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?
, 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 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.
