- MIG welding (GMAW)
- Gas Metal Arc Welding — feeds a wire electrode under a shielding gas. The workhorse process for steel collision panels.
- Body filler
- A polyester putty applied in thin layers over prepared metal to fill minor imperfections, then sanded smooth. A finishing material, not structural.
- Featheredging
- Sanding the edges of damaged paint and filler so the layers taper gradually into the surface, leaving a smooth, invisible transition.
- Corrosion protection
- The primers, sealers, and coatings that must be restored to bare repaired metal — repairs strip the factory rust protection.
- Stitch weld
- A series of short welds with cooling gaps between them, used to limit heat distortion when welding thin sheet panels.
- Adhesive (panel) bonding
- Joining panels with a two-part structural adhesive — no heat, so no weld distortion, and it seals the joint against corrosion.
- Direct damage
- Damage where the colliding object actually contacted the vehicle — the obvious crush at the point of impact. Also called primary damage.
- Indirect damage
- Damage away from the contact point, caused as the impact force travels through the structure. Also called secondary damage.
- Kink
- A sharp fold or abrupt change in metal over a short distance; the metal is weakened, so a kinked part usually must be replaced.
- Bend
- A smooth, gradual deformation that transitions evenly from undamaged to damaged metal. A bend can often be straightened.
- Inertia damage
- Damage from loose objects (cargo, spare tire, tools) that keep moving during the crash and strike panels from the inside.
- Substrate
- The base material of a panel — mild steel, high-strength steel, or aluminum. It dictates allowable repair, heat, and welding methods.
- High-strength steel (HSS)
- Steel formulated for strength at lower weight. Advanced HSS often cannot be heated or straightened and must be sectioned or replaced.
- Advanced high-strength steel (AHSS)
- Very high-strength steel used in safety structures; heat destroys its properties, so most AHSS parts are replaced, not repaired.
- OEM repair procedures
- The vehicle maker's published instructions specifying approved methods, materials, weld types, sectioning locations, and replace-only parts.
- Damage analysis
- Inspecting a vehicle to classify direct, indirect, and inertia damage and trace the path and direction of the impact force.
- Direction of impact
- The line the collision force traveled; found by locating direct contact and tracing how damage radiates through the structure.
- Repair plan
- The documented sequence of operations, parts, and methods for a repair, based on damage analysis and OEM procedures.
- Repair vs. replace decision
- Choosing whether to fix a panel or install a new one, based on substrate, damage severity (kink vs. bend), and OEM guidance.
- Galvanic corrosion
- Corrosion that occurs when dissimilar metals (e.g., aluminum and steel) contact; why aluminum needs isolated tools and a separate area.
- Aluminum work area
- A dedicated, isolated space and tool set for aluminum repair to prevent cross-contamination and galvanic corrosion.
- Hidden damage
- Indirect damage beyond the visible impact, revealed by cracked seam sealer, broken spot welds, and misaligned gaps.
- Cracked seam sealer
- A tell-tale sign during analysis that collision force traveled through a joint, indicating hidden indirect damage.
- Broken spot welds
- Factory welds split open by impact force — evidence of hidden structural movement found during damage analysis.
- Trim removal & labeling
- Removing moldings, hardware, and trim before repair and documenting each piece's location for accurate reassembly.
- Masking
- Applying tape and paper to protect non-repair areas from overspray, dust, and damage during repair and refinishing.
- Test fitting
- Fitting a new or adjacent panel before final attachment to verify fit, gaps, and the true extent of hidden damage.
- Panel gaps
- The spacing between adjacent panels; even, consistent gaps are a key target when fitting and adjusting body panels.
- Flushness
- How even adjacent panel surfaces sit relative to one another; correct flushness is part of proper panel alignment.
- Cleaning before inspection
- Washing the damaged area first so dirt and debris don't hide cracks, creases, and the true extent of damage.
- Estimate
- A written assessment of damage, parts, and labor; the B6 test covers estimating in depth, but B3 requires reading damage correctly.
