

On the alternative, CPES from Smith in the USA, I have used some of this and so far it is very good as a primer - it bonds to varnish and prevents water getting between the wood and varnish. It is also excellent for restoring wood that's gone soft. The SP systems product may be similar (though Smith claims his product is second to none and made "differently" from other epoxies in solvent). However, it's likely to be a lot cheaper than CPES. (I bought the CPES from Sweden and v expensive it was too - but you can have the sellers e-mail address if you want it though). SP systems have a good help line for this sort of query.

Good luck
Paul

 

[JOHNBOY]

I'v gone one step further with my forehatch and have epoxy sheathed it with woven glass mat..... But now I need the answer to your question .. What to over coat it with. We need hight uv filter varnish. But which?

 

[ccscott49]

I'd use a two pack polyurethane, first. Or a single pack polyurethane. Lots of coats=more UV resistance.

 

[Adrian_Morgan]

Forget epoxy. Try UCP (Universal Clear Primer) from International. Thinned, a touch to penetrate, perhaps two coats, then as many coats of Epiphanes; Ravillak or some high tung oil varnish with UV inhibitors. It's the business.