Construction Painting NC II flashcards

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

Hierarchy of control

Ranking of hazard controls from most to least effective: elimination, substitution, engineering controls, administrative controls, then personal protective equipment. PPE is the last line of defense, not the first choice.

Flash point

The lowest temperature at which a liquid gives off enough vapor to ignite when exposed to an ignition source. Liquids with a flash point below 100 degrees F (37.8 C) are classified as flammable.

Lead-safe work practice

Methods for disturbing paint in pre-1978 buildings that limit lead dust and fume, such as wet sanding, containment, HEPA vacuuming, and prohibiting dry scraping or open-flame burning.

Respirable crystalline silica

Very fine dust from cutting, grinding, or blasting concrete and masonry that can reach deep lung tissue and cause silicosis. Wet methods, local exhaust, and fit-tested respirators control it.

Natural vs synthetic bristle

Natural hog-bristle brushes suit solvent-based and oil/alkyd coatings because water swells the bristles. Synthetic nylon or polyester brushes suit water-based latex and acrylic coatings.

Roller cover nap

The length of the roller fabric fibers. Use 1/4 inch for smooth gloss surfaces, 3/8 inch for standard walls, and 3/4 inch for stucco, brick, and rough exterior surfaces.

Airless sprayer

A spray system that atomizes coating by forcing it through a small tip at high pressure, typically 1,500 to 3,000 psi, without using compressed air.

HVLP spray

High volume, low pressure spraying. It uses a large air volume at low pressure for better transfer efficiency and less overspray than conventional air spray.

Plastic sheet moisture test

A test for masonry and concrete: tape a plastic sheet to the surface for 16 to 24 hours. Condensation under the sheet means moisture is still escaping and painting should wait.

Tannin bleed

Brown discoloration that leaches from knots and cedar or redwood into the topcoat. Seal knots and extractive woods with a shellac-based or stain-blocking primer before painting.

Galvanized metal preparation

New galvanized steel repels paint. Clean it, then apply a galvanized-metal primer or wash with a mild acid or vinegar solution to promote adhesion before coating.

Deglossing

Sanding or chemically dulling a glossy surface so a new coat can mechanically key to it. Skipping deglossing can cause peeling or flaking of the finish.

Boxing paint

Combining two or more cans of the same product and pouring back and forth to blend color and sheen evenly, preventing visible batch differences on the finished surface.

Pot life

The working time after a two-pack coating's parts A and B are mixed, during which it remains usable. Material left past pot life must be discarded, not thinned.

Volume solids

The percentage of a coating that remains as dry film after the solvent or water evaporates. It converts wet film thickness to dry film thickness: DFT = WFT times volume solids fraction.

Primer versus sealer

A primer promotes adhesion and blocks stains on a substrate. A sealer reduces absorption on porous surfaces. An undercoat provides a uniform base for the topcoat.

Wet film thickness

The thickness of a coating as applied, before drying. It is measured with a comb gauge and converted to dry film thickness using the product's volume solids percentage.

Back-rolling

After spreading coating in a W or M pattern, rolling over the area in one direction with light pressure to level the stipple and produce a uniform finish.

Recoat window

The manufacturer's stated time range for applying the next coat. Too early causes wrinkling or lifting; too late may require sanding to restore adhesion.

Orange peel

A bumpy, citrus-like surface defect caused by poor atomization, too much pressure or distance in spraying, or coating that is too thick or insufficiently thinned.

Faux glaze open time

The period during which a decorative glaze stays workable for blending and tooling. Retarders extend open time in hot, dry conditions; work in small sections.

Metallic finish lap marks

Dark or light streaks where overlapping passes meet on metallic or pearlescent coatings. They occur because particle orientation affects sheen; maintain a wet edge and spray or brush carefully.

Intumescent coating

A fire-retardant coating that swells into an insulating char when heated, protecting structural steel. It must be applied to a specified dry film thickness and inspected by gauge.

Clear topcoat over glaze

A transparent protective coat applied over decorative glazes and metallic finishes to improve durability, washability, and resistance to wear and handling.

Runs and sags

Downward flow of coating on a vertical surface caused by applying too heavy a coat, over-thinning, or spraying too close. Repair by sanding smooth and recoating.

Fish eyes

Small circular craters where coating pulls away from the surface, usually caused by oil, silicone, or wax contamination. Clean and degrease the substrate before recoating.

Cross-hatch adhesion test

A test in which a grid of cuts is scored through the coating and tape is pulled off. Lifting indicates that surface preparation or primer adhesion has failed.

Touch-up sheen match

A repair rule: use the same product batch and sheen for touch-up. A different sheen shows as a visible patch even when the color matches exactly.

Solvent rag can

A listed, self-closing metal container with a lid for solvent-soaked rags. It prevents spontaneous combustion and keeps flammable waste contained until disposal.

Dew point rule

The substrate temperature must be at least 5 degrees F (3 C) above the dew point. Otherwise condensation forms on the surface and the coating may fail to adhere.

Quality control file

Project records including batch numbers, product and safety data sheets, mix ratios, film thickness readings, environmental readings, inspection logs, and waste disposal receipts.

Toolbox talk

A short pre-task briefing that confirms scope, hazards, required PPE, and the day's quality targets before work begins, with attendance recorded for the safety file.