The only remedy is to sand out the bubbles and apply another coat of finish -- more carefully this time. Apply the First Coat of Polyurethane. Quick link too easy to remove after installation, is this a problem? Polyurethane, in my experience, is both harder and tougher than traditional varnish. If these are dust bumps I would think you could control that on something small like a basket by applying the varnish and then putting it in some sort of enclosure to keep dust away. We have created these special content collections organized to give you a deep dive into a range of topics that matter. Mike Pekovich has a sled for each job: a sled for cutting dovetails, one with a sliding fence for box joints, a sled with a lower fence and stops for cutting dadoes, one with a tall fence for cutting tenons, and a dedicated sled for mitered boxes. In general you don't just sand, you then polish the surface. Shellac has the unique ability to block troublesome wood contaminants and still be compatible with any finish applied over it. Both activities introduce bubbles into the mixture in the can, and it's likely that you'll transfer some of these to the surface you're finishing. *I believe Bartley gel varnish is a polyurethane, but I'm not certain (can's at home).Dano, I'm afraid I must disagree regarding relative hardness. If it doesn't soften, it's some type of curing finish, such as polyurethane, varnish or tung oil. You can easily get anything from a subtle satin to full matt depending on the coarseness of the abrasive used (powdered pumice, fine grades of steel or bronze wool, Scotch-Brite or an equivalent). By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. The three thick coats let me be really aggressive with the polishing. Quick Tip! Polyurethane Book Case is Rough, Sand in Place? Apply more finish when you've leveled the drips out. Have…. Subscribe to Fine Woodworking today and get our lowest price of the season - only $20 for one year. What can I do? @grfrazee, yes, most any brown paper from wrapping paper to paper bags will do it. Is it illegal for a police officer to buy lottery tickets? That is just abrasive enough to remove dust and smooth the surface without removing any significant amount of varnish, and is a lot easier than rottenstone or other more traditional polishes. Or is it? It was beautiful-- for about 6 months. Chris Schwarz has worked out of his tool chests for decades, and finds them to be the perfect combination of protection, access, and flexibility. Recently, I am experiencing drying problems with the oil based poly, in which I have cause to blame the company for changing the formula (to meet upcoming standards). The floor and work area needs to be thoroughly clean as well. Clean the surface with detergent and water if it has been waxed. If I scrape them off, they're polyurethane chunks. FWIW. © 2020 The Taunton Press, Inc. All rights reserved. A: Are these lumps 'debris' or pimples? Shellac is a lot harder the poly varnish, which is softer even than "traditional" short oil varnish.Polyurethane is added for the purpose of "toughness", which is a lot different than "hardness". Note: wiping on varnish can nearly eliminate problems with dust nibs (also brush marks, runs and drips). That causes the finish to become pockmarked with little craters called “fish eyes” that are easily mistaken for bubbles. It isn't difficult to avoid making them in the first place -- it just takes a gentle touch when stirring the polyurethane and dipping your brush in it. - I've been careful not to paint the polyurethane on, and go over it once at the end in strokes that span the length of the piece. However, there is a way to remedy these flaws without undoing a day's work. *I also just wonder if in the long run using a more flexible varnish like marine spar would be better for your baskets. Also does the technique vary for gloss vs matte/satin? A: It sounds like something is reacting…, Q: I put a final coat of polyurethane on my wood floors and noticed that I missed a spot where my roller didn't overlap in application after the floor completely dried. I would be surprised though, if the shellac wouldn't crack with that test.I too don't care for gels. Next, brush on a couple of coats of dewaxed shellac, such as Zinsser’s SealCoat. Now it's an ugly, grey, worn floor. Guess I must be a little behind, I have never heard of it. 8. So I best not try to answer that question.Since you are 100% positive that these air bubbles appear as it is drying after following my previous suggestions, I can't answer that one either since I have never experienced this phenomena.Aside from the obvious differences in the compounds, the main differences between varnish, polyurethane, and shellac would be in hardness and drying time. This happens to floor finishers who drag the finish applicator aggressively and then must stay off the floor until the finish dries.