- Pre-repair scan
- A diagnostic scan that documents fault codes before repair so electronic systems can be verified afterward.
- Corrosion (pre-existing)
- Rust found during prep that must be sanded out to bare, sound metal before any repair material is applied.
- Hammer and dolly
- A body hammer worked against a hand-held dolly behind the panel to shape and smooth dents during metal repair.
- Stud welder
- A tool that welds pins/studs to a dented panel so the dent can be pulled out from the outside (no backside access needed).
- Dent pulling
- Drawing a dent back out with a stud welder and slide hammer or pull tabs, used where the backside is inaccessible.
- Shrinking
- Tightening stretched metal back to size and contour so it no longer oil-cans — by heat, a shrinking disc, or cold shrinking.
- Stretched metal
- Metal with more surface area than the panel needs (from impact or over-working) that bulges or flutters until shrunk.
- Oil canning
- A loose, stretched panel area that pops in and out under light pressure; corrected by shrinking the metal.
- Heat shrinking
- Heating a small spot of stretched metal and quickly cooling (quenching) it to shrink it back toward its original shape.
- Cold shrinking
- Working slightly stretched metal back to size without added heat, using controlled hammer-and-dolly technique.
- Shrinking disc
- A friction disc that generates localized heat to shrink stretched metal; cooled to tighten the area.
- Panel replacement
- Installing a new outer body panel when the original is kinked, torn, or too corroded to repair.
- Door skin replacement
- Replacing only the outer skin of a door; the window and lock mechanisms must be checked after installation.
- Quarter panel replacement
- Replacing a welded/bonded rear quarter panel, aligning it carefully with the roof and door for correct gaps.
- Bolt-on panel
- A panel attached with fasteners (fender, hood, deck lid, door) that can be adjusted for gap and flushness.
- Welded-on panel
- A panel joined to the body by welds (quarter panel, rocker); removed by drilling/grinding out the spot welds.
- Door hinge adjustment
- The primary way to correct door alignment; hinges set up/down, in/out, and fore/aft position in the opening.
- Striker adjustment
- Adjusting the latch striker so the door latches cleanly — done after the door is positioned with the hinges.
- Rivet bonding
- Joining panels with structural adhesive plus rivets, used per OEM to preserve high-strength steel without high heat.
- Sectioning
- Replacing part of a panel by cutting at OEM-approved locations and joining new metal, rather than full replacement.
- Aluminum panel repair
- Aluminum relaxes with heat for easier shaping but needs isolated tools; it is welded or bonded differently than steel.
- Rust inhibitor
- A coating applied to repaired metal to prevent corrosion where protective coatings were removed during repair.
- Crowned panel
- A curved panel surface; metalwork must restore the original crown/contour for a correct fit and finish.
- Pull (frame/panel)
- Applying tension to draw damaged metal back toward its original position before final shaping.
- Clamp/fixture
- Tooling that holds a replacement panel in position for accurate test fitting and welding or bonding.
- Spot weld cutter
- A drill-type cutter used to remove factory spot welds when separating a welded-on panel.
- Backside access
- Whether you can reach behind a panel; determines if you use a hammer-and-dolly or must pull from the front with a stud welder.
- Crush zone
- An area engineered to deform and absorb energy; OEM procedures govern whether it is repaired or replaced.
- Heat distortion
- Warping of thin or high-strength panels caused by welding heat; minimized by stitch welding or by bonding instead.
- Mating flange
- The overlapping edge where two panels join; cleaned and straightened before fitting a replacement.
- Metal finishing
- Working a panel back to its true contour with hammers, dollies, picks, and files so little or no filler is needed.
- Body file
- A flat file (or 'cheese grater') used to check panel flatness and shave high spots from curing filler, exposing lows.
- Pick and file
- Raising minor low spots with a pick hammer and filing the highs to smooth small surface imperfections in metal.
- Planishing
- Hammering to flatten and smooth a welded or worked area, refining the surface finish after welding.
