Powder
Painting
At a glance, it is difficult to visually see the difference between a
piece that has been powderpainted and one that has been spray painted.
Both methods essentially accomplish the same goal of covering the piece
with a uniform color, usually for cosmetics or to stop oxidation.
The similarities between the two basically end there. While spray
painting is a one step process, powder painting requires a rather
complex procedure. However, not all
materials can be powderpainted. The process requires very high
temperatures that will melt most plastics. Also, the part must be
able to hold an ionic charge, so this reserves powderpainting to be used
nearly exclusively on metals.
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Probably the most important part of the entire process is the
preparation of the piece. First of all, the component must
have all dirt, grease, paint, etc removed. Powderpaint
sticks well to metal, but not so well to other things.
Pressure washing, sand blasting and dipping are some methods to
strip the part. Dipping the entire chassis is discussed in
the products section. After being stripped, the piece is pressure
washed with a phosphoric acid solution to etch the metal.
Note the look of the metal after the pressure washing. |
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After being etched, the piece is placed in an oven and heated to
remove any moisture in and on the metal. Any section of
the part that should not be powder painted is covered with a
fiberglass tape or filled in with a silicone plug. This
will prevent any powder from inadvertently getting into any of
these places, and these materials will not burn when heated.
Note in the trunk area of the bottom picture there are some
studs that have been taped. |
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When all moisture is removed from the metal, an electrode is
clipped on to give the piece a negative charge. The powder
is then sprayed on completely dry. Powder is sprayed on in a very similar fashion to conventional
paint. The positively charged powder ionically sticks to
the negative metal. The ionic charge ensures that the
entire piece gets covered; powder will find cavities and
orifices that normal spray paint cannot. The powder
contains among other things, a polyester which is responsible
for the durability. Actual composition of the powder will
depend on temperature, texture and color. The entire
process might also be changed slightly based on the type of
finish desired; for example, the yellow shown is applied while
the chassis is still warm, and a second coat is applied after
the first is "baked." |
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Once the part is sufficiently covered, it is placed into the
oven a second time. The temperature is raised to around
350 degrees F. Once the oven reaches this temperature, the
paint is baked for about 20 minutes, and the powder essentially
melts into a liquid. because the paint clings to the metal
ionically, powderpaint will not build up in one area and run as
it becomes liquid. even when at maximum temperature, the
powderpaint remains quite thick and viscous and won't drip down
the piece from gravity. The piece is then removed from the
oven and allowed to cool naturally back to room temperature.
During this time, the powder re-solidifies and produces the
smooth, thick look that is apparent with all powderpainting. |
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After the base color is applied, it is sometimes desired to
apply a clear coat for a glossy finish. The clear coat is
basically just another color of powderpaint and the process is
the same as for a color. As seen in the pictures, the
clear coat goes on as an opaque white; this is very helpful in
making sure the entire piece is covered. The clear is
baked, just like before, and when the piece is removed and
cooled it has a deep gloss and looks wet even though it is dry
and durable. |
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This process is very involved compared to spray painting, but
the result is a very durable and smooth run-free finish that is
not possible with spray paint. Powderpainting is highly
desired for almost every part of the car. Powderpainting
the chassis significantly decreases scratches and signs of wear
from getting in and out of the car. Engine components see
very high temperatures that will cause ordinary spray paint to
flake-off; while powderpaint is able to withstand the heat.
We've powderpainted almost every piece on a car, wiper arms ,
roll bars, brake calipers, wheels, tow hooks, the list is
endless. |
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For more information on
powderpainting or to get some powderpainting work done, contact us at
the phone number above, or send us an e-mail. |
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