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Bowl Finishing

By

John Kerr

I am an unapologetic bowl turner. I have been presenting my work as functional wooden art at area craft shows and online for nearly twenty years. I have several repeat customers, as well as people who come into my booth and tell me that they purchased a bowl from me a year or more ago, and they use it every day. That is extremely satisfying to me. One of the main reasons that I prefer craft shows over online selling is that craft shows allow potential buyers to handle the bowls, which is important to me as I stress the functionality of the piece and my intent for them to be handled and used on a regular basis, thus the importance of the way that they feel. I am also a minimalist when it comes to finishes, preferring a low sheen that lets the wood speak for itself.

For several years I used a product called Deftoil, which gave me the look and feel that I wanted and was pretty easy to use. Unfortunately, the parent company was purchased, I believe by Pittsburg Paints, who promptly decided to cease production of Deftoil. This caused a bit of a stir online among fans like me, but someone had the idea to search and download the Deftoil MSDS, which revealed that a homemade imitation was actually pretty simple. The finish that I now use is a mixture of equal parts Minwax Helmsman Oil Based Spar Urethane (Lowe’s); 100% Pure Tung Oil (The Real Milk Paint Co. or Woodcraft); and mineral spirits. This results in a penetrating finish that is in the wood, not on it, and I use it on all of my pieces including those that are less functional and more display.

The process is pretty simple. Many years ago I made several large platters for sale, but they lacked character so they didn’t go anywhere. They promptly became an integral part of my finishing process. I sand my bowls to 600 grit. I place the bowl for finishing on the platter. I tear a 0000 pad of steel wool in half and dunk it into the finish mixture (you must wear nitrile gloves for this), then use it to apply the finish liberally to both sides of the bowl. Think of the steel wool pad as a sponge, and you are giving your bowl a sponge bath. The plan here is to keep the bowl wet with finish, so you must apply every few minutes, depending on the wood. On the first couple of applications, you will plainly see that the finish is being absorbed by the wood, so you need to reapply promptly. You don’t want any areas of the bowl to dry during the application process. What isn’t immediately absorbed will run into or off of the bowl. This is why you’re using the platter. The runoff can be picked up with the steel wool pad and reapplied. Do this for thirty (30) minutes, dunking into fresh finish as needed. After thirty minutes use (Bounty full sheet doubled) paper towels to wipe off all finish material to dry. I then place the bowl on a small circular stand made from a broken band saw blade for one hour. After one hour, repeat the process once, and you’re finished.

A couple of supplemental points. I find that anything more than the two back-to-back applications is pretty much a waste, as the wood has absorbed about all that it can take at that point. I make a lot of bowls, so I find it to be much more efficient time and material wise to wait until I have six pieces ready for finish, that way I’m constantly applying to the bowls one after the other and not having to wait for each application to absorb. Mix enough finish for both coats. You can recover what’s left in the platter from the first coat and pour it back into your container. However, anything that’s left over after the second coat should be properly disposed of. 2 – 3 ounces of mixture should be plenty for a 14” bowl, depending on species, but estimating this is a learning process and I always have an ounce or two left over. It’s nice if you can ventilate during the application process because the mineral spirits are evaporating while you apply. Be careful how you dispose of the paper towels, as they are potentially flammable/combustible. I have a cheap collapsable clothes drying rack from Target that I put just outside and hang the towels to dry before I dispose of them. Rags would not be reuseable. It’s also important to thoroughly wipe clean and dry your platter after each coat so that it’s ready for another use. I’ve been using the same six platters for years, and they have so much finish built up that they hold water over night. After completing the application process, you should be able to minimally handle the piece the next day. However, I prefer to wait 3 – 4 weeks before I put them out for sale, keeping them on the band saw blade stands, thus assuring a full cure. After that, you may find that you’ll want to give a brief once over with 0000 steel wool, and maybe not, again depending on the species. When finishing burls, live edge pieces or pieces with bark inclusions, I use an air compressor to blow excess finish out during the paper towel drying process. After full curing, there may still be some minor evidence of excess finish. This is easily buffed out with 0000 steel wool.

Supplemental Point #2. At the August 17, 2024 CW Turnout I described and showed an experiment that I tried and was pleased with the results. I had turned and finished with my standard finish mixture a redwood bowl, which absorbed the finish like a sponge but still lacked the depth that I was hoping for. After a full cure period, I wiped on a thin coat of pure tung oil, and let it stand for about ten minutes. I then wiped it dry with paper towels. This produced the depth that I was looking for and left a bit of sheen. As stated above, I’m basically a low sheen person, but I was pretty pleased with the results. I then took two finished cherry bowls that had come from the same log and had been finished the same way and fully cured. I applied the thin coat of tung oil to one of the bowls using the same process as the redwood bowl, wiping away all excess after fifteen minutes, and compared the two. Again, the pure tung oil left a slight sheen compared to the bowl without. It was just enough to give some depth to the wood, yet still retains the characteristics of the base finish mixture that I like. Low sheen / no sheen –all a matter of personal preference.

I’m here for your questions,

John Kerr

Johnkerr521@gmail.com

Response to Question:

The food safe question comes up occasionally, but I wouldn’t characterize it as an “issue” with potential customers, many of whom reminisce about the wooden bowl(s) that their mother or grandmother used for many years. As stated above, customers who have purchased a bowl from me tell me that they use it every day. Others who may be less familiar are asking a simple and legitimate question. I stress that this is a fully cured finish that is in the wood, not on it. More often, I’m asked about cleaning, and when going over the various do’s and don’ts folks understand that there needs to be some sort of finish to protect the wood. I stress for various reasons that my wooden bowls are not meant for hot foods, and I have a “care and caution” memo that I enclose with every purchase. By waiting a full 4 weeks for the finish to cure before putting it out for sale, I am confident that elements of my bowl finish will not be jumping off of the bowl and onto someone’s salad. I can honestly say that I have never encountered a potential customer who had a serious food safety issue with the finish on my bowls, but if I do in the future, I will try to interest them in a nice vase.