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Polyurethane for Guitar finish? - Martin McGrath
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Martin P. McGrath
Apr 20, 1995, 3:00:00 AM4/20/95
to
Hi-
This is my first time posting, so forgive me if I make
some naive mistakes. I was wondering about using clear
polyurethane to gloss finish a koa wood electric guitar.
When discussing finishes, most people seem to talk only
about lacquer for electric guitars. Would there be any
problem using Varathane Diamond Finish IPN polyurethane
on my koa guitar? It's supposed to provide a hard, water
resistant finish when dry. I've used it on other projects
(not instrument finishes, though) and it is very nice stuff
to work with. If there is a problem with polyurethanes, in
general, for guitars I would like to know why. I'd also be
interested in why lacquer is preferred (if that's the case).
Thanks, Martin
This is my first time posting, so forgive me if I make
some naive mistakes. I was wondering about using clear
polyurethane to gloss finish a koa wood electric guitar.
When discussing finishes, most people seem to talk only
about lacquer for electric guitars. Would there be any
problem using Varathane Diamond Finish IPN polyurethane
on my koa guitar? It's supposed to provide a hard, water
resistant finish when dry. I've used it on other projects
(not instrument finishes, though) and it is very nice stuff
to work with. If there is a problem with polyurethanes, in
general, for guitars I would like to know why. I'd also be
interested in why lacquer is preferred (if that's the case).
Thanks, Martin
*********************************************************
mpm...@ccmail.monsanto.com
--My lack of knowledge and desire to express it, is strictly
my own.-- MPM
gary watts
Apr 20, 1995, 3:00:00 AM4/20/95
to
Martin P. McGrath (MPM...@ccmail.monsanto.com) wrote:
: Hi-
: This is my first time posting, so forgive me if I make
: some naive mistakes. I was wondering about using clear
: polyurethane to gloss finish a koa wood electric guitar.
: When discussing finishes, most people seem to talk only
: about lacquer for electric guitars. Would there be any
: problem using Varathane Diamond Finish IPN polyurethane
: on my koa guitar? It's supposed to provide a hard, water
: resistant finish when dry. I've used it on other projects
: (not instrument finishes, though) and it is very nice stuff
: to work with. If there is a problem with polyurethanes, in
: general, for guitars I would like to know why. I'd also be
: interested in why lacquer is preferred (if that's the case).
: Thanks, Martin
: Hi-
: This is my first time posting, so forgive me if I make
: some naive mistakes. I was wondering about using clear
: polyurethane to gloss finish a koa wood electric guitar.
: When discussing finishes, most people seem to talk only
: about lacquer for electric guitars. Would there be any
: problem using Varathane Diamond Finish IPN polyurethane
: on my koa guitar? It's supposed to provide a hard, water
: resistant finish when dry. I've used it on other projects
: (not instrument finishes, though) and it is very nice stuff
: to work with. If there is a problem with polyurethanes, in
: general, for guitars I would like to know why. I'd also be
: interested in why lacquer is preferred (if that's the case).
: Thanks, Martin
Polyurethanes in general are much harder to buff out. Lacquer is
very forgiving as you can wet sand any problems and reshoot it.
Polyurethanes show scratches from sanding more and require more elbow grease
to get them out. I usually have to go to 2000 grit before buffing.
I use Meguiars #2 and #9 in that order with a Finesse buffing wheel.
THis takes large amounts of time to get the equivalent of the
polish of lacquer.
I haven't used the particuliar Varathane you mentioned but never had good
luck with original varathane drying hard enough to wet sand and and buff.
Gary Watts
Bill Groves
Apr 21, 1995, 3:00:00 AM4/21/95
to
Martin, you didnt mention why you are finishing (refinishing?) the
koa. Is it for protection, color, and has it ever been finished?
If not, or if its totally stripped I would oil finish it
(as does Carvin and other koa luthiers)
Koa pores fill with multiple applications of tung oil yet retain
beautiful color and is reasonably durable.
Gd. luck.....Bill
koa. Is it for protection, color, and has it ever been finished?
If not, or if its totally stripped I would oil finish it
(as does Carvin and other koa luthiers)
Koa pores fill with multiple applications of tung oil yet retain
beautiful color and is reasonably durable.
