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?
Eastwood’s
HotCoat® Guns
Like most powder coating guns, 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 of the low-volume users we service,
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 clear coats 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 use golf clubs and
golf carts, ski poles and bindings, snowmobiles, bicycles, and
exercise equipment that are powder coated. 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,
snow blowers, 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.