Problems with varnish over epoxy!

[prohandyman]

Well, all was going good with wood stripped tear until.....
Applied first coat of spar varnish over top of cured epoxy! It has been 7 days today in 72 deg. shop since coat...and it is still sticky! It is supposed to be dry to touch in 6 hours, sandable in 24. Product was mixed well, which is critical. Called manufacturer of varnish (McCloskey/Valspar). It appears that there has been several problems over last couple of years with this varnish applied over West Systems brand epoxy. Some kind of bad chemical reaction.
NOTE: neither appears to be bad products.
Just don't use together!
West System epoxy says Z-spar is their best choice, or System 3 (which make both epoxy and spar varnish) I have used MAS-90 epoxies before, with Man-O-War varnish, with no problems.
So, guess what I started doing today?? Wiping down the entire exterior with mineral spirits to remove uncured varnish. With a lot of effort, it is coming off, back down to sanded epoxy.
If you are going to varnish over epoxy - do not use these two products together!

[doug hodder]

Dan...so when you get it all off how does the epoxy look? Has it been effected in any way from the Varnish, IE gummy, softened, lifted or removed in any way? Did you use the 207 hardener?

I just went out and mopped the side of mine with a rag soaked with acetone. It didn't touch the epoxy that was cured for a couple of weeks, it did soften the stuff I just put on a couple of nights ago however. After outgassing the actone, it was fine, the difference was that the sides have the UV hardener and the stuff that got softened was regular construction catalyst. But the acetone is a lot "hotter" than a varnish.

How much cure time did you have on your sides prior to the varnish? I'd think that if there were a reaction between the 2 that the epoxy should show some changes also.

I've got no answers for you, just trying to help trouble shoot the situation. I've never used Varnish over it, but I know it's been done in the wood boat industry. Might be an idea to call West tech guys and don't mention any brand names, just ask if they've ever heard of anyone that has had a reaction between varnish and their product, see what they say. Doug

[Juneaudave]

Don't you just hate it when stuff like that happens. I've never heard of that with that particular combo, but it is too common. And it's really hard to troubleshoot. Was it the varish, the interaction of the vanish and epoxy, or my favorite of all times....the tack rag. Try that varnish over a plain piece of wood...first following the procedure you used to prep...then just the varnish right on the wood without a wipedown of a tack rag or mineral spirits. I can't believe it is an epoxy/varnish interaction. Geeee

[tonyj]

Maybe old varnish?

[prohandyman]

Good questions
Doug
The epoxy looks just like it did before I applied varnish. Hard, sanded, ready for varnish. Thats make me believe that it wasn't a chemical reaction. Cure time on epoxy was about 30 days. I did call West Sys and they also had never heard of the problem, but did suggest Z-spar varnish as a good choice.
Dave
I did try the varnish on bare wood and it dried fine. There was even a spot on the sides with epoxy that dried fine. Whats really wierd it that it was the third call into McCloskey/Valspar to a third different CSR that even mentioned a chemical reaction possibility. All three asked the customary questions like temp., humidity, cure time, prep, etc. The CSR even stated a specific case of a customer using the same varnish on the same epoxy on 150 canoe paddles and they all stayed in a tacky state, and he eventually had to remove all the varnish, just like i'm doing.
tonyj
I too think it might have been old varnish, but that doesn't explain the fact that it dried an bare wood.
The manufacturer and the dealer have stated that they will refund my money on the varnish(if I can find my reciept)
Postscript
Maybe it was meant to be - the varnish was SATIN - I really wanted gloss or semi-gloss, but I didn't notice that fact until I was applying product, and I just conceded that satin would do!!! Did I somehow conjure up the power to self distruct?

[DBizer]

Dan,
This answers my question. Or makes it even more of a question! I varnished over same epoxy with spar varnish also. I had about a pint of the McCloskey/Valspar product left from another project, used that up (being frugal!!) then I finished off the first coat with Man-O-War. Where I put the first stuff never dried!!!!! The rest, where the Man-O-War was used, dried fine. I blamed it on myself for using old varnish. Stripped it off with paint thinner then wiped it down with acetone. Then I coated the area with the Man-O-War and everything worked out fine. Now I am wondering if it was old varnish or a chemical reaction? I don't have any of the McCloskey left to try it on bare wood. I'm curious to know if others have had similar results.

Hope it works out OK for you! Mine has three coats now and all is well!!!

David

[Miriam C.]

I too think it might have been old varnish, but that doesn't explain the fact that it dried an bare wood.

Perhaps the bare wood allowed it to soak up enough to make a difference

[Alphacarina]

I too think it might have been old varnish, but that doesn't explain the fact that it dried an bare wood.

Perhaps the bare wood allowed it to soak up enough to make a difference

I think that's the secret

There are several things which work well on wood but will never dry on glass, rubber or epoxy - I assume because the petroleum distillates have nothing to soak into and once the surface skins over, they can't evaporate either

Don

[Jst83]

Postscript
Maybe it was meant to be - the varnish was SATIN - I really wanted gloss or semi-gloss, but I didn't notice that fact until I was applying product, and I just conceded that satin would do!!! Did I somehow conjure up the power to self distruct?

Yep I fully believe that's possible, reason for everything
Now you can get it the way you wanted at the start.

Now I'm sure there's a reason I'm gonna have to strip paint and fix my cracks. Just not sure what it is.

Glad the epoxy wasn't harmed, That's a lot of beautiful work I was worried

[prohandyman]

Glad the epoxy wasn't harmed, That's a lot of beautiful work I was worried

Yea, I was more than a little worried too!. Applied new epoxy to a test area yesterday. Should know today if it works.

[schaney]

Hmmm, that sucks, at least it don't effect the epoxy.

I've been using Epifanes Marine Spar over West Systems 205 and 207 hardner for sometime and never had a problem. I normally let it cure at least seven days in 65-70+ temps. I have applied varnish in as short as two days over 205 and had no problems.

I'm actually doing some testing with Target Coatings Hybrivab, it's a new waterbrone hybrid alkyd varnish. I have a Okoume test panel sealed with CPES, then finished in Hybrivab out in the weather. So far it's holding up well just fine. It flows out great, 1-2 hours recoat time and water clean, how it works out as an alternative to normal marine spar.

[prohandyman]

Well, guess what? The new varnish(Z-Spar) dried perfectly, in less than 24 hours. So, was it actually a chemical reaction, or just a bad batch of spar varnish??