Epifanes Clear Varnish

[ensign001]

I haven’t been able to achieve a completely smooth finish with the Epifanes Clear Varnish. I am getting what first appears to be a beautiful smooth finish until a closer look reveals very, very tiny raised bumps. These bumps are about a ¼” to ½” apart and can only be seen when the light is just right, but you can feel them. They don’t seem to be dust particles, but rather tiny air bubbles lifting the surface of the varnish. It seemed to start on the 8th coat. I wet-sanded the mahogany coamings and mahogany-veneer cabin doors using 400 grit paper. I rinsed well using a sponge to lift and remove the residue. Once dry, I vacuumed using a soft brush attachment. I used a medium mesh filter as I transferred the varnish to a clean, plastic container. I applied the varnish with a badger brush. As the varnish is going down it looks completely free of any air bubbles. The bumps appear after the varnish has dried for about 6 hours or so. I went through the same procedure for the 9th coat except I let the material dry longer and I wiped down the material with rag dampened with Epifanes Brush Thinner and then vacuumed the surface 2 more times before varnishing. The finish seems so close to perfect that I hate to accept these results particularly after spending weeks building up the coats of varnish. What am I missing? (I hope you don’t say a sprayer) These bumps are so tiny, is it possible to buff them off somehow without ruining the finish?

[Rachel]

Edited to say: I was using Epifanes gloss varnish (the classic formula), on trim pieces that I had removed to a shop for varnishing.

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I had a problem similar to this when I was varnishing the exterior mahogany trim pieces on my Monty 17. Even though I read around the various books and articles I could find (this was pre-forum), I just couldn't figure out what was going on. I keep trying harder and harder to make sure it was dust free, to no avail. I'd always come back the next day to find the tiny "dust motes" in the surface. I was straining the varnish, using a clean, high-quality brush -- the works. Coat after coat would present with the problem after it cured, after which I would sand with a fine grit, tack off, and try again.

Finally, I somewhere ran across the idea that it could be bubbles forming because the wood was heating up after I applied the varnish, thus outgassing (which you wouldn't think it could do through layers of cured varnish, but apparently it can). In my case I was using a varnish room in someone's shop in winter and so I was turning on a space heater when I was there.

So I made sure the wood was cooling down, if anything, after the varnish was applied, and Voila!, problem solved. And by that time I had twelve coats on everything (vs. the eight I had planned). Oh well, it looked great :)

So, there's one possibility.

Rachel

[Hirilondë]

I had a similar problem with Epifanes Rapid Clear. Feathering back over each area a minute or 2 after application and doing the coats during stable or declining temperatures did the trick.