Glossary

Abrasion The effect of abrasion on a painted surface is to wear away the paint coating. Acrylic This refers to a synthetic resin which forms an important component in water-based coatings. Adhesion Refers to the ability of a paint film or coating to attach itself to a surface. Aerated Refers to the presence of air bubbles in wet paint. Aerosol Refers to a product that uses compressed gas to spray. These are most commonly found in aersol cans. Alkali A molecular substance that can combine with a proton to produce a new compound such as a soap. Alkyd Is a synthetic resin modified with oil. This forms an important binder component in solvent based paints. Alligatoring Refers to the cracking of a painted surface Asbestos cement Composed basically from fibre and cement and is used for making a wide variety of goods including flat and corrugated sheets, roof tiles and rain water gutters. Bitumin Refers to the black residue from the distillation process of petroleum. Commonly known as asphalt. Blistering These are termed “swollen” areas, which may be visualised as bubbles or lifting of the paint film from the surface beneath. This is an indication of a surface problem, which is a result of localised loss of adhesion. Blooming Refers to a milky appearance on the surface of a paint film and is usually a result of an incorrect balance of thinners in the paint formulation or the rapid evaporation of thinners from the coating. Blushing Refers to a milky appearance on the surface of a paint film usually caused by the condensation of water on the surface. Body This term is often used to describe the thickness or viscosity of a product. Bonding liquid Refers to a low viscosity resin solution, which is used to bind loose particles on a substrate. Building blocks There are various types of building blocks, for example, breeze blocks and concrete blocks. Breeze blocks contain a large amount of furnace clincker, which if saturated with water, will pose paint problems. Concrete blocks are composed of sand, cement and aggregate and may bary in texture. Building boards These are composed of hardboard and softboard. See hardboard and softboard. Catalyst Substance whose presence increases the rate of a chemical reaction, e.g., acid catalyst added to an epoxy resin system to accelerate drying time. Cement plaster See plaster. Cement roof tiles The composition of cement roof tiles is similar to that which is covered in cement plaster except that the tiles are moulded and coloured with an oxide pigment such as red oxide. Chalking This is a phenomenon usually caused as a result of natural elements destroying the binder of the paint so that the pigment comes away as powder on the surface or substrate. All paints are degraded this way and is only considered as a problem when this phenomenon takes place too quickly. Chemical attack This refers to surfaces likely to be contaminated with chemicals such as acids or alkalis after painting. Chipboard Refers to a building board consisting of wood chips and fibres bound with a resin and compressed under high pressure during manufacture. Sometimes such boards are veneered. Chipboard is usually recommended for interior use. Chroma This term is associated with colour and refers to the degree of saturation of a hue. Colorant Refers to colour concentrates (dyes or pigments) that can be added to base paints to create various colours. Colorfast Non-fading in prolonged exposure to sunlight. Concrete Concrete is composed of aggregate, water and cement. Aggregates are usually made up of fine or coarse particles, or from graded particles such as crushed stone sieved to produce the require size. Condensation staining See water staining Copper Refers to a reddish coloured ductile metal. On exposure a green verdigris develops on the surface which protects the copper from further corrosion. Creosoted timber Timber previously dipped or painted with creosote, which is a derivative of tar oil. Creosote like bitumen, will badly discolour any solvent based paint systems applied over it during its early life. and can only be painted with bituminous paint or bituminous aluminium. Damp surfaces This refers to a substrate, which has imbibed water and usually leaves a moist surface. Moisture in walls, ceilings and timber surfaces can cause a variety of problems such as blistering, flaking or even staining of the paint film. Denatured wood When wood is exposed to the weather for long periods the cellular structure of the surface breaks down leaving a surface which is very dry and fibrous. Dirt pick up Refers to the tendency of a coating to attract soiled material which may not be easily removed by simple washing. Dirt retention Refers to the tendency of a coating to retain soiled material. Discolouration Unless one takes precautions, paint applied over bitumen will develop brown stains because the relatively volatile components of tar or bitumen will permeate and