Varnish problem/Sunday evening rant.

[Ben]

So, I have been cruising along on my Freedom 17-9 since mid-August, trying to get it (my 1st) done before ice-out, typically mid-April. I am currently ready to install the decks, the seats and thwart are temporarily installed, and the yoke and outwales are ready to install once the decks are in. Last Sunday, I used Epifanes thinned 50/50 with their spray thinner on the underside of the decks, and the inside of the hull under where the decks will sit. My plan was to put 2 or 3 coats of varnish on before installing the decks. As of tonight, 7 days later, the hull is still sticky! The canoe is in my basement, roughly 65 degrees, and the humiditity isn't bad as it has been a dry spring. It is far less sticky tonight than Friday, and it appears that it should be dry by tomorrow evening. However, I am worried about what is going to happen when I varnish the hull. I have 3 potential concerns:

1) Blush. I did not notice any, but I did not clean the surface with detergent before sanding and varnishing.
2) Thinning. I now know that I should not have thinned to 50/50 for varnishing over the epoxy, but could this make such a big difference?
3) Incompatibility. Any experiences using Epifanes over US Composites epoxy?

Have any of you had this happen before?

Thanks!

[Patricks Dad]

why do you think you should not have thinned it? I think you should definitely thin it for the first few coats (as described by the manufacture).

[Snowman]

I have used Epifanes over US Composites with no problems. I did not thin.

[Rick]

Usually the first varnish coat is slower-drying than the remaining coats... maybe some additional drying time is needed. It's probably better to thin at first and then thin less with each additional varnish coat. With Epifanes, I thought the recommended thinning was 10%... I used Interlux Schooner instead and thinning did help with brushing on thin, dripless coats.

Varnish that's too thick may tend to run and drip, because it cannot be brushed out thin enough to prevent runs. Some have used rollers to help prevent runs. Myself, I haven't tried this yet although rollers do help with getting epoxy on thinly and evenly with fill coats.

[Ben]

why do you think you should not have thinned it? I think you should definitely thin it for the first few coats (as described by the manufacture).

I have read in the past week in several places that Epifanes should be thinned to 50% when used on bare wood. I am making the assumption that this does not need to be done over epoxy. However, I called Epifanes this morning and described my process and problem. They said it is a common problem when you have amine blush, and I either need to remove the varnish, or let it cure on it's own. For the rest of the boat, I need to clean it with acetone or laquer thinner, then soap and water, then sand.

The varnish is very close to being dry, so I will let it go for a couple more days and see what happens. I will also thin the first coat to 50% over the epoxy as that was not the problem.

[Tom in MN]

I am going with blush as your problem. Always wipe down epoxy with some soap and water and then again with some clean water before varnish. It is really, really cheap insurance against blush reacting with the varnish. Blush is water soluble so I would stay away from the organic solvents you mentioned, especially if you already have a coat of varnish on the boat.

[Ben]

I am going with blush as your problem. Always wipe down epoxy with some soap and water and then again with some clean water before varnish. It is really, really cheap insurance against blush reacting with the varnish. Blush is water soluble so I would stay away from the organic solvents you mentioned, especially if you already have a coat of varnish on the boat.

The only varnish on the boat is in the bow and stern under the decks. I would like to stay away from solvents if possible because I am working in the basement and the ventilation isn't the greatest. I had numerous complaints from the family when I cleaned the boat with laquer thinner before fiberglassing.

[Rick]

For the rest of the boat, I need to clean it with acetone or laquer thinner, then soap and water, then sand.

If the epoxy is not completely cured, acetone or lacquer thinner could turn it a translucent milky white. I've had this happen on a paddle after only a day's cure time.... the epoxy had to be sanded off since the dark wood tones in the paddle no longer came through.

I'd much rather use water to remove dust from epoxy rather than strong solvents, unless the epoxy is going to be painted over.

[Ben]

Rick,
The epoxy has been curing for 2 months, so it should be finished by now.

As of last night, the varnish was still tacky and I lost my patience. I stripped the varnish off with acetone, washed with soap and water, and rinsed. I am going to revarnish tonight. This has been a good learning experience, but I am frustrated by the 2 weeks of lost paddling time.

[Ben]

ARGHHH!!! 22 hours after the re-varnish it is still tacky. Any other ideas? The varnish is drying just fine on wood.

[Glen Smith]

Try to warm the shop to 75 to 80 degrees to accelerate the drying. If that doesn't work, you have a compatibilty problem.

[Ben]

Try to warm the shop to 75 to 80 degrees to accelerate the drying. If that doesn't work, you have a compatibilty problem.

Glen,

I was afraid someone would say that. Do you have any experience putting on a barrier between the epoxy and varnish? Maybe a coat of high gloss poly, then varnish as normal? Is there a different brand of varnish that you would recommend?

[Glen Smith]

I have never used US Composites epoxy so I cannot recommend a varnish. I use Epifanes on my boats whether I have used West System epoxy or a local product (Citadel).
The only problems I have run into with Epifanes is a three day drying period for the first coat even with the temp up to 70. Subsequent coats dried normally.

Edited: I dilute Epifanes by about 10% for all coats. I use the Epifanes thinner only.

[Ben]

Last night the second try on the varnish was still tacky. I decided to do a test. I prepped a small section in the bow and stern, and applied straight (unthinned) varnish. I set up a space heater on the stern, and let things sit for about 20 hours. The unthinned varnish is hard as a rock on both ends, and the thinned varnish is still tacky. I will strip the hull again tonight, and try this again with no more than about 10% thinner.

[Glen Smith]

Are you using Epifanes "brushing thinner"?