ACRP Workbook Chapter 29: Surface Preparation

When refinishing a collision repair, the appearance of the topcoat depends on the thoroughness of ___ preparation.

Surface

___ is the ability of two substances to bind together.

Adhesion

When one substance bonds to another through an interaction between atoms or molecules its called ___.

Chemical adhesion

In ___, the roughness of a surface allows a liquid topcoat to flow into tiny grooves and scratches and "grip" onto the surface.

Mechanical adhesion

True or false: When preparing surfaces for refinishing, always choose the most aggressive method that will do the job.

False

The standards for surface preparation can be divided into ___ categories or levels.

Three

True or false: Level 1 surface preparation requires the most amount of labor compared to the other levels.

False

During Level 1 Preparation, explain what is meant by clearcoat melting.

A melt is a tapered blend in clearcoat. The clearcoat is sprayed on a thin, tapered edge of a panel adjacent to the one painted to hide the edge of the new clearcoat and disguise the repair

The goal of level 3 surface preparation is to make a(n) ___ repair.

A. Noticeable

B. Cheap

C. Undetectable

D. Expensive

C. Undetectable

Which of the following steps is the first procedure in basic vehicle surface preparation?

A. Plan the repair

B. Inspect the surface carefully

C. Paint the area

D. Sand the area

B. Inspect the surface carefully

True or false: One mil is 0.1"

False

Match the description to the vehicle paint problem

A. Appears as reddish brown grains on bare steel

B. Gradual change in color due to paint pigment breakdown

C. Weather-beaten paint with no gloss due to paint binder breakdown

D. Creates a weak, flakey area with bubble-like paint blisters on the surface

E. Caused by loss of adhesion between the topcoat and primer

F, Begins as tiny slits in the paint surface often caused by UV exposure

A. Surface rust

B. Fading

C. Chalking

D. Internal rust

E. Peeling

F. Cracking

Explain the difference between painted, blended, and melted in reference to how a vehicle panel will be refinished with basecoat and clearcoat.

-Painted: The entire panel will be sprayed with basecoat and clearcoat

-Blended: The panel will be partially sprayed with basecoat and fully sprayed with clearcoat

-Melted: The panel will be partially sprayed with basecoat and clearcoat

True or false: Repairs of external vehicle panel surfaces may damage internal surfaces.

True

A separate vehicle panel makes a good edge to end ___ so a repair is unnoticeable.

A. Refinishing

B. Welding

C. Bending

D. Pulling

A. Refinishing

An entire vehicle should be washed with ___ before starting paint preparations to ensure a quality paint job.

A. Epoxy

B. Soap and warm water

C. Silicone

D. Wax

B. Soap and warm water

Describe how to remove vehicle molding that is attached with clips.

Push the molding up or down to unlock the molding from the clips then slide it off

Which of the following products is used to remove tar and other oil-soluble contaminants?

A. Pre-sand solvent

B. Wax

C. Soap and water

D. None of the above

A. Pre-sand solvent

Removing all paint from a surface to leave just the bare metal is known as ___ the surface.

Stripping

Upon application, a(n) ___ forms a seal on the surface to prevent evaporation of the active ingredients as they break down the paint.

Stripper

Which of the following materials is not an abrasive material that would be used for media blasting?

A. Sand

B. Aluminum oxide

C. Plastic beads

D. Newspaper shavings

D. Newspaper shavings

In collision repair, due to the possible secondary damage it can cause, to what use should aggressive media blasting be confined?

Cleaning before/after welding and cleaning rusty metal

When sandpaper stripping paint from a vehicle panel, keep the sander moving to minimize ___ which can melt or damage an area.

Heat buildup

True or false: When scraping a peeling topcoat with a razor, the angle between the blade and the surface is important for success.

True

After removing OEM paint on a vehicle with a power sanding tool, a surfacer or sealer will fill in the 320-grit scratches; ___ will not.

Basecoat

True or false: A scuffed surface does not require a sealer or surfacer to fill scratches.

True

Essential for an invisible repair, proper ___ produces a gradual taper of the paint edges around a repair.

Featheredging

As the first step of featheredging, there should be ___" of each paint layer exposed after using 80-grit sandpaper.

A. 1/16"

B. 1/8"

C. 1/4"

D. 1/2"

D. 1/2"

What is the purpose of back taping?

The edge nearest the area to be painted is rolled back; this feathers in the overspray, tapering the paint edge and making it less visible

Undersurfaces, such as wheel wells, can be protected from overspray with ___.

Liquid mask

Which of the following is a rule to follow when masking?

A. Remove as many obstructions as practical

B. Work from inside to outside

C. Wash and blow off panels before paint masking

D. All of the above

D. All of the above

When bare metal is exposed to air, it will almost instantly begin to ____ as it reacts with the moisture and oxygen in the air.

Rust

A conversion coat adds a layer of ___ to bare metal.

