Measuring Up the Product- Part 1
Need to evaluate powder coatings offered by different
manufacturers? Some products may appear to be identical but have different
prices. Which is the better value, which should you buy, and which product best
suits your particular need? The following is information on evaluating powder
coatings to help answer the above questions.
Terms to understand
for powder evaluation:
Film thickness is
the after-cure depth of the coating, usually expressed in mils (thousands of an
inch). The amount of protection needed
and required appearance determine the film thickness needed.
Hiding is the
ability of a coating to mask the color or pattern of the surface to which it is
applied. Therefore, the underlying
surface should not show through the coating unless clear or translucent
coatings are being used.
Coverage is the
amount of surface area a specific amount of powder coating will spread at the
required thickness. It is usually expressed in ft²/lb
of powder at a given thickness.
Specific gravity
is crucial in order to calculate the covering power of the powder and thus the
actual coating cost per unit area covered at a given film thickness. Specific gravity (SG) is the density
of a formulation relative to water weight. Powder coatings range in SG from
approximately 1.2 to 2.0. A powder with an SG of 1.2 is going to be
much lighter and typically easier to fluidize and spray than a powder with an
SG of 1.7. This allows for a more even film build, resulting in fewer
rejects and errors. Another advantage from using low-SG powder coatings is the
ability to cover more part area with the same amount of powder. So, even though
a powder may have a lower price per pound, a material with higher filler
content and therefore a higher SG will cover fewer square feet and thus may
have a higher total cost.
Look for an upcoming blog on Measuring Up the Product- Part 2 for continued information on
powder evaluation to determine which products provide the best value. For more information like this, please see or download our powder coating technical guide on our website.
Comments
Post a Comment