For most autobody painters, buffing is a small
part of their duties during the work day. On the other hand, the
technicians in the detail department spend the bulk of their time
every day wielding a buffer. As a general rule, then, the detail
people will be faster and do a better job than the painters will.
The difference: practice. If your job was to buff and polish cars
all day long, you’d get pretty good at it, too. The full-time
detail tech can use a polisher that runs at high rpm and use virtually
any style of pad and any brand of compound and still get a nice
looking job.
If you don’t feel as confident about the buffing
and polishing you must do to get the customer’s car in acceptable
shape for delivery, the following tips from the detail pros may
help.
We’re going to break the buffing operation
down to four parts: the vehicle, the tools, the technique and
the compound/polish products. Far too many autobody painters use
the same combination of the four variables on every car. Better
results will occur faster if the painter is willing to change
some of the variables, depending on the problem.
The Vehicle
Most polishing is done to remove paint flaws
that will prevent the customer from taking delivery of the vehicle.
Years ago, the car manufacturers didn’t turn out the perfectly
clean paint jobs that are the norm today. I remember being called
to a dealer customer back in the late 1970s to help satisfy a
finicky consumer. The dealer’s customer was unhappy with the paint
job on his brand new automobile – it had six or eight visible
dirt specks on the flat panels and a pretty good size run in the
left rear quarter – all fresh from the car manufacturer. Naturally,
the customer wanted something done. The dealership’s solution:
Take the customer up to the showroom and find similar paint flaws
on every car on the sales floor and then persuade him that a poor
paint job was the best he could expect.
These days, the car manufacturers are routinely
producing perfect looking paint jobs; the vehicle owner won’t
stand for anything less from your collision repair work.
The most common paint defects are dirt in
the finish, orange peel and die-back – all unique to a repainting
operation. How do you rid customer vehicles of such flaws and
perfect your paint job?
One of the best tips to make buffing and polishing
move quickly is to have a designated place to do them. If your
shop has no special area for polishing the painted cars, you may
be causing yourself more work.
An obvious advantage is having all the tools
and chemicals in one place – saving a long hike around the shop.
Segregating the polishing operation will likely keep your shop
cleaner, too. If the only place in your shop to polish cars is
directly in front of the spraybooth, you’ll be throwing all sorts
of dirt into the paint job currently being sprayed. A designated
polishing area should also have very good lighting. Just like
painting, it’s hard to do a good job if you can’t see.
You also need to remember a few polishing
rules to do a good job. One rule that often gets bent in a busy
paint shop is to only work on a cool surface. If the car has just
come from a 170-degree F force dry or has just been pulled in
from the sunny parking lot, the paint will mar or stain very easily
because it’s hot. To determine whether the surface is cool enough,
the first test should be to put your hand flat on the painted
surface. If there’s any heat, hold off until the paint cools to
the touch.
Also, the finish needs to be clean. The sanding
dust that has settled on the paint while the vehicle was parked
in the shop will likely cause deep scratches. If the surface isn’t
completely clean, how will the tech see the paint defects that
need to be removed?
The Tools
If you buff and polish cars all day long,
you can probably use whatever speed you want up to 5,000 rpm.
(Be really careful of the styling lines at this speed – the thin
layer of paint on those edges is gone in a blink at high rpm.)
If you aren’t the buffing whiz you wish you were, use lower speeds
on the polisher. It may take a little longer, but it’s much easier
to master.
Running the polisher at low rpm keeps the
heat buildup down. Friction of the spinning pad rubbing against
the paint causes heat, and too much heat will make the job harder
to complete. As a general rule, sander-grinders run at 4,500-6,000
rpm. This high speed keeps the grinder disc from loading up with
melted material, which is thrown off the whirling disc. Most polishers
run at 1,000-3,000 rpm, and this slower speed makes it easier
to control the heat. Less heat is needed when cutting the finish
with compound. When trying to polish back to a high gloss, a higher
speed can be used.
For your low-rpm polisher, there are four
basic types of pads. Whichever style you use, make sure it’s centered
on the backing pad. Out-of-balance pads will make the tool hard
to control.
Since labor time is the most expensive thing
in any paint shop, a quick-change backing pad is an absolute must.
The coarsest cutting pad is called a compounding
pad. This style has wool yarn (or wool-acrylic mix) twisted into
miniature rope for strength. The abrasives in coarse compounds
are very destructive – after all, they’re tough enough to cut
the imperfections out of the paint. The wool is twisted to resist
being cut apart by the compounds. Polishing pads have loose wool
(or manmade fiber), which will do a better job polishing out the
swirl marks left by the coarse compounding pad.
