Farmhouse Tabletop Finish
Finishers evaluate options for furniture coatings. November 27, 2007
Question
I'm looking for some advice on finishes for a walnut farmhouse table (character grade, with knots, 8/4 leaves, 8"+ widths or better), but more specifically the tabletop. The table will have daily use in the kitchen. The client's preference is for something that does not look like a coating - not a "bar-top" finish. This will be an antiqued piece - fatigue sanded, and distressed. So ideally a brush-applied finish will probably look more period style.
I was considering Waterlox tung oil varnish as a first choice (brush applied all coats). However, I am looking for some other options. I'm curious what success others have had with solvent based conversion varnish (at one end of the spectrum) or water based urethane (at the other end). Granted, both the solvent and water based finishes are typically spray applied... Has anyone had luck with a water-based urethane that can be brush applied?
Functionally, I think the greatest concerns are water rings, and the ability for the homeowner to do repair work. That is one of the reasons I was considering Waterlox - brush applied and can be easily touched up by the homeowner.
Also, are there any special finish concerns when dealing with character grade walnut that's 8/4? Should I use 4/4 stock instead?
Forum Responses
(Finishing Forum)
From contributor R:
I don't think that tung oil really gets the kudos that it deserves. Yes, you can find pure tung oil online at a few different outlets - just let your fingers do the clicking. Many Chinese artifacts brought up from the deep were finished in tung oil and are as pristine today as the day they were finished. The key to a beautiful tung oil finish is patience, time, and more time. If you have those luxuries at your disposal, you have the makings of a beautiful, long lasting finish that, when need be, can be touched up by anyone with a double digit IQ.
From contributor P:
I just did a similar walnut table and did two samples for the customer - one lacquer and one 2K PU. Both looked equally good, but the durability of the poly was the selling point. By applying a single thinned coat of sealer and a single coat of poly in a matte sheen, the finish looked tight to the wood and the grain showed beautifully. The low sheen added to the effect by keeping the emphasis on the wood and not the shine. If brush marks are important to the look your customer wants, then the oil base varnish (Waterlox) over a single coat of orange shellac would be the schedule I'd choose. Like you say, it's a durable finish and can be recoated/renewed in the future by someone without a lot of experience using a padding/wipe-on technique.
From the original questioner:
Thank you for the responses. I will go ahead with two sample boards. I will try a spray applied water based urethane (dead flat) over a sealer, then rubbed out to look a little less new. I will also try the Waterlox. However, I have a question about the orange shellac. Does this provide a better bonding agent (aka primer) to ensure greater adhesion?
From contributor B:
Contributor P, whose 2k poly has a matte sheen? And the sealer, was it the same system sealer?
From contributor P:
The shellac is just for the warming effect it has on the color of the wood. It also provides a look of depth to the finish. It's even more beneficial to the look when you use water-base topcoats, but the shellac needs to be dewaxed to avoid adhesion problems with the WB.
I'm using Milesi PU from Chemcraft. The sealer is versatile and can be thinned to make a dependable washcoat for staining or glazing and sands very nicely.
From contributor T:
My own is rustic mahogany (used 8 foot skids from a shipping container). Bought legs from Adams Wood Products. I finished it in Valspar CV, 15% dull. It's two years old, I've got two kids, served a couple of hundred meals, and it looks great still. Although if they abused it - someone would be in time out (they know). If it is a family, go for the durability of a CV. Give it a few years - it will get the look they eventually want. If it is just two adults, go with the Waterlox. This will give you the protection and you can control the look, if you have not done a lot of CV before.
From contributor P:
I'm interested in any testing data you have access to that leads you to believe CV is more durable than an oil-base varnish. I understand the catalyst makes CV cure faster than an oil-base finish, but haven't seen any data that compares the durability properties of CV vs. oil-base varnish. Do you have a source of info on this?
From contributor T:
By testing data, do you mean other than the 25 years of doing this? I have an old copy of AWI finishing standards - you could start there. In those 25 years, I have used oil varnish, oil polyurethanes, nitro lacquers, CAB acrylic lacquers, pre-cats, water-based, and now mainly Valspar CV (100+ gallons this year). Once cured, the stuff is almost bulletproof.
From contributor P:
I was just wondering if you had some reason to believe CV is tougher than oil-base varnish. I know CV is a durable finish and have used plenty of it as well. The same is true for oil-base varnish. For some years I've been curious how oil-base varnish, including polyurethane, would compare with CV in side-by-side testing. So far, I haven't found any testing data that compares the two.
I started with hand applied finishes back in 1973 and have progressed through the entire spectrum of finishes and equipment over the years. Based on my experience, I'd have a hard time judging whether CV is tougher than oil-base varnish or not. Both stand up to some very hard use. The benefit of CV is the fact that it's a spray finish and cures quickly.
The AWI chart covers/compares spray finishes only; oil-base varnish isn't included. Some data on the old chart is out of date (e.g., WB ratings, toxicity and clarity values), but overall it provides a decent comparison of the spray finishes.
On the chart, CV defines the TR-4 category. If oil-base varnishes were included, I think it would have to rank as a TR-4 based on the finishes covered and their relative ratings. Once cured, oil-base varnish has excellent durability properties that mirror the ratings listed for CV. It does take longer to cure, though.
