Transform virtually any metal surface from a dull rough finish to a lustrous
shine! The key to that satisfying gleam is knowing where to start and understanding
the difference between polishing and buffing. Often novices use the terms
interchangeably.
Polishing removes a heavy amount of material, like during sanding or grinding.
Buffing is the process that brings out the actual full brilliance of a part.
Parts with dented or scratched surfaces will first require some conditioning
before buffing can be effective. Here we will discuss how to prepare parts
for buffing.
Difficult to replace stainless steel trim is a perfect example since it
is almost never in a ready-to-buff state. Scratches and dings may be removed
in a similar manner to dents on a car body, only on a smaller scale. Use a
Mini Anvil
and Trim Hammer to
raise
the dent. Blows of the hammer spiral in toward the center to minimize stretching.
Once the surface is relatively straight there are five methods to make the
part smooth enough for buffing. The most time consuming is to block sand or
file the part by hand, allowing for the greatest control. Eastwood's Expander
Wheel (13079)
used at up to 2400 rpm with premium grade 3-M Trizact
Abrasive Bands will also level the surface and maintain the flatness of the
surface without rounding edges. This band serves the same purpose as our regular
abrasive bands except it's available in finer grits and cuts more consistently
throughout its longer life. Trizact Bands can be used to get relatively flat
surfaces smoother quicker than any other abrasive, reducing buffing time.
Scotch-Brite
Bands are also for use on the expander wheel, but due to their mesh-like construction
work better on slightly contoured surfaces. Edge marks on the part are virtually
eliminated due to the softer construction of these bands. For smoothing highly
contoured surfaces, Eastwood's Greaseless
Compound
(13129,
31,
32,
94)
is the most effective. These compounds are applied to either Spiral Sewn or
Loose buffing wheels. Available in 80, 120, 220, and 320 grit, they convert
your buff into a flexible grinding wheel. Tight access areas can be polished
and smoothed with
Eastwood's
Abrasive Rolls (available in cylinder and tapered formats from 80 through
320 grit) and can be used on tapered mandrels ranging in length from 2 ¾"
- 6". Use the shortest
mandrel possible since excessive side loading will more easily bend the longer
mandrels. Felt bobs used with greaseless compounds mentioned above act as
another alternative to using abrasive rolls.
The Vibratory Tumbler Systems
Eastwood's vibratory
tumbler systems can be used for polishing and buffing small parts, and
are an effective alternative to hand finishing. The vibratory type of tumbler
works up to 25 times faster than rotating tumblers. Actual process time will
vary from a few hours to a few days, depending on the condition of the parts
and the finish desired. Parts to be tumbled should be free of grease, oil
residues and paint coatings. The tumbler load should consist of 30% parts
to 70% media, without exceeding the maximum rated tumbler load of approx.
3 lbs. for the small tumbler and 6 lbs. for the large tumbler. The pyramid
shaped Green
Rust Cutting Media is used both in the smaller bowl for the small tumbler
or the single heavy-duty bowl included with the larger tumbler. Add enough
water to just cover the media without creating standing pools of water. It
usually takes between 5-12 hours to de-rust and clean moderately rusty parts.
If a high shine is desired, the parts can then be placed in the bowl with
the Dry
Shine. This media will impart a high luster in 24 hours to a few days.
Which Buffing Motor is Right for You?
When selecting a buffing
motor a number of factors need to be considered. If the buffer is predominantly
for buffing metal, choose 3600 RPM; if you'll be predominantly buffing plastic,
1800 RPM is preferred. More powerful motors yield faster results because larger
diameter wheels and/or multiple wheels can be used on the same shaft. The
lower power motors will get the job done but will take more time. For buffing
light pieces of stainless steel trim, many prefer a smaller buffing wheel,
which can be used on the small buffing motors or modified by making a small
cut north, south, east and west around the arbor hole to fit the larger buff
motors.
