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.