Information on Tri-Coat Paint Repair. Saturn Saturn 1994

For 1990-2009 cars

# Information on Tri-Coat Paint Repair

Subject: | Information on Tri-Coat Paint Repair

Models: | 1994 Saturn homecoming commemorative sedan (HCS)

### Purpose

The purpose of this bulletin is to familiarize the technician with tri-coat paint repair. This information is required since the 1994 Saturn homecoming commemorative sedan (HCS) will be finished with a new pearl shell tri-coat system.

NOTE: A tri-coat Paint Repair training program, course number 22001.41, is available through General Motors Service Technology group, for Canadian Dealers, use course number 22010.08. Refer to the Retail Training Catalog of Programs and Services, page 7, General Information for enrollment procedure.

### Comparing Basecoat/Clearcoat and Tri-Coat Finishes

The Ultimate Basecoat/Clearcoat Color Shade

Light that penetrates the surface of the cured paint film, reflects off the aluminum flakes, then passes around the pigment of varying densities which produces the ultimate color shade.

The Ultimate Pearl Luster Effect

Light striking the applied film of titanium dioxide on the flakes of mica creates a the pearl luster effect by allowing the light to deflect at different angles. The light deflection determines the ultimate pearl luster you see.

The repair of these white pearl colors requires different techniques and a different application process. Many of the conventional application techniques used on basecoat/clearcoat metallic colors do not apply when repairing a tri-coat finish.

Basecoat/clearcoat metallic colors can be adjusted by the following variables:

1. Reduction -- the amount and choice of solvent
2. Air pressure
3. Gun distance
4. Fluid adjustment
5. Fluid tip size

The color is affected as follows:

• | Higher air pressure/increased reduction causes a metallic color to shift to the light side of the face and dark on the flop.

• | Lower air pressure/decreased reduction causes a metallic color to shift to the dark side on the face and go light on the flop.

Theoretically, when a metallic paint film is applied wet, as it would be at a lower air pressure and lower reduction, the aluminum flake settles deep in the paint film and is surrounded by the color pigment causing a darker appearance. The color reacts in the opposite when the variables are reversed.

This theory does not apply to the whit pearl tri-coat system. The white basecoat is a solid material, therefore, will not be sensitive to the same variables that affect metallic colors. On the other hand, the pearl coat, or mid coat, is very sensitive to film build. For this reason, a let-down panel should be used to determine the number of pearl coats required to match the OEM finish. This tool should be made prior to starting a repair. The let-down panel is used to match the paint of the repair vehicle.

### The Let Down Panel

The let down panel should be used as an aid to determine the appropriate number of pearl coats ," that" will" be" necessary" to" achieve" a" proper" color" match." this" is" done" by" comparing" the" various" pearl" coat" film" build" areas" on" the" let" down" panel" to" a" panel" adjacent" to" the" repair" area." prior" to" starting" the" repair." it" can" be" made" in" the" following" manner." refer" to" the" illustration" on" the" facing" page.

1. Apply the white base to hide. Paint code 40, WA9563.
2. Mask the panel in 5 sections leaving the first section exposed.
3. Apply a single medium wet coat of pearl material.
4. Remove the masking paper from the second section.
5. Apply a medium coat over the entire uncovered area. Repeat the above steps until the 5 sections are completed, leaving only one coat on the last.
6. NOTE the let-down patch should illustrate 5 different film builds of pearl coat.

Once the panel is dry, mask off one half of the panel dividing it lengthwise. Apply two coats of clear on the unmasked half of the panel. Remove the masking paper and let the panel dry.

### Paint Repair Technique Options

The successful repair of tri-coat finishes will depend upon the painter's repair technique and their experience with these colors. Remember, all tri-colors are designed to be repairable.

When selecting and using materials:

• | Use only top quality materials.

• | Follow the manufacturer's instructions.

• | Do not mix different brands of materials

The success of a paint repair depends upon:

• | An acceptable color match.

• | A good blend with the original color.

• | Proper buildup of the pearl luster coat.

• | A similar gloss and smoothness of the finish.

Important: The pearl luster is very sensitive to film buildup. As the film build of the pearl luster coat increases, the color becomes darker. If the [pearl luster becomes too dark to blend into adjacent areas, reapplication of the white base coat followed by the pearl luster coats will be required.