Phosphate

True or false: Do not spray undercoat over an area that has not been sanded or scuffed because the undercoat will not stick.

True

What are the two types of primer used in automotive refinishing?

Self etching primer and epoxy primer

What problems are caused by an incorrectly mixed thick surfacer?

Instead of completely filling sanding scratches, the thick surfacer bridges over the scratches, leaving a hollow void below. As the surfacer cures, the surfacer and topcoat will sink into the void, causing an outline of the scratches to appear in the paint

There are three layers of paint showing in the featheredge. How many coats of surfacer should be applied?

A. 2

B. 3

C. 4

D. 5

B. 3

How should a technician prep a featheredged surface if the undercoat is exceptionally thick?

Apply two part spot putty over epoxy primer. Allow it to cure then sand with 80-, 180-, and 320-grit sandpaper. When sanding with the 80- and 180-grit sandpaper, sand only on the spot putty. Featheredge the spot putty into the surrounding paint with 320-grit sandpaper on a block. Apply three coats of surfacer to the block sanded two part putty.

True or false: Painting improperly cured surfacer will cause shrinkage and sanding scratches.

True

True or false: An infared dryer cures paint by cooling the surrounding air and lowering the temperature of the entire vehicle.

False

Why does surfacer need to be block sanded?

It removes high spots, leveling the entire repair to the same height as the surface surrounding the repair

The absence of guide coat with no exposed bare metal areas (high spots) indicates a(n) ___ surface.

Level

True or false: While sanding surfacer, pressure should be applied to just one end of a sanding stick to properly level the area.

False

Disregarding speed, which type of block sanding better levels surfacer and is more accurate?

Hand block sanding

During finish sanding, a technician should sand in a(n) ___ motion to remove scratches made while block sanding.

A. Up and down

B. Circular

C. Triangular

D. Digging

B. Circular

Keep the vehicle panel surface ___ while finish sanding.

A. Bent

B. Hot

C. Wet

D. All of the above

C. Wet

Collecting dust during sanding operations with a(n) ____ sander will lessen surface cleanup time and airborne particles in a shop.

Vacuum

If panels will be painted on the vehicle, which of the following areas is masked for topcoat first?

A. Panel openings

B. Windows

C. Wheels and wheel openings

D. Adjacent panels

A. Panel openings

The ___ of a panel opening will not be directly exposed to overspray as the panel is painted.

Blind side

Applied to the edge of one panel, ___ fills panel gaps to protect from overspray in the same way as back taping and paper.

Foam tape

Depending on the level of surface preparation, some shops will simply ___ a window molding rather than raise it.

Mask

Explain how to mask a windshield or back glass opening with masking paper if the glass has been removed.

Cut a piece of cardboard to fit the opening then apply masking paper over the cardboard

Which of these items should not be used to mask a wheel or wheel opening?

A. 18" masking paper and tape

B. Single-use plastic wheel coverings

C. Towels

D. Liquid mask

C. Towels

True or false: A body line can be used as a refinish edge if it runs the length of the panel.

True

Panels adjacent to the spray area should be covered with 18" ____.

Masking paper

A(n) ___ should be unfolded and gently glided over a surface before paint is applied to remove super fine contaminants.

Tack cloth/rag

___ is used to fill panel joints and gaps between panels

A. Body filler

B. Seam sealer

C. Pre-sand solvent

D. None of the above

B. Seam sealer

Available in an aerosol can, ___ forms a thick, clear, protective layer on the lower surfaces of the vehicle.

Rocker panel spray

True or false: To ensure proper adhesion, basecoat should be applied over rocker panel spray while while it is still wet.

False

True or false: If a scratch is too deep to be buffed out, it must be sanded and featheredged.

True

True or false: Pinholes in body filler can be effectively filled with putty.

True

What appears in a clearcoat if shrinkage occurs in the area.

Scratches will appear

Describe the steps in surface prepping an appearance weld.

Evaluate the surface and plan the repair. Remove obstructions, clean the panel, dress the weld. Use a cutoff tool to grind away most of the weld bead and any remaining high spots. Fill slight voids with putty and featheredge. Blow off sanding dust and clean the panel. Mask the repair area for undercoat and apply self etching primer and surfacer. After primer and surfacer has cured, block sand the repair, blow off sanding dust, clean the panel with pre-paint solvent, and mask for the topcoat.

True or false: When repairing rust, after grinding, the rust will look like large red rectangles and triangles in the metal.

False

____ tapers coats of paint on a vehicle panel, making a gradual transition from refinish paint to existing paint.

Blending

If a vehicle panel is ___, the adjacent panels will be blended to better match the refinish paint.

A. Twisted

B. Crushed

C. Rusted

D. Replaced

D. Replaced

A(n) ___ is also known as a solvent blend.

Melt

Pre-painting inaccessible areas of new replacement parts prior to installation is known as ___, edging, or cutting in.

Trimming

True or false: An example of a vehicle panel that should be trimmed is the inside of a door.

True