Epifanes clear varnish not hardening

[hautamak]

I'm varnishing my canoe soon and made test with epifanes to small area of my canoe. It was sanded and had cured month before adding varnish. Now two weeks later it's still very tacky. I did not follow instructions about thinning varnish for first coat as I'm applying it over epoxy and not over wood. Thinning helps varnish to go deeper to wood as I understand.

what now? Should I use 2 component polyester top coat and varnish over it? Could it be amine blush? Any help is appreciated!

 

[Fitz]

Epifanes is notoriously slow to cure sometimes. I would give it another week and see if it cures. If not, I would try thinning with the recommended thinner 50% and try again, then 25%, then full strength.

Did you wipe the epoxy with anything before varnish?

Let us know how you make out.

Fitz

 

[Jim Dodd]

Sounds like the classic Amine Blush problem.

What epoxy did you use ?

Did you wash down the hull with water and Ammonia, before varnishing ?

What to do ! If it is Blush ? Remove the varnish and wash. You can wait and hope it dries. If it is Blush, eventually it will peel.

Jim

 

[alsg]

Coincidentally, I think I may be experiencing the same issue. I applied a first coat of Epifanes (thinned 50-50 with mineral spirits) over my gunnels and a seat frame that were previously epoxied with West 105/207 (which supposedly does not blush). It's only 24 hours, but the Epifanes is still quite wet. Brushably wet.

 

[stripperguy]

I once had an issue with Epifanes over RAKA epoxy on a sailboat I built
a few funky spots turned into a huge mess after a few days longer wait
My problem was as exactly as surmised above...amine blush
After scraping and sanding back down to clean epoxy I did a full wash with soap and water
The next Epifanes application went on flawlessly

 

[Cruiser]

My understanding is that "ALL" of the epoxies can produce blush under certain conditions. The epoxy layer is supposed to be wiped down with I believe soap and water (I am not going to check, but each manufacturer states this in the directions or website), to remove any blush BEFORE sanding.

If you think that sanding will remove the blush, that isn't correct, it will just get ground into the surface as you sand.

The blush contains compounds which will mess with the varnish chemistry and prevents it from oxidizing to cure.

Having said all this, I don't usually wash the epoxy before varnishing and I currently have a slight tack issue as well.

If you have the shop ability, the advice is to a) increase air flow (fan) and 2) if you can raise the temp, get it up (I took mine to 82F) ... leave it for a few days, if it cures you're done, if not, you have a mess to clean up. More air and heat will help with oxidation ... hopefully aiding your varnish to cure up.

As far as thinning, Epiphanes is a high solids varnish, which should always be thinned to some degree. Initial coats are usually thinned to help setup the first layer and provide a base for the build coats that come later. Also, with less solvents the varnish will tend to skin/set too quickly and you may end not getting a smooth finish without some thinning. I agree that you wouldn't use the regime for bare wood, but I usually thin 25% on the first coat and 15-20% there after. Just makes it easier to handle.


Brian

 

[Canotrouge]

^^^^ exactly what he said!! Epiphanes need to be tinned no matter the coat first coat more and last coat less but still need to be tinned! Low humidity environnement help a lot too!! Good luck!!

 

[Guest]

My understanding is that "ALL" of the epoxies can produce blush under certain conditions. The epoxy layer is supposed to be wiped down with I believe soap and water (I am not going to check, but each manufacturer states this in the directions or website), to remove any blush BEFORE sanding.

If you think that sanding will remove the blush, that isn't correct, it will just get ground into the surface as you sand.

Hopefully it is just an un-thinned first varnish coat, or temperature/humidity issue, and will eventually set up. If it is an amine blush issue topcoats pretty much never set up properly. Please let us know.

I have had amine blush issues topcoating epoxy with varnish, urethane and paint. All were ugly, and laborious to remove and start over.

West 205 Fast hardener is notorious for producing amine blush. But even 206 slow hardener over an uncured epoxy coat for a better chemical bond will amine blush. I have less experience with 207.

I use release treated peel ply on any epoxy work. Amine blush supposedly forms on top of the peel ply. Maybe so; I still wash the hull, lightly wet sand it and wash it again. After having to deal with amine blush and never-curing varnish or paint topcoats a couple times it just isn’t worth taking the chance.

Temperature and humidity likely play a part. The shop has a hi-low recording thermometer, and a hygrometer. Currently 75F and 69% humidity; it will soon be time to put the shop AC unit in the window.

I run a radiant oil heater under inverted hulls in cold weather when I don’t want to heat the entire shop; set on Low 600W the overturned hull nicely captures the heat. The shop may be 45F, but the boat stays 65F all night.

In humid summer weather I run the shop AC, as much for boat work humidity control as for me.

One more possibility – if you are using pumps with the epoxy, especially old pumps, it is worth cleaning them and checking the dispensing calibration.

https://www.canoetripping.net/forums...pumps-reprised

 

[Jim Dodd]

I once had an issue with Epifanes over RAKA epoxy on a sailboat I built
a few funky spots turned into a huge mess after a few days longer wait
My problem was as exactly as surmised above...amine blush
After scraping and sanding back down to clean epoxy I did a full wash with soap and water
The next Epifanes application went on flawlessly

I know RAKA makes and sells many epoxies. I use their 127 resin, and 350 Non blush Hardener. No problems with varnishes drying..

What hardener did you use stripperguy ?

Jim

 

[stripperguy]

Jim,
It was one of their 600 series hardeners, along with the 127 resin. It kept getting worse as the days went on, what started as a few "funny" spots, turned into many, many wrinkly spots, and eventually looked like some sort of marine leper. I'm sure it was entirely my fault...that guffaw set me back 2 weeks, as I couldn't sand the increasingly gooey varnish, and had to hand scrape every square inch of the hull. That thing was (is) 19'2" long with a 7' beam.

 

[Guest]

One more thing with West System pumps; the 207 hardener uses a 3 to 1 ratio, the 205 and 206 hardeners use 5 to 1 pumps. Definitely need to use the correct pump with 207.

 

[alsg]

I called Epifanes today and spoke to someone there who purports to be a technical expert.

He told me Epifanes cannot be mixed with the new "odorless" mineral spirits to thin and that they will turn Epifanes "to jelly." You have to buy their branded brushing thinner (which I gather is good old fashioned mineral spirits of the odoriferous kind).

He also told me you cannot put Epifanes over epoxy without washing for amine blush or it won't dry.. He specifically said this applies even to epoxies claiming to be blush free, including specifically West 105/207.

So, much sanding later (down to bare wood) I am waiting for some Epifanes brushing thinner to begin again.

 

[Cruiser]

Thanks Alsg ... most of that I had already researched, but the odorless mineral spirits info is new to me. I had turpentine and odorless spirits side by side, I only reached for the turps because I was low on the odorless stuff, I thought they were both OK, something learned, getting the odorless off the varnish bench.

Guess I had a lucky pick this time, thanks for the info.

Brian

 

[hautamak]

Thanks for help everyone!

I did wash epoxy with warm water and soap, then sanded and wiped with dry cloth. After those I applied 5% thinned epifanes, and now it seems to dry properly. I think it was amine blush..

How many coats you put on your canoes? Manual says 3 coats and then 4 extra coats.