Paint repair techniques for tri-coat finishes consist of the following options:

1. Spot/partial repair.
2. Full panel repair -- Picture frame, without blending.
3. Full panel repair -- With blending of the pearl luster coat.

Caution: If product containing isocyanates are used, it is mandatory that adequate respirator protection be worn. Examples of such protection are air line respirators with full hood or half mask. if not available, use a vapor/particulate type respirator that the respirator manufacturer recommends as effective for isocyanate vapor and mist (unless local regulations prevail). Such protection should be worn during the entire painting process. Persons with respiratory problems or those allergic to isocyanates must not be exposed to isocyanate vapors or spray mist.

#### Typical Let-Down Panel

White Basecoat and 5 Coats of Pearl Luster
Uncleared | Cleared
White Basecoat and 4Coats of Pearl Luster
Uncleared | Uncleared
White Basecoat and 3Coats of Pearl Luster
Uncleared | Uncleared
White Basecoat and 2Coats of Pearl Luster
Uncleared | Uncleared
White Basecoat and 1Coats of Pearl Luster
Uncleared | Uncleared

### Repair Method

Spot/Partial Repair

Use standard repair procedures for component panel repair. Sand, prime and compound the same as for any paint operation.

1. Wet sand the primed areas and areas where the base color will be applied with #400 grit sandpaper.
2. Apply primer-surfacer as required. Follow labeled instruction.

Important: For best results, light color primers or sealers should be used under the base white coat.

3. Compound or wet sand the areas to be painted with ultra fine or finer sandpaper and wash the entire area with a cleaning solvent.
4. Apply the base color to hide. Feather out the base white in the blend areas. Use the let-down panel to determine the number of pearl luster coats required to match the adjacent panels.
5. Apply the pearl luster coat over the white base area then blend beyond as required. Allow sufficient flash time in between coats.
6. Apply clearcoat over the complete panel.

Full Panel Repair -- Picture Frame Without Blending

1. Wet sand the complete panel with #400 grit sandpaper.
2. Apply primer-surfacer as required. Follow labeled instruction.
3. Compound or wet sand the complete panels that will be blended into using ultra fine or finer sandpaper. Wash the entire area with a cleaning solvent.
4. Apply the base color to hide. Use the let-down panel to determine the number of pearl luster coats required.
5. Apply the pearl luster coat over the complete panel until color match is acquired. Allow sufficient flash time in between coats.
6. Apply clearcoat over the complete panel.

Full Panel Repair -- Blending Into Adjacent Panels

1. Wet sand the complete panel with #400 grit sandpaper.
2. Apply primer-surfacer as required. Follow labeled instruction.

Important: For best results, light color primers or sealers should be used under the base white coat.

3. Compound or wet sand the complete panels that will be blended into using ultra fine or finer sandpaper. Wash the entire area with a cleaning solvent.
4. Mask off the blend panels and apply the basecoat to hide on the repair panel. Use the let-down panel to determine the number of pearl luster coats required to match the adjacent panels.
5. Apply the required number of pearl luster coats to the panel, allowing sufficient flash time, in between coats and let dry. Pull back the masking paper from the adjacent panel to check for color match. If the repaired panel; is lighter than the adjacent panels, replace the masking paper and apply additional pearl luster to the panel. Allow sufficient flash time in between coats.

• | Remove masking paper from the blend panels and apply one or more coats of pearl luster over the repair panel and onto the adjacent blend panel using an arching motion

• | If additional coats are necessary, extend each coat beyond the last on the blend panel.

6. Clearcoat the complete repair and adjacent panels.

#### Tri-Coat Product Information

Paint Code | Color Name | WA# | Dupont | PPG/Ditzler | Martin-Secour | Sherwin-Williams ACME/Rogers | R-M Inmont
--- | --- | --- | --- | --- | --- | --- | ---
40 | White | 9563 | B9155-B/C | 4336-B/C | 44126 | 44126-B/C | 21055-B/C
16 | Pearl | 287A | B9554/B9555 | 5008 | 50599/50600 | 50599/50600 | 24489