All of the buff motors we sell feature sealed cases and long shafts supported
by ball bearings. The Eastwood Buffing
Motors represent remarkable value and performance that will nicely suit
most hobbyist and professional needs. The Baldor Motors have long been the
industry standard for excellence and offer slightly longer shafts for improved
maneuverability.
Mandrels and Adapters - Using an Existing Motor For Buffing
If you prefer to use an existing motor for polishing and buffing operations,
Eastwood
sells
a wide variety of Motor
Adapters to fit motor shafts from 3/8" to ¾". The 1/2"
and larger mandrels are available in right- and left-hand thread. To determine
which thread you need, examine the unit to see if the shaft is to the right
or the left of the motor. If your shaft is to the right, use a RH adapter,
and a LH adapter if the shaft is to the left of the motor. The Wheel Arbor
(13064)
is used to mount our smaller wheels with ½" mounting holes to
your drill or die grinder. If using this adapter with a drill, be sure the
drill spins at least 2500rpm -- low rpm is the leading cause for difficulty
in transferring compound the wheel. For our Mini
Buffs (1-2" diameter) we have 2 mandrels - ¼" (13054)
1/8" shank (13063).
These 2 sizes allow the buffs to be used with most die grinders.
Getting Ready to Buff
Once the surface is smooth enough to buff (i.e., 220 grit or finer for soft
metals like aluminum, brass, copper, and pewter; 400 grit or finer for steel
and stainless) the buffing process can begin. As mentioned earlier in the
polishing/preparation section, Trizact
Bands can be used to substantially speed up the buffing process. When using
the A-30 (700 grit) and A-16 (12000 grit) bands on aluminum or other soft
metals, use either Eastwood Tripoli
compound or Eastwood Grinder's
Grease on the Trizact band. Running these fine belts dry can pull grains
of metal from the part and drag them across the surface resulting in a rough
finish. Using the Trizact bands saves substantial time and eliminate one or
2 buffing steps.
Buffing Safely
Buffers spin at a high RPM (usually 3600 rpm), which is more than enough
to launch parts across the room or into you if the part is not held properly.
Make contact with the lower (4:00 position when viewed from the left) portion
of the wheel. The wheel should pass over corners and edges, not toward corners
and edges. Hold the piece tightly and apply light (about 2 lb.) pressure against
the wheel. Do not insert your hand or fingers into openings. Practice how
you will hold the piece against the wheel before starting the motor. Once
you're satisfied you can hold the part safely, you're ready to put on your
gloves, dust mask and eye protection and begin buffing.
To
apply the compound to the wheel, tear down the cardboard tube and hold the
exposed compound against the wheel for about 2 seconds. You'll see how the
wheel takes on the color of the compound. You'll also notice how the wheel
turns black almost immediately when you start to buff. This black build-up
is not harmful to the wheel or the part being buffed. Rake
the wheel if you notice excessive metallic build-up or at the start of the
day to prevent scratching the surface.
As you progress from one compound to the next finer grit remember to clean
any residue with Eastwood PRE
Painting Prep (10041Z),
Metal
Wash (10120),
or hot water and detergent and change the angle by 90 degrees (or as close
to 90 as the configuration of the part allows). Before you stop to inspect
your work, take a few passes with the direction of rotation. This technique
will help remove fine scratches for a better shine. In the finishing industry
a "black finish" represents the highest reflectivity. If the buffed
surface can reflect black without showing any fine scratches, then the best
finish has been achieved.
Preserving The Shine
Buffed surfaces will stay oxide free longer than rough metal, but in many
cases the durability of the shine can be enhanced with the use of clear coats.
Stainless steel, gold, and platinum do not need to be top coated with a clear,
but brass, copper, aluminum, silver, pewter and most other metals will benefit
from a clear coat. The most durable clear to use is Eastwood's Super
Gloss Clear (10286)
HotCoat powder. Some types of brass, bronze and steel can significantly oxidize
when exposed to the curing temperature, in which case Eastwood's Diamond Clear
Gloss for Bare Metal (10200Z
in Aerosol form) and (10189Z
in pint form) can be easily applied after degreasing for durable oxidation
prevention.