Varnish over epoxy

[John Vigor]

Does anyone understand why Epifanes glossy spar varnish will not dry when applied over Three Systems epoxy resin? I have been caught this way several times now.

Is it something in the Epifanes specifically, or is it unique to System Three? I know it's possible to varnish over epoxy because there are plenty of kayaks finished that way--the varnish has the built-in UV inhibitors needed to protect the epoxy and stop it going yellow when exposed to sunlight.

What combination of epoxy resin and spar varnish actually works?

Cheers,

John Vigor

[Tod M]

Could there be some amine blush remaining on the surface of the epoxy? That might inhibit setup.

A green dish scrubby and water will remove it.

Dunno if that is the issue here...

[Jim Davis]

John

My wife is successful in using Epifanes Wood Finish over CPES after a good sanding. She does this on our big boat. Then after a base is built she shifts to their varnish for the final coat(s). On her kayaks, she uses regular spar varnishes over West/MAS/RAKA with no problem. I note from Epifanes web site that to use their paint over fiberglass it must be primed for adhesion.

My guess is Epifanes doesn't recognise epoxy or other modern resins.

[John Vigor]

Could there be some amine blush remaining on the surface of the epoxy? That might inhibit setup.

A green dish scrubby and water will remove it.

Dunno if that is the issue here...

No, Tod, no amine blush. I scrubbed the cured epoxy thoroughly with fresh water, and then wet-sanded it with 320-grit wet-or-dry paper.

It's something else, but I don't know what.

John Vigor

[Tod M]

on another forum:

"Yeah, books can be written about the quirks of resin/finish interactions. For the record, System Three makes a good one part spar urethane that is compatible with their resins. The manufacturer told me that "Z-Spar" and "Captain's" also work and that there was anecdotal info that Epifanes has had some problems. I've also heard that McCloskey's "Man O' War" works with System Three. All have UV inhibitors. Other resin systems.... I don't have a clue."


taken from http://www.myccr.com/SectionForums/view ... p?p=284277

Hope this helps,

Tod

[Bill Goldsmith]

West System has recommendations that could help. There is no mention of specific brands of varnish, however.

http://www.westsystem.com/ewmag/18/pdf/varnish.pdf

[John Vigor]

Thanks for the help, guys. By dint of extensive research on the internet, I have discovered that this is a common problem. Some brands of spar varnish are compatible with some brands of epoxy resin. But the makers of epoxy don't want to advertise which brands of varnish are okay to use with their stuff for various reasons, although if you call their technical staff they'll give you the brand names over the phone.

In general, however, it seems that you shouldn't try to coat epoxy with a traditional spar varnish until the epoxy has cured for at least two weeks. Then you should scrub it with fresh water to remove any amine blush and let it dry before applying the varnish.

The System Three epoxy company has developed its own brand of what they call "spar varnish" that is compatible with their resin, but it's a urethane and in any case I prefer Epifanes.

The good news is that my Epifanes will eventually dry. It might take two weeks, and end up like the carpet in a dog kennel after a fortnight of gathering dust, but it will dry. And subsequent coats will dry within 24 hours as normal. I hope.

Cheers,

John Vigor

[Len]

I would like to redo the sole of my 98 RH with something durable. What about putting polyurethane over the current varnish or some form of epoxy?

[Chris & Dale Schnell]

I have been highly successful in applying 3-4 coats of West System epoxy to bare teak and then following that with 4-5 coats of epiphanes high gloss varnish. There are several keys to success in this:

• start w/clean, dry, bare teak
  
  You MUST totally encapsulate the wood to seal it from water intrusion....otherwise it will eventually flake...toe/rub rails are classic examples where it won't work
  
  After applying a coat of epoxy, squeegy it into the wood, removing excess, for at least the first 2 coats, then start building coats.
  
  Of course you must burnish sand between coats of epoxy
  
  I use the epiphanes that allows you to apply the next coat w/i 72 hours WITHOUT having to sand between coats (there is a God of Teak afterall)

Again, my success has been ultimate when I've been able to encapsulate the wood....moisture is your enemy!

My Teak on my Boston Whaler Montauk was done 5 years ago, and I just do a lite burnish and application of 1 coat epiphanes anually and it looks like new!

[Tod Mills]

For a sole, I've heard good reports on two things, both non-skid:

Ultimate Sole: http://www.ultimatesole.com/

Gymseal Floor Finish: http://www.kellymoore.com/products/sundries_gymseal

[Bruce Bett]

Have any of you guys tried cutting epoxy with Xylene? This makes a very good penetrating epoxy. I've been using it to stabilize some rot in an old <a href="http://www.flickr.com/photos/13332788@N ... 22600/">St. Lawrence skiff </a> I've been restoring. I get good penetration with a 50% cut and then go to about 30%. I've been thinking about using it on my sailboat as well. (I'll start with the cockpit table). I'm thinking that if I get the wood good and saturated with epoxy the varnish topcoat may hold up better. Any thoughts?

Bruce

[Jim Davis]

I haven't tried Xylene, but I have had good luck with Acetone or Denatured Alcohol. My preference for penetrating epoxy is CPES. That said I have had good luck with Epifanes Wood Finish, not their Spar over the epoxy. I'm not sure if the old way of cutting varnish 1:1 with mineral spirits isn't as good, or perhaps a touch better. Perhaps the next time I have to go to bare wood I'll try the old way again.