Years ago, I built a kitchen table out of ash. I finished it with what probably was the first generation of water-based polyurethane. My problem is: every time it gets humid, everything sticks to the table. I have wanted to refinish it numerous times but didn’t want to strip it. I read your article on the latest in water-based polyurethanes (“Water-based Coatings,” August 2015 print edition of Woodworker’s Journal) and was wondering which would be the best? Can you recoat with oil-based over water-based? The current finish is a low-gloss satin. What prep work would be needed? – Charles Bradley
Tim Inman: Do yourself a favor and strip that old crummy finish off. Start over with a fresh clean surface. Otherwise, you’re building a house on a foundation of sand. It won’t work to just put new over the old, and you’ll have an even bigger, nastier job to do when you decide to give up later on and strip it anyway. Pennywise, pound-foolish; never time to do it right, always time to do it over; marry in haste, repent at leisure … I could go on, but the point here is this: these old adages are common and they exist because of experience by generations before you. Do it right the first time, and you’ll be a much happier man in the long run.
Chris Marshall: And to that end of stripping and starting over, I would use one of the heavy-duty, gel-type liquid strippers you can find at home centers. The smelly stuff containing methylene chloride works quickly and effectively. But make sure to wear chemical-resistant gloves and apply it with plenty of fresh ventilation, because the fumes aren’t healthy to breathe. Or wear a respirator with vapor cartridges. The old finish should strip off pretty quickly. Then, I’ll make a suggestion for the next topcoat: General Finishes Enduro-Var. I say that because I’ve used it extensively for projects in the magazine lately — our Greene & Greene Bedstead and Nightstand projects in the February and August print issues both were finished with Enduro-Var.
Here’s why I like it: it’s a “next generation” waterbased poly that crosslinks with the air as it cures for a tough finish. It brushes on smoothly, levels out well when wet and dries quickly. I also appreciate that the finish has a slightly amber tint, which warms up the color of the wood. It will remind you of the color cast you get with oil-based poly. On a pale-colored ash table, it could look great to give the table a vintage heirloom look. And, of course, cleanup is easy with soap and water. I’ve also noticed that the clarity of the cured varnish is very pleasing. If there’s any figure to the wood, Enduro-Var will enhance it.
If you don’t like the amber tone and want to keep your table as blonde as possible, I’ve also had good luck with Rust-Oleum’s water-based Ultimate Polyurethane. It dries clear with very little color cast on blonde woods like ash and maple. Same benefits too: good leveling, fast drying, low odor and easy cleanup. I buy mine right off the shelf at Lowe’s.
With either product, I’d stick with a satin sheen as you’ve done already with your table’s current finish. Personally, satin just looks best to me on a handmade “utilitarian” project like a kitchen table. Good luck with the project!