NABTEB Light Vehicle Body Repair key terms

The overalls, boots, gloves, eye shields, ear defenders and respirators a technician wears to reduce injury and health risk. It is the first defence against sparks, dust, paint mist and sharp edges.

A designated person who monitors hot work for smouldering material and stays on guard for a set period after work stops. The role is essential when welding or grinding near fuel, trim or painted surfaces.

A written authorisation naming the work, the area, the precautions and the time limit before welding, cutting or grinding begins. It forces a check of flammables, ventilation and firefighting equipment.

The respiratory and skin sensitisation risk from two-pack paints and primers containing isocyanates. Exposure can cause asthma that persists after contact stops, so supplied-air or approved cartridge respiratory protection and full skin cover are required.

The removal of fumes, dust and overspray from the work area by fans, ducting or booth airflow. Adequate extraction keeps airborne concentrations below exposure limits and prevents combustible vapour build-up.

Injury caused by a moving object hitting a person, or by body parts caught between closing parts such as bonnet hinges, door latches or press tools. Guards, props and safe hand placement reduce the risk.

Rigid stands placed under the chassis or axle to hold a raised vehicle. They must be rated for the load and used on firm level ground, because a jack alone can fail or sink and drop the vehicle.

The uniform clearance between adjacent body panels, such as door to wing or bonnet to wing. Even gaps show correct alignment and are checked with feeler gauges or visual comparison during fitting.

A polished hand-held block of steel held behind a panel while a hammer strikes the outer face. Its shape and mass support the metal, stretch it back into shape and control where the force acts.

A shaped steel hammer with a flat or crowned face used to planish or stretch panel metal. Face shape and weight are chosen to match the damage and the dolly behind the panel.

The paired technique of striking the panel with a hammer while supporting it with a dolly. Correct timing and placement remove dents, restore shape and control stretching rather than thinning the metal further.

Holding the dolly slightly away from the hammer strike so the metal between them is pushed back into shape. It is used to raise low areas and move metal without over-stretching the surrounding panel.

Light, rapid hammer strikes over a dolly to smooth and level metal after rough shaping. It refines the surface and removes small high spots without adding significant stretch.

Reducing the surface area of stretched metal so it returns to shape, done by heat shrinking with a torch or by mechanical shrinking tools. It corrects bulges and oil-canning left after dent removal.

Applying a small red-hot spot with an oxy-acetylene torch and quenching it with a damp cloth or water to contract the metal. The technique removes stretched areas but risks warping if overheated or overused.

Increasing the surface area of panel metal by hammering it outward on a dolly, by pulling, or by heat and hammer work. Controlled stretching raises low areas; uncontrolled stretching creates bulges that need shrinking.

A condition where a panel pops in and out with a clicking sound under light pressure because the metal is stretched and lacks tension. It indicates the panel needs shrinking or replacement rather than filler.

Metal inert gas welding, where a continuous wire electrode is fed into the joint under a shielding gas. It is the common method for joining steel body panels because it is fast and works on thin sheet.

A weld made by filling a hole drilled in the outer panel so it fuses to the panel beneath. It is widely used to attach replacement panels at factory spot-weld positions where access is one-sided.

A series of short overlapping welds with gaps between them, used to control heat input on thin panels. The gaps are filled in stages to limit distortion and allow cooling.

Warping, buckling or shrinking of metal caused by uneven heating and cooling during welding. It is controlled by stitch welding, clamping, heat sinks and allowing the panel to cool between passes.

A weld made by passing current and pressure through overlapping sheets at a single point, typical of factory body assembly. It is reproduced on repair with a spot welder or a plug weld.

A specialised drill bit that cuts through the outer sheet around a spot weld without destroying the panel underneath. It allows a welded panel to be separated cleanly for replacement.

Joining metal by melting a filler with a lower melting point than the workpieces, without melting the base metal. It is used on some panel joints and for building up worn areas where heat must be limited.

Adjusting hinges, latches, shims and mounting points so a replacement panel sits with correct gaps and flushness. It is checked before final tightening and before any refinishing begins.

Placing thin metal or plastic spacers under a hinge or mounting point to raise or shift a panel. Shims correct gap and flushness without bending the panel itself.

The process of freeing a damaged panel by drilling spot welds, cutting seams, unbolting fixings and releasing adhesives. Careful labelling and support prevent damage to adjacent panels and wiring.

A paste of resin and filler powder applied to a prepared panel to level small imperfections before painting. It must be applied thinly over sound, abraded metal and never used to bridge structural gaps.

A flexible plastic or rubber blade used to apply and shape body filler. Firm pressure at a shallow angle forces filler into the repair and leaves a smooth, thin layer.

A light mist of contrasting paint or powder dusted over primer or filler so low spots and sanding scratches show during blocking. It is sanded away to reveal the true surface level.

A coating applied over prepared metal and filler to build film thickness, improve adhesion and provide a sandable layer. It is blocked flat before the topcoat is applied.

A thin, mildly acidic primer that promotes adhesion to bare steel and aluminium and gives some corrosion protection. It is applied in a light coat and must not be sanded off completely before the next layer.

Steel or aluminium panel surface with no paint, primer or coating remaining. It must be cleaned and protected quickly because it rusts or oxidises once exposed to air and moisture.

An enclosed, ventilated and filtered chamber where refinishing is done. It controls dust, temperature and airflow, protects the finish and keeps solvent and isocyanate vapours away from the workshop.

A paint supplied as two components, a base and a hardener, that react chemically after mixing. It gives a durable finish but has a limited pot life and carries isocyanate hazards.

Selecting or mixing a paint so it matches the existing vehicle finish under the correct light. It uses the vehicle paint code, variant chips and spray-out cards, with blending into adjacent panels where needed.

Fading a new paint edge into the surrounding original finish so no colour or texture difference is visible. It is used when an exact panel-to-panel match is unlikely or the panel is only partly refinished.

Corrosion that occurs when two different metals, such as steel and aluminium, are joined and moisture forms an electrical circuit between them. The less noble metal corrodes faster, so isolation is required at mixed-metal joints.

A flexible sealant applied to panel joints, overlaps and hem flanges to keep water out and reduce corrosion and noise. It must be applied to clean metal and painted over where the factory finish requires it.

A glazing unit made of two glass layers bonded to a plastic interlayer that holds fragments in place when broken. It is used for windscreens and must be cut out and refitted with approved adhesives.

A high-strength flexible adhesive used to bond windscreens and other fixed glass to the body. It provides structural strength in a crash and must be applied at the specified bead size and cure time.

Pulling a damaged chassis or unitary body back to its original dimensions using a rig, chains and hydraulic rams. Measurements are compared with the manufacturer's data throughout the pull.

A reference point or hole on the vehicle body used with a measuring system to check that dimensions are correct. Comparing datum readings before and during repair shows whether the structure has moved.

Damage to load-bearing parts such as chassis rails, pillars, sills or apron panels that affects crash performance. It requires measurement and approved repair methods, not cosmetic filler alone.