Prepwork for Topcoating Over Lacquer?
Issue: Issue 350
Posted Date: 4/29/2014
I currently have cabinets with a catalyzed flat lacquer finish, which lacks a strong durability, in the kitchen. My wife would like the finish changed but not lacquer. What is the best recommendation for prep and a good durable semi or high gloss clear? I lack the spray equipment so it will be done with a brush. - Mike Andrews
Chris Marshall: I would rub down the surfaces of those cabinets with #000 or #0000 steel wool or a fine-grit synthetic scrub pad to give the surface some "tooth," then topcoat with an oil-based polyurethane varnish. You can buy oil-based poly in both semi-gloss and gloss sheens. I've also used gel-type wipe-on urethane finish on situations like yours, because the thicker consistency is easier to control on vertical surfaces to help avoid sags and drips.
Tim Inman: First, clean the finish. Whatever you put on over the surface will only bond to what it touches. If you have wax/grease/oil, etc., then your new finish will not have a good bonding base. Second, be sure to scuff and feather out any places where the old finish is flaking off. You might consider overstaining to improve/modify/repair the existing color. Test. In an inconspicuous area, try the new finish of your choice. Does it bond? Does it blister the old finish? Does it dry correctly? Once the testing stage proves out, then go for it. Use the best brush your pocket will allow. I prefer a 2-1/2 inch bristle/ox brush. Real bristles, not synthetic! Follow the manufacturer's instructions, but barring that, I suggest thinning the first coat quite a lot. Often, I dilute the first coat up to 50 percent with thinner. Why? I want thorough uniform wetting of the new finish. I want it to go down into the little cracks and crevices to set up a new base. The second and third coats can be heavier, but I still opt for dilution. I can't overemphasize how much better your finish will be if you apply two or three thinned coats as compared to one or two thick ones. Works every time. What finish? Probably a solvent-based polyurethane would be my first choice, since you especially mention solvent durability in the kitchen. Gloss? Remember that the shinier the finish, the more it will reveal and magnify the flaws in the cabinets.