- Guide coat
- A thin contrasting layer misted over filler/primer that disappears from highs and stays in lows, mapping imperfections.
- Block sanding
- Sanding with a flat block (not fingers) to level filler and primer into a truly flat, wave-free surface.
- Polyester body filler
- Common, easy-to-sand filler for non-structural repairs; applied in thin layers over clean, prepared metal.
- Metal glaze
- A fine finishing filler applied in a thin layer over minor imperfections for a smooth surface before priming.
- Thin layers
- The correct way to apply filler — multiple thin coats adhere and cure properly; one thick layer shrinks and cracks.
- Surface preparation (filler)
- Cleaning, degreasing, and sanding metal so body filler bonds properly and resists future delamination.
- Degreasing
- Removing oils and contaminants with a cleaner so paint, filler, and adhesives adhere correctly.
- Primer over filler
- A primer-surfacer applied over cured, sanded filler to seal it, level minor flaws, and promote paint adhesion.
- Self-etching primer
- A primer that lightly etches bare metal for strong adhesion and corrosion resistance on small repair areas.
- Epoxy primer
- A durable corrosion-protective primer for bare metal, often the first coating on a repaired panel.
- High build primer
- A thick primer-surfacer that fills fine sand scratches and minor lows, then is block-sanded flat.
- Feather edge
- The tapered, sanded edge of paint layers that blends a repair smoothly into the surrounding original finish.
- Low spot
- An area below the panel's true contour, filled or raised so the finished surface is flat and even.
- High spot
- An area above the panel's true contour, knocked or filed down during metal finishing.
- Sanding grits
- Progressively finer abrasives used to shape, smooth, and prepare filler and paint for refinishing.
- Curing (filler)
- The chemical hardening of catalyzed filler; file or sand at the right stage for the cleanest cut and best finish.
- Hardener (catalyst)
- The cream activator mixed into body filler in the correct ratio to make it cure; too much or too little causes problems.
- Air bubbles in filler
- Voids from improper mixing or thick application that create pinholes; avoided by mixing well and applying thin.
- Body hammer
- A finishing hammer with crowned and/or flat faces used with a dolly to shape and smooth panel metal.
- Dolly
- A shaped steel hand block held behind a panel as a backing for hammer work during metal finishing.
- Urethane adhesive
- The high-strength adhesive that bonds modern windshields, applied as a continuous triangular bead; adds body strength.
- Continuous triangular bead
- The recommended urethane bead shape for setting a windshield — seals evenly all the way around the opening.
- Pinch weld
- The flanged metal edge around a glass opening that the urethane bonds to; bare metal here must be primed.
- Glass primer
- Primer applied to the pinch weld (and sometimes the glass frit) to prevent corrosion and promote urethane adhesion.
- Safe drive-away time
- The minimum cure time before a urethane-set windshield can safely support the vehicle in a crash; must be observed.
- Bonded (stationary) glass
- Glass adhered to the body with urethane (windshield, backglass) rather than mechanically fastened.
- Movable glass
- Door and quarter glass that slides; adjusted parallel to the frame so it runs smoothly and seals correctly.
- Tempered glass
- Heat-treated glass (side/rear windows) that shatters into small pieces; handle carefully to avoid sudden impacts.
- Laminated glass
- Two glass layers bonded to a plastic interlayer (windshield) that holds the glass together when cracked.
- Water leak test
- Spraying water around a newly set glass to confirm there are no leaks before returning the vehicle.
- Window regulator
- The mechanism (cable or scissor) that raises and lowers door glass, driven by a motor or crank.
- Power window motor
- The electric motor that drives the regulator; checked after the fuse/breaker when a window won't move.
- Fuse and circuit breaker
- The first electrical items to check when a power window is dead — the simplest, most common cause.
- Rear defogger grid
- Conductive grid lines on the backglass; breaks are found with a multimeter checking for continuity.
- Multimeter
- A meter used to check continuity and voltage — e.g., locating a break in a rear-defogger grid line.
