Volume Solid (VS)
Definition - What does Volume Solid (VS) mean?
A volume solid (VS) is a measure of the volume of solid film-forming ingredients in a can of paint, or the material that is left behind when the paint has dried. In other words, it is a measure of the paint's true volume. The volume solids of a paint is a reasonably good measure of the paint’s quality compared to other brands.
The measure of volume solid allows:
- Comparison of the true cost of different paints
- Prediction of how much paint must be applied for adequate coverage
- Control of the quality of the paint job
- Avoidance of production delays
Corrosionpedia explains Volume Solid (VS)
A volume solid is expressed as:
- VS = (Volume of pigment + Volume of solid binder) / (Total wet paint volume) × 100
The 100 is in the equation because volume solids are always expressed as a percentage.
The pigment and binder of paint form the volume solids of the dry paint film after the vehicle and some additives evaporate, and is considered the real volume of the paint. Typical volume solids are 30–45% of the paint volume. This is an important concept when using paint industrially to calculate the cost of painting.
For example, if paint is applied in a wet film at a 100 µm thickness, and the volume solid of paint is 50%, then the dry film thickness will be 50 µm as 50% of the wet paint has evaporated.
It may be used to determine the dry film build of the paint when it is applied at specified spreading rates. Volume solids can be altered by addition of thickener and solvent. Thick paint is not always high in volume solids. When choosing between paints, careful analysis of volume solids versus price is necessary, as well as considerations about color durability, environmental friendliness and so on.
The volume solids of a paint may be increased simply by leaving water or solvent out of the formulation. The problem then is that the paint becomes too difficult to apply. The thickness of paint after it has dried can be measured using a dry-film-thickness gauge.