Sags:-
Partial slippage of paint. Thick areas like wide runs. Cause - Heavy thick coats. Gun too close. Badly adjusted gun. See Runs

Sealer:-
A coating whose main function is to reduce gross porosity or to seal in aggressive chemicals. See also primer, size, filler, bonding liquid, undercoat.

Sheen:-
A low gloss with poor distinctness of image; synonymous with gloss measured at an angle of 85 degrees. See also Gloss Assessment

Skinning:-
The formation of an insoluble layer of hardened paint on the top of a coating material in the can. .

Solids content:-
The non-volatile contents; the solid matter remaining after the coating has dried; can be expressed by mass or by volume

Solvent:-
A liquid, usually volatile, which is used to dissolve the binder in a coating, and which reduces the viscosity of the coating, See diluent.

Solvent Popping:-
Small holes in film. Caused by moisture in airlines or solvent trapped under film. See Pin Holing, Cratering, cissing.

Spreading rate:-
The area covered by a litre of paint; expressed in square meters per litre; or square feet per litre. The practical spreading rate is the average area covered by a litre of paint when applied over a normal surface using appropriate means; paint applied at the recommended spreading rate should provide the desired properties (opacity, protection, etc)

Stainer:-
See colourant

Stoving:-
See baking

Stress:-
Resistance to deformation developed within a specimen subjected to an external force

Substrate:-
Any surface to which a coating is applied

Surface dry:-
The state of drying when slight pressure with a finger does not leave an imprint or reveal tackiness; when dry sand applied according to a standard method can be brushed off the coating without sticking to or causing damage to the surface,

Thermoplastic:-
A material which is softened by heat and hardens on cooling. the process of softening and hardening can be repeated,

Thermoset:-
A material which permanently hardens (polymerises) when heated but is not softened by heat.

Thinner:-
A volatile organic liquid used to reduce the viscosity of a coating' usually a blend of different solvents and diluents

Threshold limit:-
Refers to airborne concentrations of substances, and value (TLV threshold limit value) represents the highest concentration of the substance to which a person can be repeatedly exposed, without adverse effect

Tinter:-
See colourant or stainer

Tinting:-
The degree to which a coloured pigment imparts colour strength to a white pigment; usually expressed as a percentage relative to a standard coloured pigment.

Topcoat:-
The last coating applied in a system; provides most of the decorative and protective properties

Touch dry:-
See surface dry

Turpentine:-
A colourless volatile oil distilled from the products of certain pine trees; now generally replaced by mineral spirit or white spirit.

Turpentine substitute:-
Commercial name given to mineral/white spirit.