Solids by Volume
The percent of solid material remaining after the coating has completely dried. Measured by applying coating on a surface; measuring while wet then measuring again 24-48 hours later.

This is one of the most commonly misunderstood terms on a product data sheet. Solids by volume is critical to understanding dry film thickness.

Often times you will see spec writers using solids by volume to differentiate one coating from another, or better said, to rule out certain coatings. The solid content of a coating has nothing to do with the quality or performance of a coating. Let’s use acrylic coatings as an example. American WeatherStar High Tensile Acrylic 211 has a 55% solids content. The 211HT is equal to or better than any acrylic coatings on the market today. However, if you look hard enough, you can find acrylic coatings offering 65% solids content. It would be easy and inexpensive to increase the solids content of the 211HT with fillers, but then we would be giving up quality by lowering elongation and tensile strength.

Another example where solids content is often used incorrectly is with silicone coatings. American WeatherStar offers two silicone products with similar performance once cured. Silicone 410 has 69% volume solids whereas the High Solids Silicone 412 has 96%. We sell 10 times the volume of 410 over 412, even though it has lower solids. This is because it’s easier to work with, and it has better adhesion qualities than any of the high solid silicones on the market today. Once cured, both have great physical properties. The high solids product cost more per gallon but is slightly less expensive on a per dry mil basis. We see this as a contractor preference issue. American WeatherStar has great confidence in both products.