Sunday, June 30, 2013

Oil and varnish mix

by Brandon
A couple of coats of the oil-varnish mixture reveals the grain and figure on the African mahogany.
A friend of mine was reading this blog and asked me how I made my oil-varnish mix. The oil-varnish mixture I use is one part linseed oil, one part spar varnish and one part mineral spirits. You can substitute turpentine for the mineral spirits, but it has a stronger smell. You can also substitute tung oil for linseed oil. The advantage to tung oil is that it doesn't darken the wood as much as linseed oil. Most of the time I'm trying for a dark look to the wood so I usually don't use tung oil. Boiled linseed oil is not as expensive as tung oil. Cheap spar varnish seems to work as well as the expensive stuff.

I put the oil on thick with a rag or a small chunk of synthetic steel wool (the gray color is my favorite) and let it soak into the wood for 20 minutes to an hour and then I buff off any that hasn't soaked in with a lint-free rag, usually an old towel or t-shirt. It takes five to seven coats to get a good sheen on the wood. You should let it dry 24 hours between coats.
 
The advantages are:
  • it's easy to apply;
  • you can do it in a dusty shop or boat;
  • it feeds the wood;
  • it makes the grain and wood figure pop;
  • when you touch it you feel smooth wood, not plastic finish,
  • and it very easy to repair.

I often do a few coats of the oil-varnish mixture and then a couple coats of spar varnish. It makes a great base coat for varnish (shellac too). I think it seals the wood so water doesn't get under the varnish as easy.

When the finish gets a little dull or looks worn or scratched I just get out my little bottle of oil-varnish mix and a small hunk of gray synthetic steel wool and in no time it looks great again. This even works well when I've put a couple of coats of spar varnish over the oil-varnish mixture.

One more variation that I've heard about is adding about 10 percent of pine tar or Stockholm tar to the mixture. I'd never use this inside, but I sure would outside on a boat where you want a workboat finish. I'd do it just because Stockholm tar smells so good. My guess is that adding the tar would greatly slow down the drying time. It may stay tacky for a long time.