Glossary - A
Abrading
The use of materials such as glasspaper, wet-or-dry paper, sanding discs, etc. to smooth down a surface prior to painting, or to matt down existing coatings to provide a 'key' for subsequent coats of paint.
Absorbency
The degree to which a surface can soak up a liquid. Some surfaces have varying absorbency, for instance, softwoods vary in grain pattern. One of the requirements of a primer is to produce a non-absorbent surface.
Accelerated weathering
Laboratory or field tests intended to simulate natural outdoor weathering in an intensified or accelerated degree. There is no generally accepted type of laboratory test and expert opinion does not accept that such artificial tests give a true reflection of natural behaviour.
Acrylic
A waterborne latex used in emulsion paint and universally accepted. A synthetic polymer used in high performance latex or water-based paints as the paint's binder acrylic resins enable the coating to last longer and retain its colour.
Acrylic emulsions
These are prepared from acrylic derivatives and normally show very good toughness and adhesion even under wet conditions as well as very good alkali resistance.
Adhesion
The degree of attachment of a paint coating to a surface. Weak adhesion of paint to a surface is a common cause of paint failure. The quality or degree of attachment between a paint coating and the surface or paint beneath it. The ability of dry paint to remain on the surface without blistering, flaking or cracking. Adhesion is probably the single most important property of paint.
Aggregate
A collection of minerals, i.e. fine particles of stone, grit, mica, etc. which provide the textured finish of materials, such as Weather-coat No.1.
Air-drying
A description used for paints that dry solely or mainly during exposure to air at normal temperatures, as distinct from those that require heat-treatment (stoving and force-dried paints) or those that set independently of the surrounding atmosphere (catalysed or 'accelerated' paints).
Aisle
The side portions of a church parallel to the knave. Any passage way divided off by pillars.
Alcove
A recess or niche; sometimes flanked by columns.
Alkali resisting primer
A paint used as a barrier to alkaline substances in the surface which would otherwise attack the paint film. Alkaline surfaces which are continually damp are not effectively sealed for long periods by this method.
Alkyd
A type of 'synthetic' resin that is built up from relatively simple non-resinous components. In practice an alkyd varnish is made by adding such components to a drying oil and treating to produce an 'oil-modified alkyd varnish'. This process is distinct from the traditional method in which a separate gum or resin is 'cooked' with a drying oil to produce a varnish.
Angle iron
Used to describe any cast or rolled steel strip of L section.
Anodising
A method of treating aluminium or light alloy to provide a non-corroding oxide film on the surface of the metal.
Anti-corrosive
A general term for paints used to prevent the corrosion of metal, especially of iron and steel.
Anti-fouling
Compositions used to prevent the growth of barnacles, arine weed and other organisms on ships' bottoms.
Architrave
A carpentry term which describes the moulding surrounding a door or window opening.
Arris
The sharp edge formed by the intersection of two surfaces. This term is commonly used to refer to the edges in a moulding.
Asbestos cement
Usually refers to a type of asbestos sheet, or to casting where the asbestos is bonded together with Portland cement, e.g. asbestos, cement sheet, tiles, rain-water pipes, etc.
Ashlar
Stones which have been cut square are called ashlar as opposed to rough stoned which have been quarried.
Adhesion failure on metal
Adhesion failure on metal substrates, resulting in blistering, flaking/delamination and corrosion, is usually due either to surface contamination or poor surface preparation.
Among the most common types of surface contamination are grease on new galvanised surfaces, which should be cleaned with Dulux Oil and Grease Remover; and wax residue resulting from the use of chemical paint strippers, which can be removed with Dulux Oil and Grease Remover. Dust and general debris should always be vacuumed away before painting.
In terms of surface preparation, the failure to remove millscale from hot rolled mild steel prior to painting can lead to serious problems months or even years later. Similarly, painting over rust can result in the paint film flaking or the rust breaking through the paint film.