Automotive Body Repair & Painting NC II flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

GHS flame pictogram

Symbol on a chemical label indicating a flammable liquid, solid, or gas, such as reducers, thinners, and solvent cleaners used in a body shop.

Safety Data Sheet sections

A 16-section document; Sections 2, 4, 7, and 8 cover hazards, first aid, handling and storage, and exposure controls for shop chemicals.

Lockout tagout purpose

Procedure that isolates, locks, and tags an energy source before servicing spray booths, compressors, or pulling equipment, preventing accidental startup or release.

Isocyanate sensitization risk

Repeated exposure to urethane hardeners can cause occupational asthma; supplied-air or appropriate cartridge respirators and strict exposure limits are required.

Vernier caliper least count

On a metric caliper with 50 vernier divisions over 49 main divisions, the least count is 0.02 mm, so the reading is main scale plus vernier line times 0.02 mm.

Micrometer reading method

Reading equals the barrel main-scale value plus the thimble division multiplied by the least count, typically 0.01 mm on a 0-25 mm metric micrometer.

Torque wrench storage rule

Store the wrench at its lowest scale setting to preserve spring calibration; accuracy is only valid within the stated percentage of full scale.

Stud welder ground clamp

The ground must contact clean bare metal on the same panel being pulled so the capacitive discharge current flows through the weld stud and panel.

Direct versus indirect damage

Direct damage occurs at the impact point; indirect damage is transferred force causing buckles, misaligned gaps, and distortion elsewhere on the structure.

Paint thickness gauge use

Non-destructive meter that measures coating build; readings above roughly 300-400 µm indicate prior refinish or filler needing removal before repair.

On-dolly versus off-dolly

Hammering on the dolly planishes and flattens stretched metal; hammering off the dolly stretches and raises the panel surface.

Heat shrinking steel

Heating a stretched area to dull red, roughly 650-700 °C, then quenching with a damp cloth contracts the metal and removes oil-canning.

Body filler application limit

Filler is applied in thin coats, about 3-6 mm maximum per pass, over a clean, abraded surface, and is never used to bridge structural gaps.

Spot weld removal count

Drill or grind out each factory spot weld and replace the same number at the same locations during panel installation to preserve structural strength.

MIG brazing application

Joining method using a bronze filler at lower heat input, used on high-strength and galvanized steels where fusion welding would weaken the panel.

Sectioning procedure rule

When replacing part of a panel, the cut location, backing insert, and weld type must follow the vehicle manufacturer's published repair procedure.

Squeeze-type spot welder

Resistance welding equipment that clamps and fuses overlapping steel panels with current and pressure, the OEM-preferred method for structural steel joints.

Galvanic corrosion prevention

Use dedicated aluminum tools and rivets on aluminum panels; mixing steel fasteners or contaminated abrasives with aluminum causes galvanic corrosion.

Abrasive grit progression

Sequence of abrasive grades: 80-180 for stripping and shaping, 240-400 for primer, and 600-800 for blending and pre-clear scuffing.

Wax and grease remover

Pre-paint solvent cleaner applied with one wet cloth and wiped dry with a second clean cloth before sanding to prevent contamination being driven into the surface.

Mixing ratio by volume

Paint, hardener, and reducer proportions specified on the product data sheet, measured with a graduated mixing cup and stirred before induction time.

Pot life definition

The usable working time after a catalyzed product is mixed; material must be used within this time and never extended by adding fresh product.

Reducer speed selection

Fast reducer suits cool shop conditions while slow reducer suits hot conditions, controlling flow, leveling, and solvent pop during application.

Epoxy primer purpose

Two-component primer applied to bare steel and aluminum as a corrosion barrier and adhesion promoter before filler or topcoat systems.

Spray gun fluid tip sizes

Common setup is 1.3-1.4 mm for basecoat and clearcoat and 1.6-1.8 mm for primer surfacer and high-build products.

HVLP spray pressure

High-volume low-pressure guns typically operate at about 2-2.5 bar inlet pressure, giving high transfer efficiency and reduced overspray.

Spray distance and overlap

Hold the gun 15-20 cm from the surface with 50 percent overlap per pass; too close causes runs, too far causes dry spray.

Orange peel cause

Rough textured finish caused by insufficient atomization, low spray pressure, fast reducer, or inadequate flow, corrected by sanding and polishing.

Fish eye defect cause

Circular craters in the finish caused by silicone or oil contamination, often from compressed air lines or improperly cleaned surfaces.

Blending basecoat technique

Fading the new basecoat into the adjacent panel using a blender or melt-in agent, then clearing to a natural break line for an invisible repair.

Reassembly torque rule

Fasteners are tightened to the manufacturer's torque specification, and torque-to-yield or one-time-use fasteners must be replaced rather than reused.

Solvent waste storage

Solvent-contaminated materials and waste paint go into labeled, closed, grounded metal containers kept separate from general refuse to prevent fire and comply with hazardous waste rules.