migrate through the paint. Pigment and dyes used in some paint formulations are not colour fast and not intended for exterior use. If these are used outside they will fade. Also the alkali and moisture in newly plastered walls or new concrete can react with paint pigments and cause colour changes. Efflorescence Efflorescence refers to fluffy, white salt deposits that are leached out through plaster as water passes through it. Eggshell Refers to the semi - gloss level of a coating. Emulsion paint Coating in which resins are suspended in water, and are brought together with an emulsifying agent, example latex paint. Enamel Paints that dry to a hard, usually glossy finish eg paint used to paint instruments/equipment. Epoxy Very tough, durable and resistant synthetic resin used in specialized coatings. Expanded polystyrene Refers to a lightweight cellular plastic material available in block form and in various tile sizes. Fading See discolouration Ferrous metal Eg iron and steel Fibre glass See glass fibre. Fillers Compositions used to fill surface indentations, cracks etc, in order to produce a smooth level surface prior to painting. Film thickness Refers to the thickness of the dry coating in millimeters. Fineness of grind Refers to the measure of the degree of dispersion. A grind gauge is used for this assessment. Fish eyes Refers to small holes on the surface of a coating, which is usually a result of the presence of oil, grease or silicone contaminant. Flaking surfaces Refers to when the paint film does not adhere to the wall, but “flakes off.” This phenomenon may be a result of a chalking surface or due to a poorly prepared substrate. Flat Generally refers to a matt surface. Formica A proprietary name for decorative laminate sheets and other plastic products. Laminates are widely used for working tops and as a facing for kitchen furniture. Fungal growth See mould and organic growth. Glassfibre Refers to glass which is melted and drawn out into extremely fine fibres, which are then spun or woven into a tough, light material. A combination of glass fibre is them combined with polyester resin and moulded into various shapes. This is now called fibre glass which is widely used in the manufacture of boats. Gloss Refers to how shiny a paint coating. Gloss level Refers to the visual appearance of a surface and depends on the angle at which light is reflected of a coating to the observer. Coatings vary from matt to high gloss. A gloss metre is used to determine scientifically the accurate gloss level of a coating. Gypsum boards Gypsum boards are composed of a layer of gypsum plaster between two sheets of cardboard. Gypsum plaster Gypsum plaster is produced from gypsum rock. Gypsum is basically calcium sulphate and water. Hard dry This refers to the hardness of a paint film on drying. The test here is that by exerting a measurable pressure, no permanent mark or damage is left on the coating. Hardboard Are composed of compressed bonded fibres. These boards are rigid and can only bend to a limited degree. The outer surface is usually plain and smooth. Hiding power This is a measure of the opacity of a coating and is the ability of the coating to obliterate the substrate. Hiding power can be measured using a controlled test method. Insulation boards See building blocks & rhinoboards Knots These are hard cross-grained disfigurements in timber which are formed where shoots on trees are developed into branches. The resin ducts in the timber run parallel to the growth and resin in the knots flow to the surface of the timber. The exposed surface of the knot must be sealed before paint is applied. Lacquer Is a general term used for many fast drying paints which dry purely by solvent evaporation. Paints such as Dulux Duco spray are called lacquers. Laminated boards A general description of a wide range of composite boards such as plywood. Lifting This refers to the rising of a dry paint film on application of the second coat. The paint film actually detaches itself. This phenomenon is visible when for example paint remover is applied to a paint film. Limewash An inexpensive coating which can be applied directly to cement surfaces. Quicklime is the base material and is made from limestone or chalk. To make limewash, the quicklime is slaked with water and while hot, tallow or wool grease is stirred in to form the binding. Mahogany A hard wood which is durable and is use often for high class joinery, shop fitting etc. Mar resistance The ability of a coating to resist damage such as abrasion or impact. Mould and organic growths Moulds, algae, lichens and similar organic growths originate from spores distributed in the atmosphere. These spores settle on any surface and germinate. Further growth depends on the nutrients and moisture being available. On the interior surfaces, damp, poorly ventilated conditions encourage growth. Mould is usually dark brown or black and is sometimes