Red Seal Painter & Decorator key terms

The thickness of a coating measured immediately after application while still wet. Painters use a comb gauge to check it and confirm the dry film will fall within the manufacturer's specified range.

The thickness of a cured coating film, measured with a magnetic or eddy-current gauge on metal or a destructive test on other substrates. It determines coverage, durability, and whether the specified system was applied.

The percentage of a coating's liquid volume that remains as dry film after the solvents evaporate. It lets you calculate theoretical coverage and compare products at equal film thickness.

The area one litre or gallon of coating covers at a stated film thickness, calculated from volume solids. It is a laboratory figure; practical coverage is lower because of loss to texture, overspray, and equipment.

Units for film thickness. One mil equals one thousandth of an inch (25.4 microns). Specifications may be written in either, so painters convert between them when checking gauges and product data sheets.

A systematic list of every surface and quantity to be coated, measured from drawings or on site. It feeds the estimate for labour, materials, and access equipment.

The area a product covers per unit volume at a given film thickness, usually stated on the label in square metres per litre. It is the field figure used to order material.

The microscopic roughness of a substrate created by abrasion or blast cleaning. The correct anchor pattern helps a coating bond mechanically; too smooth causes slipping, too rough wastes material and can leave thin peaks.

The specific roughness pattern produced by blasting media on steel or concrete, described by depth and angularity. It is verified against the specification before priming because adhesion depends on it.

Published industry designations such as SP 1 (solvent cleaning), SP 2 (hand tool), SP 3 (power tool), SP 6 (commercial blast), and SP 10 (near-white blast) that specify how clean a surface must be before coating.

Propelling sand, grit, or other media at a surface under pressure to remove rust, mill scale, old coatings, and to create a profile. It requires supplied-air respiratory protection and full containment.

Working through progressively finer abrasive grits so each scratch is removed by the next grit. Skipping grits leaves pigtails and swirl marks that show through glossy finishes.

A resin-impregnated cloth used to wipe dust from a prepared surface just before coating. It picks up fine particles a brush cannot remove, preventing nibs in the finish.

The temperature at which air becomes saturated and moisture condenses. Paint must not be applied when the surface is within about 3 °C of dew point, or when humidity and temperature fall outside the product's data sheet.

The amount of water vapour in air expressed as a percentage of saturation at that temperature. It controls drying, curing, and adhesion, and most products state an acceptable range on the label.

The percentage of water held in masonry, plaster, or wood. Coatings applied over damp substrates blister or flake, so readings are taken with a moisture meter and compared to the manufacturer's limit.

The period during which a second coat may be applied without surface preparation. Too early causes solvent trapping or lifting; too late requires abrading because the film has fully hardened.

The usable working time of a catalysed or two-component product after mixing. Material left beyond pot life thickens and must be discarded, not thinned, because its cure chemistry is spent.

The reactive component mixed into a two-pack coating to start cross-linking. Correct ratio and induction time are critical; wrong ratios leave a soft film or shorten pot life dramatically.

A two-component coating offering hard, chemical-resistant films with strong adhesion. It chalks in sunlight, so it is used as a primer or intermediate coat and topcoated with polyurethane for exterior exposure.

A coating, often two-component, that cures to a tough, glossy, UV-stable film. It is used as a clear or pigmented topcoat over epoxy and on floors and trim where abrasion resistance matters.

The first coat, formulated to bond to the substrate and provide adhesion, corrosion resistance, or a uniform base for following coats. Primer choice depends on substrate, such as zinc phosphate for steel or alkali-resistant for masonry.

A thin, penetrating or film-forming coat that reduces absorption of the topcoat into porous surfaces. It prevents flashing, patchiness, and excessive material use on drywall, masonry, and wood.

A pigmented coat applied over primer to build film, hide the substrate colour, and create a smooth surface for the finish. It is sanded lightly before topcoating.

The final coat that provides the specified colour, sheen, and performance. It must be applied at the correct wet film thickness and under suitable conditions to achieve uniform appearance.

The degree of light reflectance from a dried film, graded from flat through matt, eggshell, satin, semi-gloss to high gloss. Higher sheen shows surface defects and is easier to clean.

Uneven gloss or colour patches in a dried coat caused by poor application, porous substrates, or lapping over partly dried paint. Applying a sealer and maintaining a wet edge prevent it.

The boundary of a freshly applied coat that has not yet dried. Keeping it wet allows the next brush or roller load to blend in; losing it leaves lap marks.

Brushing a narrow band of coating along edges, corners, and trim before rolling the field. It creates a clean line and lets the roller work without touching adjacent surfaces.

