From the farrier’s kit to the workbench: Making your own varnish
I fully subscribe to the notion that it’s better to make many of your own finishing “concoctions” rather than buy commercially available ones. Why, you might ask? I don’t know. Hey, why do people grow tomatoes in their backyard? Why do some smokers roll their own. Why do people make their own beer? I guess it’s just the idea that if you’re closer to the manufacturing process, the better the product’s going to be, or something like that. But I can tell you that I am surrounded by cans and jars of ingredients that have been used for many an experiment over the years. Some were successful. Some were not. But, all were expensive. False economy? No! Simply the cost of on-going education. And, what the heck, it’s fun!
I don’t use a lot of oil varnishes. It just takes an awful long time for them to dry. Plus, you have to apply them in a relatively “dust-free” environment (which my shop is not). I do use BLO (sometimes mixed with solvent turpentine). Essentially, this mixture is a very long oil varnish. Over the ages, different resins have been added to the mix to create spar varnishes of varying “flex” levels. One such resin is “pitch” or “pine tar”. This is typically a by-product from the refining of solvent turpentine and is often referred to as an item of “Naval Stores” (maintenance). But it has been used for centuries as a protective coating for homes, boats, reindeer sleds and horses hooves, not to mentions wooden planes and tool handles of all sorts. It is a dark, red, sticky product that , many times, is heated to expedite drying. So I thought, this is interesting. I wondered how it would work as a furniture finish. I’ll try it on something. So I had to find some pine tar. That didn’t take long. Seems that there are a number of pine tars available, but i had to travel no farther than Tractor Supply to find the subject of my quest.
I was intrigued. As soon as I got home, I sat down at the computer to find out just what this product was all about. Apparently, it’s most common use in the United States, is as an antiseptic applied when horses’ hooves are being maintained (and/or shod). But, I found that it is the main ingredient of a traditional artist’s varnish still used by many museum conservators. True Venice Turpentine is the resin produced by the European Larch tree. It is available from art supply manufacturers, like Winsor-Newton and, it is expensive. The Bickmore product is now called “Artificial Venice Turpentine”. Though I understand the formulation remains the same. It is very clear and the consistency of honey. An oleoresin, fatty acid, something. Hey! I’m not a chemist! I’m just “playing Mr. Wizard in the garage”. (A Caveat: Bickmore does not indicate in any of its literature, that their products were ever intended to be used as an ingredient in wood finishes. So you’re flyin’ solo here. If your project gets screwed up, it’s not their fault.)
After a little more reading, it seems that, many years ago (19th century) enterprising Americans began using sap (resin) from various conifer trees to produce a less expensive varnish. Apparently, there were several downsides to the product. Drying time, of course was an issue. But, the rosin based varnish was very bright (glossy) and soft, which was somewhat undesirable for a “fine finish”.
I decided to consult an expert for an opinion. I asked Jack Plane if he could shed a little light on the subject. Now, Jack probably knows more about traditional finishing that anyone else around. So, I was a little disappointed when he assured me that Venice Turpentine could be used only to produce a very long oil varnish. So there it was, marginal spar varnish, at best. Very expensive, marginal spar varnish. But let it be known, that I’ve never been one to be dissuaded by experience and/or logic. “Flights of Fancy” are just about as close to long distance travel as I get, these days. I just had to see what kind of result I could get by mixing some of this stuff together with some other stuff. The die was cast. The Genie, out of the bottle.
So I took two parts of Artificial Venice Turpentine, one part BLO, one part solvent turpentine then added one part Japan Drier (about 20% of the total volume). I found a suitable piece of wood, then began the process. The application needs to be in very thin coats. Twenty to thirty minutes after the sample was coated, it was buffed with a dry cloth, making sure that all liquid had been removed from the surface and that the surface had been, effectively, burnished . I waited twenty-four hours before applying subsequent coats. After four coats, the surface developed a rich, subtle glow, not as stark as the gloss level associated with straight BLO. The surface had a “waxy” feel, that probably indicates the drying time between coats should be extended, and coating thickness be kept at an absolute minimum (one of the downsides with “cross linking” varnishes). Okay, so it seems that I have a “difficult to apply product”, that requires an inordinate amount of time to dry. But, leaves a deep finish that enhances the look of the sample stock (curly maple) with a subtle sheen that does not distract. I’m not sure about the protection that this stuff will provide. We’ll just have to see how it looks several years down the road. Where’s the problem? There isn’t any that I can see. Well okay, I could have purchased a product like Tried and True Varnish Oil (my guess is that it’s virtually the same as my concoction). But where would the fun be in that? And what would I have learned? I mean, it’s all about the learning, right….?
For further reading about making you own varnishes from things that grow right outside your door. Check out Roald Remaelmo’s post on the making and use of pine tar (tjaere) from May 10th at skottbenk.wordpress.com. It’s an extensive article with lots of photos and a video and well worth the read. The photo below is Roald “burning in” the tar on a reindeer sled.
I shouldn’t have sold my blow-torch! Darn it! Think of the finishing possibilities… Darn, darn, double darn!