white. Algae and lichens may be black, green, yellow, orange and red. Growth may appear as a surface infection or may be present under painted surfaces and in the substrate, which may grow through the paint coating. No pick up time This term is generally used when discussing road -marking paint. No pick up time is the time lapse between the application of a film of road-marking paint and the exact moment when the paint film is no longer removed, using a standardised measuring instrument. Non-ferrous metals Eg brass, copper, aluminium and lead. Nonvolatile The portion of a coating left after the solvent evaporates. Oak A durable hardwood of importance in structural timbering. Joinery and furniture manufacture. Oak is usually varnished to retain its natural beauty. Opacity The degree of obliteration of a substrate. Orange peel This phenomenon is visualised as a mottled finish (like an orange peel) on the surface of a coating. This may be due to poor paint flow or too thick a coating applied for example. Paint remover A product or chemical that softens old paint or varnish and is easily scraped off. Pin holing Visualised as small holes in the paint film. This may be caused due to moisture in spray lines or solvent entrapment. Plaster Can be concrete or gypsum based. Plaster consists predominantly of cement and sand, and may also contain lime. Depending on its exact composition, new plaster tends to be quite alkaline. Plywood Made by bonding three or more thin layers of wood (plys) with the grain of each sheet laid at right angles to the previous sheet. This gives the finished sheet stability and great strength. Precast concrete Concrete formed into various shapes and profiles prior to erection on site. The wet concrete is poured into suitably shaped moulds and strengthened where necessary with steel mesh and rods. Primer Has several functions. They adhere to the surface and generally dry with a matt finish that gives a key for the next coat of paint. Some protect metal surfaces from corrosion while others seal porous materials, such as softwood and brick, which may otherwise absorb too much of the paint binder. Resinous stains Stains migrating through a paint coating from decomposed resin, normally from the knot. Resin streaks in timber will also bleed through paint coatings. Rubber A material produced by the coagulation and drying of the latec which is contained in some species of trees. Because of its extreme elasticity this material is not suitable for painting with ordinary decorative paints. Rusting surfaces Applies to ferrous metals such as iron and steel which have rusted and require painting. Saponification Saponification refers to alkali attack on the binder a paint and usually takes the form of blisters on the paint film. Blisters form in poor adhesion areas of the film. Very often a yellow oil-like substance is exuded from these blisters. Sealer A coating whose main function is to “seal” in, for example, alkali. Sheen A low- mid gloss coating. Skinning Refers to the formation of an insoluble layer of hardened paint on the top of the “liquid” paint in a can. Staining See bitumen. Stainless steel A corrosion resistant type of steel which does not require protection and is not normally painted. Steel An important constructional material which is basically iron with impurities removed. It combines great strength with hardness and toughness. Surface dry The state of drying when slight pressure is applied with the finger and leaves no imprint on the coating or is not tacky. Surface dry can also be tested using a standardised method. Textured coating Paints which either textured by adding aggregates so as to form a rough surface or thick paint sponged or stippled so as to form a pattern. Thinners A volatile organic liquid used to reduce viscosity of paint and is often a blend of solvents. Titanium dioxide White pigment component of a paint that provides opacity. Top coat This is the coat that will be seen. It provides colour, texture and protection to various surfaces when applied correctly. Touch dry See surface dry. Undercoat A layer of paint that masks surface discolouration adheres well to the previous coating whilst also providing a good key for top coating. Unsound surface Refers to any surface which is in such a condition that normal preparation will not provide a satisfactory surface for painting. Varnished surface Refers to a timber surface painted with an alkyd or polyurethane varnish. Viscosity A measure of a fluid’s ability to resist flow (how thick or thin a paint is.) Water staining Normally occurs on exterior cement surfaces freshly painted with emulsion paint (PVA’s etc.) It is brought about either by condensation or light rain. The water present extracts water-soluble matter from the film and after evaporation leaves behind slightly glossy discoloured streaks on the surface. Whitewash A general term, which can refer to ceiling white or limewash.