Visible lines where a wet coat overlaps a partially dried one, leaving a thicker, glossier band. They result from poor wet-edge control, hot conditions, or rolling too large an area.

Wrinkling or detachment of a new coat caused by its solvents softening an incompatible or insufficiently cured underlying film. Testing for compatibility and allowing full cure prevent it.

A field check of how well a coating bonds to its substrate, done by cross-hatch or pull-off methods. Failure reveals poor preparation, contamination, or incompatible products.

Dome-shaped raised areas in a film caused by moisture, solvent, or air trapped beneath it. It often follows coating damp substrates or applying in direct sun.

A white, powdery salt deposit on masonry as water migrates through and evaporates. It signals moisture problems and must be removed and the source corrected before coating.

Degradation of a coating, usually on fresh masonry or concrete, caused by alkaline salts attacking the film. It shows as discolouration or saponification and is prevented with alkali-resistant primers and adequate curing.

Inhalation of respirable crystalline silica dust from blasting, sanding, or cutting concrete, which can cause silicosis. Controls include wet methods, dust extraction, containment, and fit-tested respirators.

A formal check that a tight-fitting respirator seals to the wearer's face, done qualitatively or quantitatively. It is required before use, after facial changes, and annually under most regulations.

Capturing dust at the source with a vacuum or shroud attached to sanders and saws. It protects workers and occupants and reduces cleanup and contamination of wet coatings.

Canada's Workplace Hazardous Materials Information System, requiring supplier labels, safety data sheets, and worker training for hazardous products. Painters rely on it for solvents, isocyanates, and silica-containing materials.

A standardized document listing a product's hazards, ingredients, first aid, handling, storage, and disposal. It must be accessible to workers and is the first reference before using an unfamiliar coating.

The mass of volatile organic compounds released per litre of product as it dries. Regulations cap VOC levels, and painters select compliant products while managing ventilation and odour.

A coating in which water is the main carrier, with low VOC and odour. It dries by coalescence, cleans up with water, and needs care in cold or humid conditions.

A coating carried in organic solvents, offering good flow, penetration, and hardness. It requires solvent-resistant gloves, ventilation, fire precautions, and longer recoat times.

The process by which waterborne resin particles merge into a continuous film as water evaporates. It needs adequate temperature and usually a coalescing solvent to avoid a powdery, poorly bonded film.

Low-tack masking tape used to protect trim and glass and to produce sharp lines. It should be removed while the coating is still wet or scored first if fully cured.

Covering and protecting surfaces not being coated, using tape, film, paper, or drop cloths. Careful masking prevents overspray damage and reduces cleanup time.

Airborne paint particles that settle on unintended surfaces beyond the spray pattern. It is controlled by adjusting the gun, using the right tip, and masking or shielding the area.

The proportion of coating sprayed that actually lands on the target. Airless and HVLP systems achieve higher efficiency than conventional air spray, reducing material use and overspray.

A pump that forces coating at high pressure through a small tip, atomizing it without air. Tip size and pressure must match the product; it delivers high output but demands careful tip selection and safety.

The orifice diameter and spray width of an airless tip, marked in thousandths of an inch and inches of fan. They are matched to coating viscosity and surface size for even coverage.

An adhesive chosen to match the wallcovering type, such as clear, vinyl-to-vinyl, or heavy-duty. Correct paste and proper soaking time control shrinkage, seams, and adhesion.

Folding pasted wallcovering strips accordion-style so the paste soaks in and the strip stays manageable. It equalizes moisture, prevents shrinkage at seams, and follows the manufacturer's soak time.

A small hard roller run along wallcovering seams to press the edges firmly to the wall. It improves adhesion and flattens the seam without stretching the material.

A decorative finish of lime-based plaster applied in thin, burnished layers to create depth and a marble-like sheen. It requires polished trowel technique and controlled drying between coats.

A decorative technique that imitates natural materials such as marble, wood, or stone using glazes, tools, and layered application. It relies on sample boards and consistent technique for approval.

A translucent coating applied over a base coat and manipulated with brushes, rags, or sponges to create texture and depth. Its open time controls how long it can be worked.

A physical panel showing the proposed finish, colour, and sheen, approved by the client before production work begins. It becomes the reference standard for the completed job.

A written list of incomplete or defective items identified at inspection and corrected before final acceptance and payment. It documents agreed remedies and closeout.

A written authorization for work outside the original scope, stating the added cost and time. It protects both parties and should be signed before the extra work proceeds.

An instrument that measures light reflected from a surface at a set angle to quantify sheen in gloss units. It is used to verify a finish against a specification or approved sample.