Finishing Wood Restaurant Tables
You are a restaurateur with a busy dining room and a demand for ultra disinfecting procedures. You have played the role of designer, curating your restaurant space with furniture that gives people a unique experience and now that furniture not only needs to be cleaner than ever, it must be maintained. This is the time to step into the role of craftsman, to think like an experienced woodworker and care for those beautiful tables so that they can continue to be the centerpiece of the room.
We at Viridian can help you gain a little insight into what that means. Regardless of what cleaning agents you are employing in your space, it is important to keep in mind what sort of finish stands between the disinfecting agent and the natural character of the wood. While we typically use the most durable kind: Conversion Varnish, it may be the case that your table tops are treated with other, more delicate finishes. Our list below walks you through each kind of finish so that you can not only make better informed decisions on your chosen method of disinfecting but also learn more about how our skilled technicians create restaurant furniture with you in mind.
Conversion Varnish: In the restaurant world, conversion varnish is the gold standard for durable table finishes. There are many manufacturers of this type of finish, each claiming to be the most durable; most of them are indecipherable from each other once cured and there are many good choices. Conversion varnish is chemically cured, meaning that a second chemical called a catalyzer or hardener is added to the mixture to help cure the finish. The catalyzer sets off a slow chemical reaction that starts to cross-link or cure the solid materials in the finish to make it more durable. Conversion Varnish is typically 60% solids, while the remaining 40% is a solvent that is used to thin the solution enough for spraying. There are several ways to apply this type of finish, but it is typically applied with a spray gun in a spray booth. Spraying the finish gives a very even appearance and lets you control the build levels of the finish, allowing you to apply just the right amount. It is possible to use a brush to apply this type of finish, but it is not recommended because it can leave brush marks. There is no doubt that Conversion Varnish is the most durable finish for restaurant tables. The type of conversion varnish that Viridian Reclaimed Wood uses has been tested for compatibility with Ecolab’s most common cleaning agents that are used in restaurants. We’ve tested this finish against common bleach rags, alcohol, citrus, wine, vinegar, ammonia, mustard, and ketchup. We have also submitted samples of our tabletops for abrasion testing, all of which easily passed.
UV Finish: Ultra Violet (UV) finish is a relatively new finish to the market in the last 50 years. The technology behind UV finishes is fascinating, it is cured instantly with light! The finish is rolled or sprayed onto the surface of the wood tabletop and is passed under a series of very bright lights that produce various wavelengths of UV light. When the finish is exposed to these intense lights, it immediately transforms from a liquid into a hard solid. You may have seen this technology before in nail salons, some types of Gel nail polishes are cured with UV lights. UV finish is a special solution containing proprietary ingredients, but here are the basics. Instead of having solvents in a mixture like in a conversion varnish, UV contains 100% solids. This means that there is nothing to evaporate. This mixture of solid materials is combined with a photo initiator that reacts with the lights to cure the finish. One of the advantages to this type of finish is that it has no VOC’s, so it is very environmentally friendly. It is also a very hard finish that is resistant to many chemicals and abrasion. The down-side to a UV finish is that it requires expensive specialized machinery to apply.
Epoxy Finishes: We have all sat at a restaurant table that has a thick epoxy coat with coins or other fun items buried under the finish. An epoxy is similar to a Conversion Varnish, except it’s less resistant to the cleaning agents commonly used in restaurants. Epoxy is a two-part mixture that when mixed, sets off a chemical reaction that starts to cure the two parts together. The benefit of an epoxy finish is that it can seep into the smallest of cracks and voids, filling them up with the finish. When finishing reclaimed wood tables for restaurants, it is typical to make up a thin batch of epoxy and brush it on a rustic table top to help seal the small cracks; especially for barn wood tables. The last thing a restaurateur wants is a table that has not been sealed that can collect food and debris, creating an unsanitary condition. Once this thin epoxy layer is cured, a traditional conversion varnish can be sprayed on top to help create a chemical resistant finish that will be more durable. Epoxy creates a thick, durable top coat for tables with a rustic surface. The down-sides of such a thick finish are that it is costly, increases lead times for production and it can’t be repaired easily on-site. Another drawback to epoxy is that it can yellow over time.
Polyurethane: Have you ever sat at a restaurant table that was sticky even though it was dry? That is what happens when you put a polyurethane finish on a high-traffic restaurant tabletop. The reason the polyurethane finish fails so quickly is that the cleaning agents typically used are very harsh and break down this type of finish. Polyurethane was developed for flooring, not tabletops. Bleach and several common sanitizers will eat through this type of finish in a relatively short time, leaving your tabletops tacky to the touch; not a good first impression to your customers. Unfortunately, there is little to be done once the finish gets tacky. The best option is sand off the old finish and try to recoat the tops with something more durable.
Wax Finishes: Back in the old days before we had a grasp of modern chemistry, wax was the preferred finish for wood. It was readily available across the world and did a good job at keeping moisture away from the surface of the wood. Obviously, since this finish is so low on the list, we would never recommend it for a high volume commercial table top coat. Wax finishes need to be reapplied frequently to keep their luster and the level of protection. One benefit of a wax finish is that it can easily be repaired, just by buffing in more wax onto the surface. One of the biggest drawbacks, other than the durability, is that once you use a wax finish, you can never use another type of finish on top. Wax is a release agent, so no other finishes will stick.
Oil Finishes: The main finishes we consider when talking about oil are Tung oil, Linseed Oil, Teak Oil and Danish Oil. All of these oils are rubbed into the wood’s surface and allowed to dry for a day or so before re-coating. Oils are very easy to apply. They really bring out the grain of the wood and look beautiful. The downside is that they offer little to no protection from moisture or chemicals for the wood. We wouldn’t recommend an oil finish for an indoor restaurant application unless you are committed to re-oiling the tops regularly (possibly as frequently as weekly). We do, however recommend high quality oil finishes for outdoor restaurant tables. Hard film finishes like Conversion Varnish are not suitable for exterior tables that are exposed to the elements. They must be coated with a “repairable” finish like oil so that every year the tables can be refreshed with a new coat. Our favorite exterior oil finish for wood tables is Cabots brand. It is easily refreshed annually and offers excellent protection from the elements. It is also widely available across the US.
Nitrocellulose Lacquer: Not recommended as a restaurant table finish because of its lack of durability; something as basic as water glasses will leave rings on the table easily. This type of finish is also easily harmed by ordinary cleaners.
Shellac: Most people don’t know that shellac is a resin secreted by the Lac bug found in Thailand and India. The resin is refined into different grades and mixed with alcohol to dissolve the resin, which is then applied to wood as a finish. Shellac is a great sealer for several other types of top coats but is not a good option for a restaurant table. The main reason for this is that alcohol dissolves the shellac very easily. The other reason is that shellac is a brittle finish and not suitable for the heavy abrasion found in restaurants. It can be sprayed or brushed on easily and is a great finish option for low-traffic applications such as a dining room table at home.
Information on some of the finishes called out in this article can also be found on this Wikipedia page in a nice graph format that compares each of the properties of the different finishes. https://en.wikipedia.org/wiki/Wood_finishing