REQ: Info on Spray Painting Guitars
Don Gauthier
on spray finishing tools. In particular, do you recommend an oil (or
oiless) air compressor or an HVLP system? What is a good spray gun to use?
Thx for the ideas,
Don
email do...@bnr.ca
Curtis Novak
>I'm starting to build guitars as a hobby. I'm looking for some advice
>on spray finishing tools. In particular, do you recommend an oil (or
>oiless) air compressor or an HVLP system? What is a good spray gun to use?
Tips for Color Finishing Guitars and Bases
If the guitar is has a removable neck, it is a good idea make a mock
neck to be used as a handel for painting and hanging. To make this handle
you will need about a 2 foot piece of wood or steel cut to fit in the neck
cavity on the body. Make the end of the handle that will bolt to the body
smaller than the neck cavity. This will allow the paint to get in the neck
cavity too. Drill the holes in the handle that are needed to bolt the
handel to the body then drill another hole on the other end of the handel
to be used for hanging the body during the drying periods and/or during
painting. The handel I use is a 1x2 that uses 2 screws. I alternate these
2 screws all holes on the body get painted. It is also a good idea to
place some kind of spacers between the body and the wood handle, I use
large nuts, this allows paint to get underneath handle. I usually hang it
for drying in an unused closet so not to be disturbed.
WOOD PREP
In refinishing an instrument if at all possible I do not remove the
base finish, because you can sometimes pull your hair out trying to seal
the wood without the grain rising. I once refinished a bass for a music
store this poor thing was left in the direct sun in a van during a trade
fair well the heat melted the finish bad. It looked real bad but was an
easy fix all I had to do was test the paint type, sand it down smooth and
spray the same color over it, clear coat it, shine it and that was it no
wood prep.
Patching holes are some what harder. I have a Jaguar I am working on
that has a bullet hole through the body (Must have been a rough night uh?)
well I used a synthetic Bondo this time, but I have not yet gotten the
patch to stop rising with moisture. Synthetic Bondo is more stable however
water base wood dough for large holes.
There are 2 ways to fix small dents and dings. On some dents it is
possible to swell them out by putting a wet rag on the dent and then
palceing a hot soldering iron on the wet rag over the dent. The steam
causes the crushed wood fibers to expand back out this process is good on
clear finishes and dents in the neck. I once had to refinish a beautiful
Strat that a puppy had chewed up. There were zillions of little dents in
it. I just used wood dough on these and when it was finished you couldn't
find a single hole.
WATER SANDING
You will need a bowl of water, water sandpaper, clean soft rag or a towel.
Get a bowl of water place sand paper in the water for a minute or so. Then
take the paper and lightly in a circular motion start sanding. Some
suggest to use a sanding block to keep from sanding uneven, but I find that
the block tends to build up too much debris and scratch the finish. I use
a sanding block during wood prep, and use a flat hand on water sanding.
Frequently wipe the body with the rag and rinse the paper in the water to
clean the paper. The water will help to lube the sanding process so you
need to keep rinsing the paper to keep the paper free from debris. You
will also want to keep wiping the body with the rag to keep the body from
soaking up too much water causing the body to swell. This swelling usually
happens where the raw wood is exposed like the screw holes or where you
have sanded through. Try to keep these places as dry as possible.
PAINTS
When painting always paint the sides, and the horns first then paint the
front and back this minimizes any overspray on the front and back. Use
smooth complete sweeping strokes. It is also recommended that you use a
continuous stream of paint not stopping and starting at each end. This is
recommended because the sprayer will spit any paint blobs that may be on
the tip, or when pressure is not at its peak. I would also recommend that
for your first time you start with a light color. A Darker color will show
every mistake including minor things like swirls from in inadequate sanding
and dents or blemishes that you will not see until you are done.
I prefer Lacquer based paints because most of my jobs have been to
refinish vintage instruments. Fender use to use actual Auto paint for
there guitars for example Lake Placid Blue is actually a 1957 Cadillac
color. Lacquer finishes are much more brittle than polys that is why those
old Fenders chip so easy. Lacquer will also offer a much higher gloss than
polys. It is your pick on which to use, but it is VERY IMPORTANT TO NOT
MIX THEM!!! If you do mix them for example by using a lacquer primer,
lacquer color coat, and a poly clear coat you will have just created a
paint remover, and you will have to start from scratch. Always test the
paint on a scrap to make they are compatible.
Primer Sealer
I usually use BIN as a primer you can found it in the hardware store.
It is used for covering graffiti, crayon and is compatible with lacquers,
polys and most other paints, but remember always test. A big part of
refinishing is trial and error.
Color Coat
For the color coat I use Dupont acrylic lacquer if your lucky as I was
the paint store has the original paint chip books from the 40', 50's and so
on so you can search for that perfect color.
