Simply put, powder is paint applied by a different method.
A method ideal for coating all sides of your new gate or fencing
evenly. Most all powder paints start life as a liquid, very
similar to spray paint. This is where the resin, various components
and pigments are mixed into a homogenous mass. From there they
are partially cured, converted into a solid, extruded and ground
(cryogenically) to the desired level. Color matches are much
more difficult with powder, as once it is made into the powder
coating, it is done, versus paint that can have additives used
to give desired effects (color tint, gloss, leveling, texture
There is a misconception that powder is some space age material
akin to high tech ceramics and carbon fiber. That’s generally
not true. Powder is just another method of laying down an organic
film, i.e. paint. A powder coating of epoxy will have the same
basic properties such as poor UV (sunlight) resistance as a
liquid paint. For fencing and gates, resin types are limited
to Acrylic, Polyester, TGIC Polyester and Urethane resins. These
are the systems that have the best UV resistance which equates
to longer finish retention outdoors.
Most powders have very good chemical and corrosion resistance,
but again it is resin specific. Epoxies have excellent chemical
resistance. Polyesters and Urethanes are typically used for
aesthetic coatings on steel/iron Fencing and Gates and have
good resistance. Powders do have an advantage over liquid paint
here. If you can, imagine how a liquid coating dries or cures.
Solvent has to escape from the film as it "dries down".
If you were to look at this under a microscope, you would see
a bunch of little pinholes that look like small volcanoes. This
is an avenue for moisture and chemicals to penetrate the film
more quickly, accelerating corrosion. Powder simply melts down
at cure temperature and (usually) isn’t prone to pin holing.
Castings are the exception and are coated after pre-heating
so that the pores of the casting don’t "out gas"
during the cure cycle.
Powder coating was introduced to the United States in the late
60’s. It started to really take off in the mid 70’s
and has steadily gained in popularity for a number of reasons.
Powder coating is environmentally friendly. Powders contain
no solvents and thus have very low air emissions when curing.
Typical powders have a VOC (Volatile Organic Compound) rating
of <1.0 pounds per gallon versus liquid paints in the range
of 2.5-7.0 pounds per gallon. There is very little waste with
powder. Powder overspray can be collected and reused, rather
than just thrown away as with paint over spray.
How is it done?
Powder is sprayed (and in some cases dipped) on parts where
it clings by static electricity. From there it is baked, where
it melts, and evenly flows and cures.
color matching is not offered in powder .
It simply costs too much to make a batch of powder for one application.
Our coater has a good selection of "sample panels"
from the powder manufacturers. Most commercial fence and gates
are coated in low gloss black.