ReRanch
101
Equipment
Spot Repair
Area Repair
Stripping
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Introduction
Before beginning any project
one should ask if the restoration will affect the instrument in a negative
manner....
Does it well serve the instrument, the previous owners and all the owners to
come? A finish worn by years of work cannot be duplicated only replicated.
With that said, there are instruments that beg for restoration. The ones
most needy are the instruments that are one step from the parts bin. Most
of these were ruined by well meaning but inept restorers. These instruments
will most likely need a total strip and refinish. Others that will need
attention are guitars that have suffered damage from either accident or
abuse.
In
general guitars worn by years of honest wear should not be refinished.
A touch-up of a chipped finish spot may be acceptable while a complete
over spray with clear finish would not be. For example, Fender necks will
wear but a 1950's or '60's Fender neck should be left alone. A late 1970's
with a neck that is worn to the wood and collects oil to the point of being
difficult to play well may be a candidate for a neck recolor and over spray.
Unfortunately, this decision does not take into account the aesthetics
of the future owners.
Lastly,
there are many ways to successfully refinish an instrument. The methods
described on these pages represent just one such approach. Developed through
experience, both positive and negative, these methods have served the writer
well.
Equipment
Refinishing
does not require expensive or complicated equipment. If you decide to move
beyond the entry level, as with everything, you can find an item that will
make the work go smoother. But excellent quality results are possible with
less than $20.00 worth of equipment.
If
you will be refinishing a single instrument you may want to consider the
Preval Power Unit from Precision Valve Corp. The aerosol spray unit draws
paint from an 8 oz. refillable glass container. The spray capacity of the
aerosol unit is 16 oz. Expect to use at least two units to do a complete
refinish. Using two units will also work to your advantage. By dedicating
one unit to clear topcoats and one for colors, clean-up is easier and the
possibility of spraying unwanted color specks from a not-quite-clean unit
is eliminated.
The
drawbacks of this type of unit is that long spray periods can cool the
nozzle and cause spitting. This is not a major problem with clear and lightly
tinted coats. The drops will dry into the finish and any rises will be
sanded out during final finishing. But spitting during initial stain coats
can cause spotting. The solution is to not spray for extended periods.
(This is not usually a problem in instrument refinishing).
Another
option is to use the recently introduced guitar colors in aerosol spray
cans. Currently there are approximately thirty of the most popular Gibson
and Fender colors being offered by The Guitar ReRanch. The colors are mixed
in either dye for the translucent finishes and nitrocellulose for the opaque
and semi-opaque finishes. A clear nitrocellulose for clear coating is available
in a spray version as well. The cans are offered in the standard 16 fluid
oz. size and with few exceptions, one can of color and one can of clear
should be enough to complete a body and most body/neck combinations. The
cans also incorporate a rotating fan tip for vertical or horizontal spray
situations.
As
you be come more proficient you may find yourself shopping for a system
that offers more flexibility. The more sophisticated guns allow controllable
spray patterns (adjustable circles, vertical or horizontal fans) and adjustable
air-to-liquid mixing. Standard sized automotive type guns will work but
it is difficult to "finesse" the spray down to the smaller patterns that
are sometimes needed. Also, the physical size and weight of the standard
automotive spray gun does not lend itself well to the scale of motions
and angles necessary in instrument refinishing.
A good
compromise is to use the smaller "jam" guns used in automotive finish work.
They can lay down enough spray to wet out a large area but the pattern
can be controlled well enough to do delicate shading and blending. Badger
manufacturers a unit, Model 400, which should serve well for instrument
refinish work. These midsize units were designed to be used with at least
a 1/2 hp compressor capable of at least 30psi of pressure but in a pinch
they will work with low cost diaphragm type compressors. (Using an undersized
compressor may require thinning the material sprayed). A personal favorite
is a no-name jam gun found at a garage sale. Working at 20psi pressure
from a 5 hp compressor the gun will easily wet out a top or back with very
little over spray or spray "bounce off".
If
you use a compressor the compressor should be equipped not only with a
regulator but a moisture trap as well. Moisture can whiten lacquer and
at worst can be sprayed as water droplets. Should you see small domes in
the just sprayed finish you may have sprayed water onto the surface. Do
not attempt to wipe or force dry the moisture drops while the lacquer is
wet. Wiping can destroy the color coat and force drying may cause the water
to boil resulting in greater damage. After the lacquer is dry you will
most likely find that the moisture has disappeared. Any remaining signs
will be erased with the finish finishing.
