Cert III Refinishing key terms

The surface being coated or repaired, such as bare steel, aluminium, plastic, or an existing finish. Identifying the substrate correctly determines which preparation steps and products will bond safely.

All work done to clean, sand, strip, and treat a surface before coating. Proper preparation removes contaminants and creates the mechanical key that lets primers and topcoats adhere reliably.

A number describing the coarseness of sandpaper or discs; lower numbers cut faster and leave deeper scratches, higher numbers smooth finer. Grit sequence must match the stage of repair and the product specification.

A gradual taper sanded at the boundary of a repair so the new material blends invisibly into the surrounding panel. A poor feather edge shows as a visible ring or map under the topcoat.

A thick paste, usually polyester-based, used to rebuild shallow dents and imperfections before priming. It must be applied over a properly keyed, clean surface and sanded smooth.

A first coating applied to a prepared substrate to promote adhesion, fill minor imperfections, and provide a uniform base. Primers are selected to suit the substrate and the topcoat system.

A filling primer sprayed over prepared panels to build film thickness and allow sanding to a smooth, flat surface. It bridges the gap between body repair and the colour coats.

A thin coating applied over primer or existing finishes to give a uniform, sealed base and prevent colour bleed or solvent attack. It also improves topcoat adhesion and colour holdout.

The final colour and clear layers that provide appearance and protection. Topcoat choice, film thickness, and application conditions determine gloss, durability, and colour match.

The pigmented colour layer in a two-stage system that carries the colour and metallic or pearl effect. It dries matte and requires a clearcoat for gloss and weather resistance.

A transparent topcoat applied over basecoat to provide gloss, UV protection, and resistance to chemicals and weathering. Its film build and cure are critical to durability.

A finish containing aluminium particles that reflect light and create sparkle and flop. Application technique, gun distance, and film uniformity strongly affect how the metallic orientation appears.

The process of selecting or adjusting a colour so a repaired area is indistinguishable from adjacent panels. It considers variant colours, application technique, and the effect of the clearcoat.

An adjacent undamaged panel onto which colour is faded so the repair transitions invisibly. Blending hides slight colour differences and panel-to-panel variation.

A surface texture resembling citrus skin, caused by paint that does not flow out before drying. Incorrect viscosity, air pressure, gun distance, or temperature are common causes.

A measure of a liquid's resistance to flow, often expressed in seconds through a flow cup. Correct viscosity ensures proper atomisation and levelling during spraying.

A solvent added to paint to adjust viscosity for spraying and to control drying speed. The correct reducer type must match the product system and ambient conditions.

The usable working time after a two-component product is mixed with its hardener. Exceeding pot life causes poor flow, loss of gloss, and unreliable curing.

A catalyst or activator mixed into a two-pack product in a specified ratio to start the chemical cure. Incorrect ratio or poor mixing causes soft, dull, or non-curing films.

The period required for a coating to reach full hardness and chemical resistance. It depends on product chemistry, film thickness, temperature, and ventilation.

The waiting period between coats that allows solvents to evaporate before the next layer is applied. Too little time traps solvent; too much can hurt intercoat adhesion.

A volatile liquid that dissolves or carries paint resins and evaporates during drying. Solvent choice and evaporation rate affect flow, drying, and finish quality.

A tool that atomises paint and directs it onto the panel using compressed air or another delivery method. Fluid and air settings, pattern, and distance control finish quality.

The breaking of liquid paint into fine droplets by the spray gun. Good atomisation gives an even, smooth film; poor atomisation causes spatter, texture, or uneven colour.

The shape and width of paint delivered by the gun, adjusted to suit the panel and technique. A consistent overlapping pattern prevents stripes and uneven film build.

Airborne paint particles that settle on surfaces outside the intended area. Overspray causes a gritty texture and must be controlled through masking and booth airflow.

Covering and protecting areas that should not receive paint, using tape, paper, or film. Correct masking prevents overspray damage and gives clean edges at trim and glass.

An enclosed, ventilated space for painting that controls airflow, filtration, and contamination. It protects operators and gives a cleaner finish by removing overspray and dust.

Safety gear worn to reduce exposure to hazards, including respirators, gloves, eye protection, and coveralls. Selection must match the chemicals and tasks performed.

A document supplied with a hazardous product that lists its hazards, safe handling, first aid, and emergency measures. It must be available and understood before using the product.

A reactive chemical group found in many two-pack clearcoats and primers, capable of causing serious respiratory sensitisation. Strict ventilation and supplied-air respiratory protection are required.

Particles settling in wet paint and creating specks or nibs in the finish. It is controlled by booth cleanliness, tack cloths, filtered air, and careful handling between coats.

Reshaping damaged metal back to its original contour using hammers, dollies, and related tools. It restores structure and reduces the amount of filler needed.

Joining metal parts by fusion, commonly using MIG processes in vehicle repair. Correct technique restores strength and must be followed by dressing and corrosion protection.

Treatments such as primers, sealers, and cavity waxes that prevent rust forming on repaired steel. Protection must be restored wherever original coatings were removed by repair.

Carefully detaching mouldings, handles, lights, and glass before repair or refinishing. Correct removal and storage prevent damage and allow clean paint edges.

Refitting removed components after painting, including alignment, fasteners, and seals. Careful reassembly avoids scratches and ensures panels and trim sit correctly.

Inspecting the finished repair against standards for colour, gloss, texture, and fit. It confirms the work meets requirements before the vehicle is returned to the customer.