Wednesday, July 13, 2016

About the Oil

I get asked a lot about the oil that I use, and over the years I've used many different types. One mix that I've often returned to is a spar varnish, raw tung (or linseed) and mineral spirit mix. The next question that I get asked is usually about the proportions, which is perfectly natural.
But the answer that I feel compelled to offer isn't as easy as a the question. I think that it's more important to understand that each of these three components play a role and depending on where I am in the finishing process or the environment that I'm working in, I might change it up a bit.
First, the spar varnish. This is the tough flexible finish that dries to form the shine and water resistance. But, left alone, it is way to sticky, thick and fast drying. So to slow it down to the point that I can lay on a thin layer, I add the raw oil, which goes on smoothly but if applied alone would take way to long for my patience to build and dry. But mixing these two together gives a mix that is akin to the thickness of honey, so I add mineral spirits to make it flow. If it's the first coat and my goal is to flood the oil on and have it soak in, then a generous amount of mineral spirits is a good idea, but for later coats that I pad on and wipe off the surface quickly, then a thicker mix works fine. Often, I'll burnish the chair before the final coat and use more raw oil in the last mix to get a "softer" look. I don't wax my chairs because I've seen trouble with body heat causing clouding, but maybe I just don't know how to use it or have used the wrong stuff.

So as far as I'm concerned, there is no magic mix. I suppose that the simple way to put it is that whatever you do, you are gonna end up with a basic finish made up of cured oil, and using the different elements is simply an opportunity to guide the process. I usually start with leaning towards too much spar and fill in the other elements to get the consistency and time that the project and weather call for. I always check my rag to see how long it takes to harden, if it isn't hard after a night of drying, add more spar.

And of course, dispose of rags in a safe way to prevent spontaneous combustion!!!

4 comments:

Institution Furniture said...

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Anonymous said...

Great look-in the pics above are you adding a tint, or is this just the color from spar varnish and tung oil?

Peter Galbert said...

this chair was fumed in ammonia which darkens the piece substantially when oiling. The oil will add a slightly warmer color over time

Silver Tips said...

nice design of chairs.. keep posting

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