Gd. luck.....Bill
George4908
Apr 21, 1995, 3:00:00 AM4/21/95
to
I, too, have used Varathane Diamond Finish (the low gloss version) on
furniture and had good results with it -- easy to use and produced a nice
finish. But I have read postings here and elsewhere to the effect that
urethanes are not recommended for musical instruments because they tend to
deaden the vibration of wood, whereas a thin coat of nitrocellulose
lacquer allows for vibration. Even acrylic lacquers have been criticized
by some for their sound-deadening properties, compared to nitro. For
environmental reasons, many repair/refinishing shops are giving up on the
nitro, however, and going with the acrylic since it's easier and cheaper
to find, and does not bring down the wrath of the EPA. I'm just learning
about this stuff, so take anything I say with a grain of salt!
furniture and had good results with it -- easy to use and produced a nice
finish. But I have read postings here and elsewhere to the effect that
urethanes are not recommended for musical instruments because they tend to
deaden the vibration of wood, whereas a thin coat of nitrocellulose
lacquer allows for vibration. Even acrylic lacquers have been criticized
by some for their sound-deadening properties, compared to nitro. For
environmental reasons, many repair/refinishing shops are giving up on the
nitro, however, and going with the acrylic since it's easier and cheaper
to find, and does not bring down the wrath of the EPA. I'm just learning
about this stuff, so take anything I say with a grain of salt!
Martin P. McGrath
Apr 24, 1995, 3:00:00 AM4/24/95
to
finish because I would like to do those things myself (I'm very
fond of a particular pickup configuration and Carvin had a sale on
unfinished neck thru guitar bodies, so I went for it.) I intend
to tung oil the back of the neck but I think the koa looks great
with a nice clear high gloss finish, then I'll mount the hardware
and my favorite pickups. That's the plan at least. I have worked
wiht tung, and that would be a very fast way to get the guitar
finished but I have my heart set on high gloss for the body. If you
have any moregood suggestions or tips, I'd be interested.
Thanks....Martin
Jeff P. Vogelgesang
Apr 27, 1995, 3:00:00 AM4/27/95
to
I'm not a professional luthier, but I have perimented with
various finishes on acoustic instrumen (a guy in Columbus Ohio,
Ray Sparks builds mandolins and guitars, and I, being efty,
have bought several unfinished). I have had very good results
from high grade automotive laqIer--its harder and I detect no
appreciable tone differences between those and my Martin D-18,
other than the fact the D 18 is 45 years old.
The best luck I've hadwas with a mandolin that I french
polished-- using a tampon to apply freshly mixed shellac by
hand. The instrument sounds good because the method allows you
to fill the grain and get a decent finish with very little
material buildup--the finish is really only one coat thick due
to the application, which involves pumic and essentially
buffing and policshing as you are adding material. Good luck.
various finishes on acoustic instrumen (a guy in Columbus Ohio,
Ray Sparks builds mandolins and guitars, and I, being efty,
have bought several unfinished). I have had very good results
from high grade automotive laqIer--its harder and I detect no
appreciable tone differences between those and my Martin D-18,
other than the fact the D 18 is 45 years old.
The best luck I've hadwas with a mandolin that I french
polished-- using a tampon to apply freshly mixed shellac by
hand. The instrument sounds good because the method allows you
to fill the grain and get a decent finish with very little
material buildup--the finish is really only one coat thick due
to the application, which involves pumic and essentially
buffing and policshing as you are adding material. Good luck.
Dsp3
May 4, 1995, 3:00:00 AM5/4/95
to
There are several new water based finishes for guitars; Crystalac,
Hydrocoat, and the one you have talked about. I know that there are
manufacturers using these, although they discuss the need to experiment on
scrap wood prior to hitting your project. Your wood choice (koa ) may
provide some surprises, but I'd say give it a go. One can always sand off
the choices that don't work.
Hydrocoat, and the one you have talked about. I know that there are
manufacturers using these, although they discuss the need to experiment on
scrap wood prior to hitting your project. Your wood choice (koa ) may
provide some surprises, but I'd say give it a go. One can always sand off
the choices that don't work.
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