Lastly,
the newest, most efficient and easiest to use systems are the HVLP systems
(High Volume, Low Pressure) These systems operate at volumes of 40 to 60
cfm but at pressures of 5 pounds or less. They allow large amounts of paint
to be sprayed with very little over spray. In a typical compressor system
high pressure is used to pull the paint out of the paint canister through
the gun and unto the surface using the venturi effect. The HVLP system
pressurizes the paint canister with low air pressure and pushes the paint
out of the gun onto the surface. The lower pressure greatly reduces the
amount of paint that "bounces" off the surface being painted and therefore
reduces over spray. The efficiency is such that one manufacturer (TIP)
claims that a car or truck can be painted with one quart of paint. This
is about 1/4th the amount needed in a conventional system. Another added
benefit to the HVLP system is that most systems heat the air going through
the system. This means dryer air for a smoother paint application. The
HVLP systems are not cheap but there are some deals to be found on used
equipment. The systems are available in two and three turbine versions.
A two turbine system is more than enough for a single gun operation. And
lastly, If you can afford a second gun dedicate one for colors and one
for clear coats only. Clean up time will be reduced as well as the possibility
of contamination of the clear coat by stray paint chips from a previous
color.
Spot
Repair
Spot
repair can take two basic forms. First, is the drop and fill method and
second, color and clear coat. Drop and fill is just that. A chip which
did not lift the color can be filled . Although, there are some repairmen
that have advocated the use of "super glue" lacquer should be the first
choice. The reason is that super glue does not forgive well. It dries harder
and faster than lacquer and is difficult to blend in without damaging the
surrounding finish. If you decide to try super glue do not use accelerators.
They add a white tint to the fill.
First
clean the chipped spot with naphtha, let the naphtha dry and with a tooth
pick or very fine brush drop/flow a drop of lacquer into the chipped area.
Let the drop dry from three hours to overnight (best) and repeat. The filled
area should be slightly higher than the original finish. When dry the filled
area can be wet sanded. Using a small flat block (a personal favorite is
a small computer battery) wet sand beginning with #400 and working up to
at least #800. When sanding continually wipe the repair dry and check the
surrounding area for sand through. After the spot has been sanded flat
with no shiny spots in or around the drop, rub out the repair with rubbing
compound (red), polishing compound (white) and final polish with a swirl
remover. Dupont automotive compounds work well and the 3M product
" Finesse It II" works very well as the final polish.
Color
and clear coat repairs can also be made in small areas. Simply add a tinted
drop fill step to the above. The color medium should color match and must
be compatible with the clear lacquer fill coat. It is best to start with
a shade a bit lighter than the final color. It is easier to darken the
chipped area than to lighten it. Note that oil based stains will not work
with lacquer drop fills.
Area
Repair
The
next area to be discussed is repairing areas larger than a chip. Depending
on the size, color and degree of perfection you will accept, you may want
to consider an area refinish. Matching color to adjacent color is perhaps
the most difficult part of repair. Even if the repair person has the original
dye mix used on the original finish, matching will be difficult. The original
finish is colored not only by the dye but by environmental factors as well.
To demonstrate this, look under the pickguard of a vintage piece. Most
likely you will find the color is brighter and either unchecked or more
checked due to fading from different levels of light and more or less oil
or polish reaching the two areas. Add tobacco smoke and the natural yellowing
of lacquer and the problem of matching is multiplied.
Assuming
that we can polish out any offending environmental influences or live with
any color and checking difference, another hurdle to over come is "ponding".
Color can build up against the wall of original finish at the edge of the
area to be repaired. Too much color at this boundary will leave a color
line in the final finish.
Beginning
the repair, first determine the start and finish boundaries. If possible
take as the outer boundary the physical edge of the instrument. The edge
can be a right angle, sound hole, binding, pickup rout, ect. By stopping
at an edge you have eliminated one blend boundary. If an edge stop is not
possible then stop at a color. For example on a sunburst try not to involve
two colors in the repair. Also, the more the lighter areas are involved
the more difficult will be the color match.
After
determining the boundaries, try to determine the type of dye used. The
choices will be water based, lacquer/alcohol based or in some cases combination
applications of the two. ( A third coloring type is opaque lacquer ala
Gretsch ). If the damage has exposed bare wood consider if there is enough
color left in the wood to match if simply clearcoated. If there is, then
the type of dye used to stain the wood is moot. If not, gently wipe the
damaged area with a damp rag. Water based dye will stain the rag; lacquer
based dye will not. If the wood is stained with a lacquer based stain (or
colored filler) you may be better served by not disturbing the raw wood
with solvent and solving the problem with tinted over spraying. If you
are forced to remove the lacquer coat(s) and find that before wood is reached
stain is coloring the clean-up rag, then you are dealing with an originally
tinted lacquer color coat.
With
the dye type and repair approach determined, prepare the area. This may
entail simply cleaning the area with naphtha. You may also find that you
may want to feather edge the existing lacquer boundary to reduce the ponding
depth. If the repair approach is to use the original raw wood stain, do
not attempt any feather sanding. It will lighten the color.
