After Tack
Where a paint film dries up to a certain level but then remains tacky. This generally occurs when exterior varnishes based on a long oil medium is used.
Ageing
The appearance of a paint coating after years of exposure. Defects in the paint film ranging from cracking, crazing, flaking, loss of colour etc. This term may also relate to materials being stored by manufacturers to stabilise before sale.
Aggregate
Various types of fine minerals added in the manufacture of paint to provide a textured finish. The most common minerals are, sand, mica, stone grit of various sizes depending the build and texture required.
Air Drying
Without heat or accelerators. The natural drying of a paint coating when exposed to air. Oxygen in air (oxidation) causes oil paints to set. In water based materials paint dries by evaporation.
Air volume
The amount of air delivered by a compressor and regulated to provide the amount of air required for spraying.