Metal finishing Q&As since 1989

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Automotive Paint Finish

I have recently restored a 1955 Thunderbird. We painted it with a polyurethane based paint. We sanded the surface to get an above average finish. Then buffed with a white buffing compound. But I'm still not completely satisfied. I would like suggestions on my next step to get a perfect finish.

Thank You for your input....

Jerry Moore
Auto Restoration - Midland, Texas
2004

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2004

I found some information on PPG's website that might help you...

Although apparently smooth and evenly applied, the surface lacks shine.

Cause Microscopic roughness of the surface, which may result from:

a) Poor hold out of primer, or the application of topcoat over primer which is not thoroughly dry.

b) Poor quality or incorrect thinner, or the use of additives in the paint.

c) Incorrectly prepared or poorly applied paint.

d) Application over a poor substrate

e) Excessively slow drying due to high humidity or low temperature.

f) Solvent fumes or exhaust gases attacking the surface.

g) Surface contamination by wax, grease, oil, soap or water.

h) The use of strong detergents or cleaners on a newly painted surface, compounding too soon after painting or using compound which is too coarse.

Prevention a) Use an approved primer, and allow to dry thoroughly before applying the topcoat.

b) Use only recommended thinner and approved additives.

c) Ensure that the paint is stirred thoroughly, apply under the correct conditions using proper spraying techniques.

d) Prepare the substrate thoroughly.

e) Ensure that the paint dries under warm and dry conditions.

f) Ensure good, draught free air over surfaces whilst drying.

g) Wipe the undercoat with solvent and dry thoroughly before applying the topcoat.

h) Avoid using strong detergents or cleaners on newly painted surfaces. Do not compound paint until thoroughly hard and always use the correct grade of compound.

Rectification Normally the shine may be restored by rubbing down with abrasive compound and polishing. If the dulling is too severe for this to yield satisfactory results, rub down the topcoat and repaint.

Jasiel
- Lehigh Acres, Florida