Free C33 Identifying and Remedying Paint Failures and Defects Questions and Answers

Question 1

A painted surface shows a pattern of deep, interconnected cracks resembling crocodile skin. What is this defect called and what is the most likely cause?

Accepted Answer

Alligatoring, caused by applying a topcoat over an uncured primer.

Answer

This defect is known as alligatoring. It typically occurs when a rigid topcoat is applied over a softer or uncured undercoat, causing the top layer to crack as the bottom layer continues to shrink and shift.

Question 2

When painting a concrete block wall, you notice white, powdery salt deposits on the surface. What is the first step to properly remedy this issue before priming?

Accepted Answer

Remove the deposits with a wire brush and rinse the surface.

Answer

This condition is efflorescence, caused by moisture moving through the masonry and depositing salts on the surface. The salts must be physically removed with a wire brush and washed before any sealing or priming can be effective.

Question 3

Paint is peeling in large sheets from a previously glossy interior wall. What is the most probable cause of this failure?

Accepted Answer

The previous glossy surface was not sanded or de-glossed.

Answer

Glossy surfaces have poor adhesion. Failure to properly de-gloss the surface by sanding or using a chemical de-glosser before painting is a common cause of widespread peeling, as the new paint cannot form a strong mechanical bond.

Question 4

A freshly painted surface develops a rough, wrinkled appearance shortly after application. This defect is known as wrinkling. What is a common cause?

Accepted Answer

Applying the paint too thickly.

Answer

Wrinkling occurs when the top surface of the paint film dries faster than the underlying layer. This is often caused by applying the paint too thickly, painting in direct hot sunlight, or recoating before the previous coat has adequately cured.

Question 5

What is the primary cause of blistering in an exterior paint job?

Accepted Answer

Moisture trapped under the paint film.

Answer

Blistering is most often caused by moisture or solvent vapor being trapped beneath the paint film, which then expands due to heat from the sun. This pressure pushes the paint away from the substrate, forming bubbles or blisters. Identifying and resolving the moisture source is critical.

C33 - C-33 California Painting Contractor License Practice Test

C33 - C-33 California Painting Contractor License Practice Test

Free C33 Identifying and Remedying Paint Failures and Defects Questions and Answers