Some thoughts on finishing
Posted: Sat Aug 17, 2013 10:20 am
"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?
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?