Some thoughts on finishing

[John Link]

"Anyone can say anything - and they will"

How true. Having said that ...

I sprayed lacquer for a living for 13 years while in high school and college. It makes a stunning finish and eventually the spray gun becomes an extension of your hand - a very efficient, flowing extension that produces amazing results with minimal effort.

But how nitro ever became the "standard" for guitars is beyond me, unless it offered some benefit to the bottom line no other finish could provide. Every instrument I finished with it, whether new or a significant repair, took two years to recover sound wise. The stuff shrinks something awful (a virtue too, see below), so much so that pores must be filled full flush with something that does not shrink at all (epoxy?) or they will show up when the lacquer finally dries. As it ages, you must expect crazing and cracking. Even the most flexible formulations do this.

But worst of all is its lack of safety. When I was a high school nut, and long before the glue sniffing craze, I would settle into a closet, take off the mask (which was not very good anyway), and just point the gun at the ceiling and breathe it in until I was fully looped. Not that I was completely straight in the first place because "ventilation" wasn't the concern it is today. Spraying that stuff and its solvents is suicidal unless your equipment reduces your exposure to absolute zero. Even though I was strong and healthy, I felt like crud for several hours after the buzz wore off.

Then there is flammability. Once atomized, even with modern HPLV equipment, it just begs to ignite. When it does, it explodes. So you need to do it outdoors or have expensive explosion proof ventilation systems in place, both for spraying and the initial dry cycle.

It does rub out beautifully. For the fanatic, you can forgo the buffing wheel and do it all with finer and finer sand paper. I have used 12,000 grit which feels like suede, not sandpaper, for the final rubout with soapy water. Looks great. Takes me about 40 hours to get there. And for all my negativity, I must admit that I like how, after about 2-4 years, the shrinking of the thin application reveals the grain structure topology of the top without giving up any of its gloss. The pores in the back and sides, I never have learned to like. In the end, all that shrinking is a good thing. You must put enough on to get a wet coat that flows and unites with the finish underneath if you want it to look fabulous. Thanks to the shrink, you don't have to pay the price of a heavy finish to achieve that look.

For anyone willing to devote 40 hours to finishing an instrument, French Polish is a great alternative. It too shrinks, but starts from an even thinner base, so there is less of it. And it dries faster, so its damping effect expires much sooner. It is easy to repair and repairs seem to have less of a negative affect on sonic properties. Supposedly it is delicate, but guitars are delicate as a whole and should be treated so. Besides, some tests have been conducted that show it is much less affected by water that is commonly thought. Looks just as good or better than lacquer. Virtually non toxic. Equipment to apply is cheaper than dirt. Good upper body exercise. What's there not to like?

[Dave Sayers]

I must confess that I was quite put off by some of the chemicals in nitro cellulose, and having enough problems with other things decided I'd best not add to them with chemical inhalation. As a result I've been using and trying all sorts of finish. At the moment I'm using Minwax high gloss tung oil to finish a figured maple body (Picture attached). I can use this indoors. I wanted something that would allow the figure to shine through. I don't fill my guitar bodies. If they don't look like gloss polyurethane UV cured, good.
I've also used Tru oil sealer and filler, although I don't like the final colour of the tru oil final finish. French polish is ok.
Necks usually get a smoothing and then a coat of renaissance wax, which makes them feel very smooth and play very nicely. It doesn't show finger prints.

[Dave Bagwill]

That wood looks yummy!

[mike-p]

I've heard about spraying french polish, sounds ideal to me, anyone done it?

[ken cierp]

Yep -- any chemical that protects the wood is just fine. Some premier classical makers use varnish, many use varnish or lacquer on back and sides French Polish on the sound-board, a convension that top notch classical players demand. Saxsauer uses varnish on all his gutars $$$$. Kinkead uses Tru-oil, I am with George Lowden on satin finish -- but many really like the high gloss so their instruments can be compared to Martin, who in my opinion has perfected the nitro process -- simply hard to beat.

Yes you can spray shellac and rub it out -- that however is not a FP finish which is meant to be microscopically thin.

[mike-p]

I do like the finish on lowden guitars, do you know what process they use?

[Lonnie B]

I've used Tru oil on a few guitars and mandolins. But here lately after touching up old Nitro finishes a few coats of Tru-oil on some re- builds. I have to say they look very good. The old finish shines through the Tru oil very nicely. However I'm a fan of FP. My lungs cannot stand any nitro spray finishes. So it's hand rubbing for me.