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I'm lazy, but not lazy enough to pray and spray. I'm sure this is one of the many questions asked, but what should I finish my guitar with? I have used Tung oil to polish out the necks of all my guitars (electric and acoustic). I just buff the oil in with light sandpaper and steel wool. I have heard true oil is also comparable. Are oil finishes one of the better options for tonal concerns? (The wood is mahogany with a spruce top). If so, how is the best way to apply the oil finish?

Thanks,
Sam

100% pure tung oil produces a flat almost velvet-like surface. Tru-oil produces a shiny high-gloss surface. Are you talking about pure tung oil, or a "tung oil finish" of which tung oil is only a component?

Just pure Tung oil.

I don't know enough about either one to offer much of an answer. I can tell you that Carter, the luthier who is mentoring me, doesn't like oil finishes in general. I'm not sure that is based on any solid evidence, however. I think it may be his own subjective opinion. Now, he has considerable experience and I pay attention to his opinions, but in this case I'm not as "sold' on his point of view as I might be on other topics. A lot of people have used Tru-Oil on guitars and been very satisfied with the results. Still, an oil finish does add mass to to the wood and that is generally considered undesirable. Whether it is significantly different than the amount of mass added by a spray lacquer finish...I have no idea. Tru-Oil does produce a nice gloss finish. The finish you're going to get with pure tung oil won't be comparable. From an appearance standpoint, I think Tru-Oil wins hands down.

Well, I think you are right. I have done a little research myself. This finishing thing is another world in of itself. Tung oil may not be the best. I may be thinking more of a varnish of some sort now.

Probably as important as the question of what varnish is used is how it is applied. A heavy elastic spar varnish would probably not serve your interests. A lighter drying oil with resins is probably a better choice. Researchers have analyzed Stradivarius violins/'cellos for the varnish composition. It appears that a drying oil coat to seal the wood was first used, then a oil/resin mixture with iron oxides/cochineal/vermilion for a touch of color next. Few people would quibble about the sound or looks of instruments so finished. In the 1980's there were several luthiers cooking their own varnish collecting resins right off of trees. That was apparently sometimes rewarding and sometimes hazardous for obvious reasons. Much of that work has been published by FoMRHI in UK (Fellowship of Makers Researchers of Historical Instruments, http://www.fomrhi.org/). Personally, I wouldn't avoid trying pure tung oil or adulterated tung oil, I would just keep the coating thin, but enough to protect and I wouldn't expect it to look like nitro lacquer nor like french polish.

Okay got it. Will check it out.

pad on shellac. Great tonal quality, easy to do.

I don't know if it's the shellac finish, but my guitar sounds incredibly good.

I may have a natural talent for making things difficult; I had a lot of trouble getting a really good, smooth, gloss shellac finish. In retrospect, I think my main problem may have been that I tried to hurry the process and didn't allow enough drying time between coats.