You don't have to spend boatloads of cash to get adequate tools
for the job, as long as you focus on a few details.
Guns
Chain stores like Harbor Freight, Grizzly, Home Depot and
others all have rather inexpensive gravity-fed guns for an
average price of about $50 to $75, and any of these guns will do
the job. In a gravity-fed gun, the cup is above the gun and the
paint is fed by gravity. A cup gun has the paint cup hanging
below, so that the paint is fed by a siphon. You'll need a benchmount
gun hanger for your mixing table, which will cost $10 to
$20, as well as a gun hanger for the spray booth so that you can
work with greater convenience and efficiency. I use quart guns
for clear coats or when spraying any solid color or large amount
of transparent color, like on the back of an instrument. Detail
pint guns work great for ‘bursts and headstocks. However, you
should never use a clear or color gun for metallic paints, nor
should you ever put metallic paint or guns in your gun washer.
Do that, and you can kiss your nice ‘bursts and solid colors
goodbye. Like the song says, "You gotta keep ‘em separated."
Filtration
The main thing in the process is to keep your air supply clean. I
really think this is the most important detail, so I use a threestage
filter with a micron air filter for debris removal, along with
a coalescer filter for removal of oils and a desiccant dryer to
remove water.
Doing the Dishes
A couple of five-gallon buckets, four gallons of acetone or gunwashing
solvent, some safety glasses and a pair of rubber gloves
gets you doing your dishes and washing your spray guns. Keep
one bucket for your main dirty washing and a second for a
cleaner final rinse. And be sure to have one last bucket for waste
catalyz.ed materials, which become disposable as trash once
they’ve hardened. You can also find paint gun washers. Yes, I
said a dishwasher for paint guns. It’ll cost around $400 or $500
new, but it’s a small price to pay for something that makes life
so much easier. If you’re using urethanes, it’s important to
disassemble your guns each night once the day’s spraying work
is done.
Air Pressure and Enviroment
The type of paint material you’re spraying will play a role in
your paint environment. Lacquers dry pretty quickly, so it’s less
likely that airborne debris will get stuck in your paintjob.
Urethanes, however, stay wet about twice as long, so obviously
anything you can do to keep the dust to a minimum will be
beneficial. Ventilation is a key to getting vapors out, but it can
also give rise to airborne debris. Using a wetting agent on the
floor (such as water with a bit of dish soap added) keeps the
floor wet longer than plain water can. Or, you can use black
roofing paper. It’s very sticky and acts like flypaper to prevent
dust liftoff.
Air Pressure
You will need to adjust your air pressure based on the feel of
your gun and the material viscosity you're spraying. I use 40 lbs.
as a rule of thumb and adjust the pressure up or down after
shooting a few test patterns on a scrap board. The satin material
is thicker, so you might find you’re turning up the pressure a bit.
You might also find yourself spraying at pressures as low as 20
lbs. or as high as 60 lbs., depending on which setting suits the
job. Lower settings put more paint on the guitar and less into the
air.
Degreasing
Now that the guitar is nicely sealed, you’ll want to degrease the
guitar before any additional coats are applied. This will keep
those greasy burrito-smeared hands from creating "fisheyes":
those craters in the finish where your paint has run away from
the oil. For this we use the R2 reducer and a paper towel, but if
possible you should use lint-free towels. You’ll find them at your
auto-body supply store. Mask off any binding at this point using
1/4" wide, green fine-line tape. You’ll also find that at your local
body shop or at www.mcmaster.com.
Color
The colors we’re using here are known as candy colors, in
reference to transparent colors of the kind usually sprayed over
metallic base coats in the auto world. (This tutorial skips the
discussion of metallic base coats for brevity’s sake.) When it
comes to ‘bursts, I find that the center color comes out best when
it’s sprayed last. If possible have all your burst colors in separate
guns so that you can spray them back to back and then touch up
as needed by having all the required colors available.
When spraying a cherry sunburst I’ll spray the back of the guitar
"trans red" first, and then I’ll flip it over and spray the burst. The
burst pattern will either be a "pear burst," which is in the shape
of a teardrop, or a "perimeter burst," which hugs the body
perimeter. Often you’ll see a three-tone burst where the dark
outer color is sprayed in a perimeter burst and the second
blending color is sprayed as a pear burst and the third center
color is sprayed last. Prior to spraying the front burst, though, be
sure to inspect the face of the guitar for any overspray you might
have generated. If there is any, wipe down the face with R2
again. Don’t let anything drip around to the back of the
instrument.
Any questions or comments visit www.finetunedinstruments.com
www.meangene.org
or email me at info311@verizon.net
Fine Tuned Instruments LLC, home of b3 instruments.
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