- Cut-resistant gloves
- PPE worn when handling automotive glass to protect hands from cuts during removal and installation.
- Side airbag precaution
- Disconnect the battery before opening a door with a side airbag to prevent accidental deployment.
- Door panel reinstallation
- Refitting interior trim after glass work, reconnecting every electrical connector for proper function.
- Weatherstripping
- The rubber seal around glass and doors that blocks water and wind noise; window alignment affects its seal.
- Pit filler resin
- A resin used in glass chip repair to smooth the final repaired surface to a clear, level finish.
- Glass adjustment
- Aligning movable glass parallel to the door frame so it seals against the weatherstrip and operates smoothly.
- Shielding gas (75/25)
- 75% argon / 25% CO2 — the common MIG gas for steel collision panels, balancing penetration, arc stability, and low spatter.
- Resistance spot welding (STRSW)
- Squeeze-type resistance spot welding that reproduces factory spot welds by passing current through clamped metal.
- Plug weld
- A weld filling a pre-drilled hole in the top panel to fuse it to the panel beneath, simulating a spot weld with a MIG gun.
- Plasma cutter
- A tool that cuts high-strength and other steels precisely with minimal heat distortion, using an ionized gas arc.
- Oxy-acetylene torch
- A flame torch for cutting/heating; primary hazard is fire and explosion from the highly flammable gases.
- TIG welding
- Gas Tungsten Arc Welding — precise heat control and superior quality, often used for aluminum collision repair.
- MIG brazing
- Lower-heat joining with a silicon-bronze wire, used per OEM to preserve high-strength steel properties.
- Spot weld removal
- Drilling or grinding out factory spot welds to separate a welded-on panel without damaging the structure.
- Weld penetration
- How deeply a weld fuses into the base metal; controlled by gas, voltage, wire speed, and technique.
- Weld spatter
- Bits of molten metal thrown from a weld; reduced with proper gas blend, settings, and clean metal.
- Burn-through
- Melting a hole in thin sheet from too much heat; prevented by correct settings and stitch welding.
- Welding ventilation
- Removing harmful fumes when welding, especially in confined spaces, to keep the air safe to breathe.
- Fire prevention (welding)
- Removing flammable materials and having an extinguisher ready, since sparks and heat easily ignite them.
- Weld test coupon
- A practice weld on scrap of the same metal/thickness, destructively tested to verify settings before the real weld.
- Reciprocating saw
- A cutting tool for body metal; use the appropriate blade for the metal type for clean, efficient cuts.
- Air chisel
- A pneumatic chisel used to cut or separate body metal during panel removal where appropriate.
- Seam sealer
- A flexible sealant over welded/bonded seams that blocks water and air, prevents corrosion, and restores appearance.
- Weld-through primer
- A conductive primer applied between mating flanges before welding to protect the joint from corrosion.
- Cavity wax
- An anti-corrosion coating sprayed into enclosed/boxed sections that can't be primed directly.
- Anti-corrosion coating
- Material applied to repaired and enclosed areas to restore the rust protection removed during the repair.
- Welding PPE
- Auto-darkening helmet, gloves, and flame-resistant clothing that protect from UV light, heat, and spatter.
- Welding distortion control
- Techniques (stitch welding, clamping, heat sinks) that limit warping of thin panels during welding.
- Squeeze-type resistance
- The clamping force in STRSW; correct pressure is critical for proper metal fusion and weld strength.
- Destructive weld test
- Peeling or twisting a test weld apart to confirm it tore the base metal (a sound weld) rather than the weld itself.
- Grinding (weld cleanup)
- Smoothing a finished weld flush; minimize removal so the weld isn't weakened, then re-protect the bare metal.
- Welding cable/ground
- A clean, solid ground connection near the weld for consistent current flow and weld quality.
- Thermoplastic
- A plastic that softens with heat and can be reshaped or welded, re-hardening on cooling (e.g., TPO, polypropylene).
- Thermoset plastic
- A permanently cured plastic that chars rather than melts when heated; repaired with adhesives, not welding.
