ASE Practice Test (B2: Painting & Refinishing) 2 Flashcards

A technician is preparing a repaired panel for painting. After sanding with 180-grit sandpaper, which action is required before applying primer?

Answer: Clean the surface with wax and grease remover then apply a sealer or etching primer

180-grit sandpaper leaves scratches that are too coarse for topcoat adhesion. The surface must be cleaned with a wax and grease remover to eliminate silicone and contaminants that cause fish-eye. An etching primer or sealer is then applied to fill scratches, promote adhesion, and provide a uniform foundation before applying primer-surfacer or topcoat.

When mixing a two-stage (basecoat/clearcoat) system, the painter notices the clearcoat is too thick. What is the MOST likely result if it is applied at this viscosity?

Answer: Runs, sags, solvent pop, and poor atomization

Clearcoat that is too thick (high viscosity) will not atomize properly from the spray gun. The result is poor flow-out, runs, sags, and trapped solvents that cause solvent pop (small bubbles or craters). Material must be reduced according to the manufacturer's mix ratio and viscosity specifications, adjusted for temperature and humidity conditions.

Which type of paint defect appears as a wrinkled or shriveled surface texture after applying a new coat of paint?

Answer: Lifting

Lifting occurs when the solvents in the new paint coat attack and swell the existing finish below it. This causes the old paint layers to wrinkle or shrivel. It commonly happens when applying lacquer or enamel over an incompatible previous finish, or when applying a strong-solvent product over an uncured previous coat. Proper sealing and finish compatibility prevent lifting.

What is the purpose of a guide coat when block sanding a primer-surfacer?

Answer: It reveals low spots and high spots so the technician knows when the surface is flat

A guide coat is a thin, contrasting-color spray (or dry powder) applied over primer before block sanding. As sanding progresses, the guide coat is removed from high spots first while remaining in low spots. Any area where guide coat remains after sanding indicates a low spot that requires additional filler or primer. When the guide coat is fully and evenly removed, the surface is flat.

A painter sprays metallic basecoat and notices the flakes appear dark and "mottled" in the center of the panel. What is the MOST likely cause?

Answer: The gun was held too close or moved too slowly, causing heavy wet coats

Metallic flakes in basecoat orient parallel to the surface for maximum sparkle when applied in thin, even passes at the correct distance. Holding the gun too close or moving too slowly deposits too much wet material. The heavy wet coat causes the flakes to orient randomly and sink or cluster, creating dark, mottled areas. Correct gun distance and pass speed are critical with metallics.

Which personal protective equipment (PPE) is MANDATORY when spraying isocyanate-containing two-component (2K) clearcoat?

Answer: A supplied-air respirator (SAR) or PAPR with appropriate cartridges

Isocyanates in 2K clearcoat and hardeners are severe respiratory sensitizers. Once sensitized, even tiny exposures can trigger asthmatic reactions. NIOSH mandates a supplied-air respirator (SAR) or a properly fitted air-purifying respirator with OV/P100 cartridges specifically rated for isocyanates. A dust mask offers no protection against isocyanate vapors.