Richard Oedel replies: When you say “exposed to water” exactly what do you mean? If it is inside a boat, that differs from a dining room table which in turn differs from a kitchen table or a bathroom environment. Each of these could use a different finish. And what are your capabilities—can you spray? Are you limited to very low VOCs? Are you good with a brush?
For kitchen or hard family use with no regard for what goes on it, I use a two part catalyzed clear finish that is sprayed on. Various types exist, and I’ve used the Ilva system as well as ML Campbell’s products and have tested several others. I like the ML Campbell, because I have used it so often, but the Ilva is preferred by my friend across the street. They tend to have a thicker film coating so they tend to look more “plasticky” than some. I tend to use them diluted 20% so that the film is thinner.
If you don’t have spray equipment and want to brush, Behlen/Mohawk Rock Hard Tabletop Finish works well but is more difficult to apply. I also like the Epifanes product and use it more often. Like most of these finishes, do a lot of samples until you get the look you like.
If that doesn’t work for you, a urethane finish can be used. But I take it one step further to make it easier. With an oil based, quick dry urethane, dilute it 50-50 with Naptha and rag it on always working from a wet edge. I apply it with a paper towel with no texture on it—think blue shop towels or hard surfaced wipes. Apply it quickly and let it dry completely before the next coat. Spot sand with 320 and tack cloth if you need to get nibs off before the next coat. Six coats over three days gives you a nice look.
Dan Wallace replies: While there are several products on the market that offer protection from water exposure, I’m not sure anyone could be labeled as best. All have their own reasons for not using one over another. For instance, you don’t want to spray or you lack the equipment to properly apply, it causes yellowing when applied to light woods and a plethora of other reasons.
That being said my absolute go-to for ultimate protection is conversion varnish. Not only does it protect very well when around moisture, it resists heat, solvents and chemicals. It dries very quickly so a project can receive the required coats in one day. The downside—not easily repairable and it must be sprayed.
Second on my list would be Waterlox, especially when I am working with cherry or walnut. Waterlox has an amber tone to it so will “tint” the wood but in my opinion, it enhances the look of dark woods. Waterlox is very easy to apply with a quality brush or it can be wiped on. I generally thin it a bit when wiping as it flows and evens out nicely. Waterlox offers great protection against moisture and does well to resist scratches. One of its best qualities is how easy it is to repair—simply sand the area and apply Waterlox. I’ve had it on my countertops for the last six years with no issues.
Ted Blachly replies: I used polyester resin on some table tops in the early 70s and water has yet to get through that. It’s kind of thick and gloppy looking though—better suited for surfboards. We recently did three bar tops and used Zar Oil based poly satin. Three to four coats were brushed on without thinning. I liked the way it self leveled and had a short re-coat time. As with any finish, the touch and environment you are putting it on plays a big part in how it will look. There are a lot of other new products out there I have yet to try.
Bob Couch replies: The simplest finish for a table top that can be exposed to water is just a good quality varnish. Any water, regardless of the finish needs to be wiped up right away and not allowed to sit. One of the biggest culprits of water stains or rings from glasses is wax. Do not wax a table top—not even something like Pledge.
Even more durable finishes would be catalyzed or pre-catalyzed varnishes or lacquers. These are carcinogenic and require the use of spray equipment and a NOSH rated respirator. These are commercial finishes and are what is used on cabinetry and pre-finished flooring for exceptional durability.
Elliot Savitzky replies: I guess it depends on how much exposure you are talking about. If it will be an outdoor table that is a different story than a tabletop that occasionally has a glass with ice placed on it. I’m going to assume you mean a tabletop indoors. Most finishes will help protect but definitely stay away from shellac. Several coats of Waterlox or similar varnish, polyurethane or lacquer buffed out with a hard wax will help.
Garrett Hack replies: Marine varnish—a high quality spar varnish.
Al Breed replies: I often shellac the whole table and then finish the top with Epifanes Rubbed Effect varnish. Bombproof and looks good. Expensive but worth every cent.
Bruce Wedlock replies: The best finish for a tabletop that will be exposed to water are either oil or water based polyurethanes. My preference is General Finish’s Arm-R-Seal which is a thin wipe-on oil poly. This is much easier to apply than brushing thicker varnishes. I use the gloss to eliminate flatteners that require stirring. You can adjust the sheen at the end. Just apply it with a lint-free cloth wrapped around a sponge called staining pads. Small ones are commercially available at box stores.
Apply a liberal coat and then wipe off excess with the grain direction and allow to dry. This finish is on the thin side so don’t expect a fast build. Apply three coats with a light scuff sanding with 220 or 320 between coats to remove nibs. After several days of curing, wet sand the third coat with 600 grit wet/dry paper and water with a few drops of dishwasher detergent. This sanding should produce a white powder residue. If it doesn’t, the varnish hasn’t fully cured. Be patient.
Apply a final coat of Arm-R-Seal and buff with 4-0 steel wool or a light gray Scotch Brite pad (800 grit) and wax to achieve the desired sheen. An excellent YouTube demonstration is youtu.be/Y7jvnM2PX0E.