Understanding paint volume solids provides many benefits:
- It allows you to compare the true cost of different paints.
- It allows you to predict how much paint must be applied to obtain adequate coverage.
- It allows you to control the quality of the paint job.
- It allows you to avoid production delays because thick layers of paint dry more slowly.
Understanding paint volume solids begins by recognizing that as paint dries some components evaporate while other components are deposited on the surface. What evaporates is mostly the thinner, either water or a solvent which has been added to the paint so that it can be applied. In the simplest terms, the volume solids are “what’s left after the paint dries.”
Paint manufacturers express “volume solids”* as a percentage of the total volume. This information can be found on the paint’s technical data sheet and sometimes on its label.
For liquid coatings the “paint volume solids” can vary widely depending on the type of paint and its purpose. For example:
|Paint Type||Vol. Solids %|
|Architectural Paints **||35-45%|
By understanding paint volume solids you can calculate how much of each gallon of paint remains on the surface to perform its function. Higher volume solids are not necessarily better than lower volume solids, it really depends on the type and purpose of the coating, and higher volume solids usually means a higher price per gallon.
There are many benefits in understanding volume solids of coatings. In future articles I’ll discuss how to convert volume solids to spread rate and dry-film-thickness, but for now it’s worth remembering that volume solids differ between coatings and knowing the difference can provide many benefits.
*Don’t confuse “volume solids” with “weight solids”. Volume solids predicts how much area a paint will cover and weight solids indicates the weight of the non-volatile ingredients.
**Low VOC paints may have higher “volume solids”
By Bob Lyons, CARBIT Paint Co., LLC.