If
water based dye is to be used directly on the raw wood, it can be wiped
or sprayed. Before either, dampen the area with water. This will even the
soak in, reduce the chance of beading and also help in reducing ponding.
Water based dyes can be wiped or sprayed. The drawback to wiping is that
large areas may streak if the dye dries too quickly during application.
The advantages of wiping are that ponding is more easily controlled and
it is more difficult to apply too much color. The advantage to spraying
is that it may be easier to lay down a more even coat. But spraying a water
based dye, especially the first coat, may bead and spraying too much at
once will almost always pond. Spraying also has no limit to the color darkness
that can be laid down.
As
with water based dyes lacquer based dyes can also be sprayed or wiped.
But because of the quicker drying speed of the reducers used with lacquers
as opposed to water, the advantages/disadvantages are reversed.
Stripping
Before
removing the old finish consider photographing the instrument from various
views. Close ups can also be helpful. Not only are photos the best way
to back up your bragging rights on a job well done but once the job is
completed the photos will allow you to be certain that the patterns of
shading and replacement of items such as pickguards are accurate.
Beware
of the chemicals used in stripping! The chemicals are caustic. Always wear
protective gloves and eyewear when using stripping materials. Also be aware
that the chemicals involved can remove not only finish but dissolve plastic
bindings as well. They can also damage labels and stain the interior of
the instrument. The first step in finishing (after protecting yourself)
is to protect all vulnerable areas of the instrument. Cover the bindings
with paper tape to protect them. (Plastic tape may melt). Taping the bindings
will also make clean-up easier. Before using paper tape be certain that
the tape will not pull off the original finish. Paper tape also tends to
adhere more tightly the longer it is left on a surface. If in doubt, do
not tape over any finish you do not plan to remove. Automotive color supply
stores offer an 1/8" fine line tape that will cover most top bindings in
one pass (sides in two) and is thin enough to navigate the tight radius
curves. (You may find that the waist is best taped with a separate strip
and then over taped). 3M manufactures a tape which performs this function
well. The 3M brand part number is #233.
To
protect the interior of the instrument, stuff newspapers into the cavity
through the sound hole(s). Tear the sheets into 1/4 size pages to make
removal easier. Stuff more than you think is needed. If not sufficiently
packed the paper can shift and leave open areas. Ruining an otherwise clean
interior or label is inexcusable.
When
stripping always try the most forgiving stripping medium first. Lacquer
reducer will remove many finishes, is less of a danger to you ( be sure
that your work area is well ventilated and that there are no open flames
in the area) and is less likely to attack the bindings. It is, however,
slower to work than the "Strip Ease" paste type of remover. Therefore,
a combination method, while not the fastest, may be the best.
Use
a "Strip Ease" type stripper in the areas which are not close to the vulnerable
bindings. Paint the stripper onto the finish per the manufacturers instructions.
After allowing the stripper to soften the finish, a 1/2" to 1" stiff paint
brush can be used in a short "pushing" motion (as opposed to the pulling
motion normally used when painting) to help lift the finish. Fine (#0000)
steel wool rinsed in water can also be used to remove the melted finish.
An alternative to steel wool are the plastic mesh pads made by 3M expressly
for stripping. Although more expensive they can be rinsed with water and
reused.
Work
from the inside of the area pushing out toward the binding. Wipe the end
of the brush often being careful not to drop stripper on the "good" areas.
When the area near the binding is reached (about an 1/2" away) use lacquer
reducer for the remaining finish. Paper towels moistened with reducer may
work best for you. The work will be slower but potential for damage is
reduced. Be aware that while not as caustic as "Strip Ease", lacquer reducer
can still melt bindings if left in contact too long. Also, if you are planning
to save the color of the original bindings then particular care is needed
when the binding edge is reached. Be aware that if too much reducer is
used it can seep under the protective tape and damage the bindings.
ALL
of the old finish in the area to be refinished must be removed. If not
removed the new stains will not evenly color. When all the finish is removed
wipe the area clean with lacquer reducer. Then wipe the area with naphtha.
Should
you ever have the unfortunate job of stripping a polyurethane finish, I
have found only one chemical stripper which will remove poly; AirCraft
Remover by Kleen Strip. It can be found at most automotive paint supply
stores. Be aware that should you decide to use A/R, it is deadly to plastic
bindings. Protect the bindings and if possible strip with A/R only up to
near the binding area and use lacquer thinner or sanding to remove the
finish adjacent to the bindings. One trick; on stubborn finishes, cover
the area being stripped with a plastic garbage bag to prevent the stripper
from evaporating. This will give the stripper a longer working time. Test
the bag first to be sure that it is not attacked by the stripper although
most bags do not seem to be affected.
Forward to Wood Preparation, Mixing, Spraying, The Rule of Threes, Final Polishing, Applying Solid Colors, Metallics and Blonde, and Troubleshooting
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