- Plastic identification
- Determining the plastic type — by the molded-in ISO code and a hidden heat/grind test — to pick the right repair.
- ISO code (plastic)
- The molded-in marking (TPO, PP, PUR, ABS) on a part's backside identifying its composition and repair method.
- Hot-air plastic welder
- A tool that melts and fuses thermoplastic with hot air and filler rod to repair cracks in bumpers and trim.
- Two-part plastic adhesive
- An epoxy/urethane adhesive used to repair thermoset (and many thermoplastic) parts that can't be heat-welded.
- V-grooving
- Grinding a V-shaped channel along both sides of a plastic crack to increase surface area for a stronger adhesive bond.
- Reinforcing mesh
- Fiberglass or metal mesh embedded on the backside of a plastic repair to add structural strength.
- Flexible filler
- An elastomeric filler that flexes with a bumper or trim part so the repair won't crack as the panel moves.
- Flexible primer surfacer
- A primer formulated to bend with flexible plastic so the finish doesn't crack; some need a flex additive.
- Plastic adhesion promoter
- A product applied to certain plastics (like raw TPO) so paint and adhesives will bond to the low-energy surface.
- Plastic cleaner
- A solvent made for plastics used before repair to remove contaminants without damaging the substrate.
- Low-heat setting
- Using minimal heat on plastic repair to avoid warping or distorting the part.
- TPO (thermoplastic olefin)
- A common bumper-cover thermoplastic; weldable with heat and usually needs an adhesion promoter for refinishing.
- Polypropylene (PP)
- A widely used thermoplastic in bumpers and trim; repaired by plastic welding or compatible adhesives.
- Polyurethane (PUR)
- A flexible plastic often found in bumper covers; commonly repaired with two-part flexible adhesives.
- ABS plastic
- A rigid thermoplastic used in interior and some exterior parts; repairable by welding or solvent/adhesive methods.
- Bumper cover repair
- Restoring a cracked or torn plastic bumper cover with welding or adhesive, then a flexible filler and primer.
- Over-sanding (plastic)
- Removing too much material from a plastic part, thinning and weakening it; avoided to preserve strength.
- Heat gun (plastic)
- Used to soften a flexible plastic part for reshaping back toward its original form before repair.
- Crack repair (plastic)
- Cleaning, V-grooving, reinforcing, and filling a plastic crack so the repair is strong and flexible.
- Substrate flexibility match
- Matching the flexibility of fillers and primers to the plastic part so the repair bends without cracking.
- Inner structure inspection
- Checking core supports, rails, and floor seams for cracked sealer and broken welds to find hidden indirect damage.
- Vehicle history / records
- Service and collision history reviewed during analysis to distinguish new damage from prior repairs.
- Primary vs. secondary damage
- Another name for direct vs. indirect damage — primary at the contact point, secondary as force travels onward.
- Substrate identification test
- Using a magnet, markings, and references to tell steel from aluminum before choosing a repair method.
- Restricted repair zone
- An area an OEM forbids cutting/welding/heating; identified from the repair procedure before work begins.
- Mock-up / dry fit
- Loosely assembling parts to confirm alignment and reveal hidden damage before committing to the repair.
- Corrosion-prone area
- Seams, flanges, and enclosed sections needing extra protection because moisture collects and rust starts there.
- Slide hammer
- A weighted tool that pulls dents outward when attached to studs, pins, or hooks welded/screwed to the metal.
- Pull tabs / glue pulling
- Adhesive tabs bonded to a panel and pulled to remove dents without drilling or welding (paintless-style).
- Panel alignment
- Setting a panel for even gaps and flush surfaces with its neighbors as the final fit step.
- Sectioning joint
- An OEM-approved location and method (butt, lap, sleeve) for joining new metal during a partial panel replacement.
- Replacement panel selection
- Choosing a panel that matches the vehicle make, model, and substrate for correct fit and function.
- Pinholes
- Tiny voids in cured filler from air bubbles; filled with glaze and re-sanded before priming.