Clear Coat
Some people don't use clear coats, but I prefer them because it gives a
much higher gloss, deeper finish, and it also protects the finish. I break
a rule here in mixing brands but I prefer Shurwin Williams #### sealer from
your auto paint store. It is real simple just thin and spray.
Paint Sprayers
You can purchase what is called a Jet Pack which is an presure
cartridge that attaches to a jar holding your paint. These sprayers give
good coverage and you can get refill cartridges, and use this as your main
sprayer. You can also find high quality color, and clear paints in factory
packed spray cans. Before you buy a can of spray check the always tip. It
is best if the tip is an adjustable pattern tip not just the standard pin
hole tip.
Steps to follow for Color Finishes.
1 Sand and fill the raw wood use 320 grit. If the grain is rough sand smooth
wipe the body with a wet rag let the grain rise when dry sand smooth again.
Repeat this until the grain dose not rise any more. Let it set for a day
or so to let the moisture evaporate.
2 Spray light coat of sealer let dry let set for 1 hour repeat with 2 more
coats. Let it set for a day.
3 Lightly water sand finish smooth 320 to 400 grit paper. (see water sanding)
4 At this point fill any dings and scratches that show through from sanding
you will want a smooth finish. For a filler you can use Bondo in the
squeeze tube. Let set for a day to allow moisture to evaporate.
5 Repeat steps 3 through 5 until finish is smooth. Let set a day or 2.
6 Spray a light coat of your color coat let set until the coat flashes (dry
to the touch) then spray a little heavier coat let it flash again repeat
this 2 more times then spray one final coat and let set about 3 days.
7 At this point I water sand with 400 grit to smooth out finish, and for one
last check for dings.
8 If you sanded through the color or found any mistakes fix them wait a day
then repeat steps 6 through 8 until satisfied.
9 Wait 3 days or so then spray your clear coat start with a very light coat
let it flash then spray a little heavier coat again let it flash repeat
this 3 more times then do one kind of heavy coat to give a nice top coat be
careful not to do it so heavy that it will run.
10 If runs or other problems sand out problems and try another layer or so of
the clear coat.
11 Give it a rest for a week or more to let the finish set.
12 Now the magic starts. Start water sanding with 400 grit until the whole
body is smooth. Switch to 600 grit do same at this point it should have a
finish like stainless steel next I go to 1000 grit, then 1200, then 1500,
then 2000. at this point it should look like a sheet glass with very fine
scratches.
13 Now you are ready to rub-out the finish. I use Meguiar's #4 (found in auto
paint stores)it is a gritty compound that takes out more of the scratches.
I ball up a soft rag and squeeze some compound on the body and rub like
hell in a circular pattern (think of Karate Kid. . .wax on wax off). Push
hard the friction helps to melt and smooth the finish. I would not
recommend using a power buffer at this point unless you are really
experienced cause it is easy to melt through the finish and depending on
how bad you melt it you will have to go back to step 3 or 6.
14 Final step use Meguiar's #7 and once again rub like hell.
15 Give it a day before you assemble it, and pat your self on the back for a
job well done.
If you have any comments, suggestions, questions, corrections please feel
free to let me know. I would also be interested in any thing you have learned
on you project, and I would love to see any before and after pictures.
Good Luck. . . be patient
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| 0 0)
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| ,___ - Later Dude
| / Curt
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. . . Just say NO to coyote art!
Curtis Novak
cu...@lanl.gov
Sonam
>
>I'm starting to build guitars as a hobby. I'm looking for some advice
>on spray finishing tools. In particular, do you recommend an oil (or
>oiless) air compressor or an HVLP system? What is a good spray gun to
use?
>
If you don't have a compressor now, look into Fuji HVLP
systems - if i were going to buy one, that's the one I'd buy.I use high
pressure compressed air to shoot both nitrocellulose and auto spray
finishes, and while i have a Binks "door jamb" gun, my favorite tool is
Iawata HP-BC2 airbrush ($250), closely followe by a Paasch VL airbrush
($100). I find that an airbrush gives a much better control and finish, and
allows me to do some of the strange finishes that I've been asked to do.
My wife hates the fumes however, and a real spray booth is
about $2000 to build, so i am looking into water-based finishes now
(there's a thread on this in rec.woodworking), but I've yet to see one that
looks like nitrocelulose. And for solid body guitars, nothing beats the
selection of auto paint available, so I just may put the money into a "real'
spray booth.
Anyway, always buy the best name-brand equipment, stay away
from Taiwan stuff, and perhaps get Dan Erlewine's video if you dont yet
have it.
Hope this helped, and if you have any more questions, email
me.
--
Peace,
Sonam
Custom-made solidbody guitars - acoustic and electric repairs