Foam pads are available in both a coarse (cutting)
style and a fine (polishing) type. Each manufacturer thinks it
has the best solution to the same problems. Issues like open-cell
or closed-cell foam, all-wool or all-acrylic yarn, curved edges
or a rippled texture are all features and benefits of some particular
brand. Which is best? That call is up to you. Try them all before
you decide, but remember: The best test isn’t which is cheaper
– it’s which style pad is faster in your situation.
Whatever your rpm or pad, always remember
to keep the pad flat on the surface – it spreads the force out
evenly. An electric polisher weighs somewhere around 10 pounds.
A 7 1/2-inch pad has about 50 square inches of area; that works
out to about 3 ounces of weight per square inch of pad surface.
This light, steady pressure is just what the doctor ordered for
fresh paint work. If you tip the polisher up on edge, like a grinder,
the tool still weighs 10 pounds, but the force is spread over
a smaller pad area. This can triple the amount of force on the
pad even if the operator doesn’t push down, causing heat buildup.
The Technique
To achieve that perfect finish, one sure-fire
tip is to only work in small areas. Rather than smear compound
all over the entire hood, only work on a 1- to 2-square-foot area
at a time; it’s easier to keep the surface lubricated with polish
and easier to make sure the imperfections are all removed. Keep
the tool moving to prevent a heat buildup and to prevent burning
the paint.
If you’ve watched an expert polish a car with
his product at a trade show or at a demonstration in your shop,
it’s pretty flashy when he pulls the very last dab of compound
or polish off the panel with the last pass of the polisher, leaving
a shiny clean surface behind. That’s showboating; it’s much easier
for most of us to carry a clean towel and simply wipe off the
excess polish with it. Granted, it isn’t as snazzy, but it’s certainly
easier to master and is often faster.
By wiping away the excess compound or polish
on the small area that you’re currently working on, you can tell
if the imperfections are gone. If they are, wipe off the rest
and move to the next small area. If the imperfections still remain,
keep buffing.
Another tip that might help is to clean up
the spatter or sling as soon as possible. Knowledgeable painters
know to spread the polish or compound around the surface with
the pad before pulling the trigger on the polisher, which will
fling compound all over the car, the operator and the shop. Even
with a careful application of compound to the paint finish, some
excess will be flung into the door jambs and seams.
Cleaning this spatter out is faster if you
use a special detail brush. These special brushes are basically
paint brushes with half the length of the bristles cut off, making
it easy to sweep the specks of polish off the car. If your cleanup
crew spends too much time scrubbing the compound spatter off the
vehicle after it’s polished, look for another brand that will
cut as fast, but clean up quicker.
The Products
Compounds and polishes are basically paste
sandpaper. Just like sandpaper, they come in a variety of grits.
The advent of clearcoat finishes has caused most painters to quit
using the old-style, heavy-cut compounds.
The object on a fresh paint finish is two
fold: to remove the defects and to polish back to a high gloss.
Years ago, we tried to do both with one product. The coarse abrasive
in the compound would cut the defects out of the paint, but it
left a scratch that was difficult to remove. When clearcoats became
the norm, the customer could see the scratch plainly because the
light shown into the finish and exposed the bottom of the scratch
as well as the top.
For most paint shops, the polishing job can
be done in less time if the paint defects are sanded out with
fine-grit sandpaper before polishing back to a gloss. Rather than
using the compound to level the paint, sand it flat first. Use
the finest grit of sandpaper that will remove the defect; the
shallower the sand scratch, the easier to polish it out.
If you sand the finish wet (which provides
the truest cut), make sure to keep the sandpaper in water for
at least 20 minutes before you begin. Soaking-wet sandpaper does
a much better job than simply lubricating the panel with a squirt
of water and using the paper dry. Whether you sand in straight
lines or cross cut, or use hard or soft rubber sanding blocks
is a matter of personal preference.
If you’re not happy with the results of your
current products, try something different. There are a bewildering
array of compounds and polishes for sale in our market. Some products
are better suited to a cleanup and detail operation than to a
paint shop, but there are literally hundreds of other products
specifically intended for autobody use. Products that are water
or oil base, have easy cleanup, work well with foam pads, are
great on orange peel and save steps are advertised everywhere.
Every vendor’s product looks great at the
trade show, but the proof is how it works in your situation. Try
all the products; buy a pint of four or five different ones and
try them in your circumstances. The features and benefits of a
particular brand are best determined in your own shop environment.
Don’t be afraid to mix brands, either.
The End Result
When choosing the tools, techniques and products
that will work best in your shop, your concern should be how quickly
you can get your paint work perfect enough to deliver back to
your customers. If it happens using one vendor’s products or with
a mix of brands, tools and pads, so be it. The best system is
the one that, with a lot of practice, gets the cars out your door
with a flawless finish – fast.
Mark Clark, owner of Clark Supply Corporation
in Waterloo, Iowa, is a contributing editor to BodyShop Business.