- Sand scratch swelling
- Topcoat sinking into coarse scratches, showing them later; avoided with proper grit progression and sealing.
- Bare metal protection
- Priming exposed metal promptly after metalwork so it doesn't flash-rust before refinishing.
- Frit band
- The black ceramic border on bonded glass that hides and protects the urethane from UV; primed as specified.
- Cold knife / wire-out tool
- Tools used to cut the old urethane and remove a bonded windshield without damaging the pinch weld.
- Short bead / drive-away failure
- An incomplete urethane bead or too-short cure that can let the windshield separate in a crash — a safety defect.
- Joule / heat input
- The welding energy delivered; too much warps and weakens, too little under-fuses — set for the metal and thickness.
- Spot weld count
- Reproducing at least the factory number of welds (often plus extra) per OEM when re-attaching a panel.
- Welding helmet shade
- The darkening level of the lens; too light risks eye damage (arc flash), so use the correct auto-darkening shade.
- Melt flow / weldability
- How a thermoplastic flows when heated, indicating whether and how it can be plastic-welded.
- Backside reinforcement
- Applying adhesive and mesh to the rear of a plastic crack to restore strength before finishing the front.
- Two-part adhesive mixing
- Combining base and hardener in the correct ratio (often via a static mixer tip) for a proper structural bond.
- Squeeze-out (adhesive)
- Excess adhesive pushed from a bonded joint; confirms full coverage and is tooled before it cures.
- Heat-affected zone (HAZ)
- The metal beside a weld whose properties change from heat; minimized on high-strength steel by low-heat joining.
- Weld porosity
- Gas pockets in a weld from contamination or poor shielding that weaken it; cleaned metal and good gas prevent it.
- Coarse-grit sanding (plastic)
- Removing deep scratches from hard plastic with coarse grit, then finer grits to smooth before refinishing.
- Guide-coat for plastic
- A contrast coat used when block-sanding a plastic repair to find highs and lows just as on metal.
- Damage report review
- Reading the estimate/damage report during preparation to plan operations and confirm needed parts.
- Trim clip / fastener reuse
- Replacing broken clips with new ones and reusing good fasteners so reinstalled trim fits tightly.
- Quarter-to-roof joint
- A critical alignment when replacing a quarter panel; bonded or welded per OEM with correct gaps.
- Dust extraction
- Vacuum sanding that captures dust for a cleaner repair, better visibility, and a healthier shop.
- Backglass (rear window)
- Bonded or movable rear glass; bonded units are set with urethane like a windshield.
- Sunroof/movable glass seal
- Adjusting movable roof glass so it seals and drains correctly without leaks or wind noise.
- Welding clamps
- Intra-grip and locking clamps that hold panels tightly aligned for accurate, distortion-free welding.
- Plastic weld rod
- Filler rod matched to the base plastic, melted into a V-groove to fuse and rebuild a thermoplastic repair.
- Spot weld drill bit
- A special bit/cutter sized to remove a factory spot weld cleanly without enlarging the lower-panel hole.
- Adhesive open time
- The window after mixing structural adhesive during which panels must be joined before it starts to cure.
- Weld-through coating limits
- Keeping weld-through primer thin at the weld so it conducts; excess causes porosity in the weld.
- Argon (aluminum gas)
- Pure argon shielding used for welding aluminum, which needs cleaner, more controlled shielding than steel.
- Solvent test (plastic)
- Touching a hidden spot with solvent to help identify a plastic by whether it softens or is unaffected.
- Corrosion at repair edge
- Rust that can creep from a poorly protected repair seam; prevented by full priming and sealing.
- Damage to adjacent panels
- Checking neighboring panels for indirect damage and fit before finalizing a single-panel repair plan.
- Glass set tools (suction cups)
- Suction-cup handles used to position and set heavy bonded glass accurately onto the urethane bead.
- Refinish prep (final)
- Cleaning, masking, and priming a completed repair so it's ready for color and clearcoat.