What is Powder Coating?
So, you've heard of it, but, you're not quite sure exactly what powder
coating is. According to the Powder Coating Institute's web page,
"Powder coating is an advanced method of applying a decorative and
protective finish to a wide range of materials and products that are
used by both industries and consumers. The powder used for the process
is a mixture of finely ground particles of pigment and resin, which is
sprayed onto a surface to be coated. The charged powder particles adhere
to the electrically grounded surfaces until heated and fused into a
smooth coating in a curing oven. The result is a uniform, durable,
high-quality, and attractive finish." There, so now you know! Or do you?
Most powder coating guns,
10-30 PSI Powder Coating System
apply a negative electrostatic charge to the flour-fine powder (that
magical mixture of "pigment and resin"). This charge is high voltage; up
to 25,000 volts (100,000 volts on industrial guns), but fortunately
very low amperage (the amps are the part of electricity that can really
hurt you). Since this powder is made of resins, we know that it falls in
the general classification of "plastics". As a member of the plastic
family we know that it is a poor conductor of electricity. So once the
particle is charged, it gives up that charge very reluctantly. This is
what causes the powder to "cling" to the substrate being coated. The
negative ions in the particle slowly fight their way to the positively
charged substrate. This slow flow of ions from particle to substrate is
what holds the particle on the substrate. Putting it another way, think
of the positively charged substrate as "sucking" the negative ions out
of the particles, causing them to stick.
Why Is Powder Coating Better?
More Durable - Powder coating gives consumers, businesses, and industry
one of the most economical, longest-lasting, and most color-durable
quality finishes available. Powder coated surfaces are more resistant to
chipping, scratching, fading, and wearing than other finishes. Color
selection is virtually unlimited with high and low gloss, metallic, and
clear finishes available. Thanks to the UV resistance of many of the
powders, colors stay bright and vibrant longer. Texture selections range
from smooth surfaces to a wrinkled or matte finish, and rough textures
designed for hiding surface imperfections.
Protects the Environment - Powder coating is also highly protective of
our environment. While liquid finishes contain solvents which have
pollutants known as volatile organic compounds (VOCs), powder coating
contains no solvents and releases negligible amounts, if any, of VOCs
into the atmosphere. Thus, there is no longer a need for finishers to
buy costly pollution control equipment. In addition, most powder coating
overspray that does not adhere to the part can be retrieved and reused.
Although this is not always practical for many low-volume users, this
can virtually eliminate the waste commonly found in liquid finishing
processes.
Saves Money - Elimination of VOCs and reduction of wastes saves money
and helps companies comply more easily and economically with the
regulations of the U.S. Environmental Protection Agency. In fact, one of
the major elements in expanding the market for powder coating has been
the implementation over the past 30 years of stringent air pollution
control legislation.
Where Is Powder Coating Used?
Appliances - The appliance industry benefits from powder coating on
front and side panels of ranges and refrigerators, washer tops and lids,
dryer drums, air-conditioner cabinets, water heaters, dishwasher racks,
and cavities of microwave ovens. Powder coating has also replaced
porcelain enamel on many washer and dryer parts.
Architecture/Building - The architectural and building market powder
coats aluminum extrusions used on frames for windows and doors and
modular furniture. Many highway and building projects use powder coating
on light poles, guard rails, signs, posts, and fencing.
Automotive - Henry Ford once said, "You can have a Model-T in any color
you want. So long as it's black." For an industry once focused primarily
on manufacturers' needs, powder coating is transforming the automotive
industry with faster production times and lower operating costs, plus
irresistible value propositions for consumers. For years, conventional
liquid coatings were the standard for the automotive industry. But these
coatings can emit dangerous VOCs at their application stage. Powder
coatings eliminate most environmental concerns and the need for costly
waste disposal systems. Because powder does not run or drip, the result
is a uniform, superior-quality finish.
Conversion from liquid to powder clearcoats for auto body exteriors
is moving rapidly. Powder topcoats resist acid rain, the sun's
ultraviolet rays and road and weather damage, helping cars retain their
"showroom look" much longer and improving their resale value. BMW and
Volvo are using it on their new model cars, and GM, Ford, and Chrysler
have formed a consortium to test this technique on their production
lines.
Powder coating has made substantial inroads as a primer for car, van and
pickup truck bodies in the United States. Auto body primers in colors
will be next.
There is huge market potential for high-heat resistant powder coatings
on aftermarket mufflers, which resist corrosion, protect against nicks
and prolong the life of the muffler. Some companies are already applying
heat-resistant powder to aftermarket mufflers, and the new-car market
is thought to be two or three years away. Powder coating is also applied
to wheels, grilles, bumpers, door handles, roof racks and exterior and
interior trim. "Under the hood" uses include oil and fuel filters, brake
pads, engine block casings, suspension components and radiators. Pickup
truck and SUV owners can purchase powder coated side steps, bed rails,
luggage racks and toolboxes as dealership add-ons or in aftermarket
stores and catalogs.
Performance car owners can find powder coated special suspension units,
carburetor parts and valve covers, plus flashy rear-view mirror mounts
and other exterior adornments.
Everyday Products - There are also innumerable everyday uses for powder
coated products such as lighting fixtures, antennas, and electrical
components. Farmers have powder coated tractors and farm equipment.
Fitness buffs powder coat golf clubs and golf carts, ski poles and
bindings, snowmobiles, bicycles, and exercise equipment. Shop owners
have powder coated display racks, shelves, store fixtures, and vending
machines. Office workers use metal furniture, computer cabinets,
mechanical pencils and pens, thumbtacks, and other desk accessories that
are powder coated. Parents have powder coated baby strollers, cribs,
metal toys, and wagons. And home owners have lawn mowers, snowblowers,
barbecue grills, patio furniture, garden tools, electronic components,
bathroom scales, tool boxes, and fire extinguishers which benefit from a
powder coated finish. The powder coating boom has just begun - expect
more exciting uses in the near future.
