CAADE Repair and Refinishing Processes 3 — Questions and Answers
Question 1: When estimating refinish labor time using a collision estimating guide, 'blend time' is used to account for:
- Extra time to sand and smooth body filler
- Transitioning the new paint color into the adjacent panel for a seamless match (Correct answer)
- The time required to tape and mask adjacent panels
- Additional clear coat passes on heavily damaged areas
Correct answer: Transitioning the new paint color into the adjacent panel for a seamless match
Blend time compensates for the labor of feathering and transitioning a new color coat into the existing finish on bordering panels.
Question 2: What is 'sand-scratch swelling' in automotive refinishing?
- Expansion of body filler due to moisture absorption
- Solvent penetrating old paint causing underlying sanding marks to telegraph through the new finish (Correct answer)
- Raised primer blisters caused by trapped air
- Surface irregularities caused by incorrect reducer selection
Correct answer: Solvent penetrating old paint causing underlying sanding marks to telegraph through the new finish
Solvents in fresh topcoats can swell and re-open old sanding scratches in the substrate, making them visible in the cured finish.
Question 3: In a structural repair, a sectioning joint on a unibody rail is best located:
- At the closest point to the damaged area to minimize labor
- In an area specified by the OEM repair procedure, away from stress-concentration zones (Correct answer)
- At any factory weld seam for convenience
- Midway between the front and rear of the vehicle
Correct answer: In an area specified by the OEM repair procedure, away from stress-concentration zones
OEM procedures designate sectioning locations where the geometry, overlap, and welding specs ensure restored structural integrity.
Question 4: Which type of paint system requires the application of a separate clear coat to achieve gloss and protection?
- Single-stage enamel
- Two-stage (basecoat/clearcoat) system (Correct answer)
- Acrylic lacquer
- Direct-gloss polyurethane
Correct answer: Two-stage (basecoat/clearcoat) system
Two-stage systems use a pigmented basecoat for color and a separate clearcoat for gloss, UV protection, and durability.
Question 5: When a repair estimate includes 'overlap allowance,' this refers to:
- Extra material cost for purchasing a full panel
- A reduction in labor time when multiple adjacent panels are refinished together (Correct answer)
- Additional time for masking overlapping trim pieces
- The extra clear coat applied over blend zones
Correct answer: A reduction in labor time when multiple adjacent panels are refinished together
Overlap allowance deducts labor time because a technician can refinish adjacent panels more efficiently in a single setup than individually.
Question 6: Plastic identification codes (e.g., PP, TPO, ABS) on bumper fascias are important during refinishing because they:
- Indicate the part's OEM part number
- Determine which adhesion promoter or flexible additive is required (Correct answer)
- Show the correct primer color to use
- Specify the recommended reducer for that climate
Correct answer: Determine which adhesion promoter or flexible additive is required
Different plastic substrates require specific adhesion promoters or flex additives; using the wrong product causes peeling or cracking.
Question 7: When using a DA (dual-action) sander for featheredging, the primary advantage over a straight-line sander is:
- It removes material faster on flat panels
- It produces a swirl pattern that reduces the risk of creating deep scratches and heat buildup (Correct answer)
- It is more effective on bare metal substrates
- It eliminates the need for wet sanding after painting
Correct answer: It produces a swirl pattern that reduces the risk of creating deep scratches and heat buildup
The random orbital motion of a DA sander minimizes linear scratches and reduces heat, making it safer for featheredging repairs.
CAADE Repair and Refinishing Processes 3
When estimating refinish labor time using a collision estimating guide, 'blend time' is used to account for: