T.S.R = Theoretical Spreading rate. The pure yield per square metre, based on the volume solids and dry film thickness. The theoretical rate takes no account of losses - eg surface porosity and profile, over/under application etc - which should always be considered when calculating the practical rate.

The T.S.R is calculated thus: Volume Solids x10 / Dry Film Thickness (microns).

D.F.T = Dry Film Thickness. The theoretical build (measured in microns) of the paint film once dry, following evaporation of the solvent.

The D.F.T is calculated thus : Wet Film Thickness (microns) x Volume Solids / 100.

W.F.T = Wet Film Thickness. The theoretical build (measured in microns) of the paint film as applied, before evaporation of the solvent.

The W.F.T is calculated thus : Dry Film Thickness (microns) x 100 / Volume Solids.

Volume Solids. The percentage of the coating which will remain to form the dry film. For example, if a coating has 60% volume solids, 40% is the amount which is lost as the paint dries. Consequently, the volume solids has a direct bearing on the theoretical spreading rate; the higher the volume solids, the higher the spreading rate.
Increasingly, volume solids is becoming more important as the trend moves to "environmentally friendly" , or "compliant" coatings. This is because as the volume solids figure is increased, logically the amount of emmited solvent is reduced. An EPA compliant coating will typically have a volume solids figure of at least 55%. For more information on the EPA (Environmental Protection Act), go to our links page.

Thinner / Clean-up. The required solvent for thinning, or for cleaning of equipment after use. Note some items may require more than one type of thinner depending upon the method of application. The thinning ratio can also vary depending on the product and/or the surface to be applied. Refer to individual technical data sheets for more detailed information.