Specialized Painting Processes - Soft Chip Guard Primer Coat

NOTE: Depending on the destination, a soft chip guard primer coat is applied. If this chip guard primer coating is applied, read following precautions and follow coating procedures.

1. Soft Chip Guard Primer Coat

Sectional view of paint coats
General Safety Precautions

The removal of paint and undercoating by stone chips immediately exposes metal to the atmosphere, causing it to oxidize. The thickness of this oxidation increases if the process continues unchecked. Soft chip guard primer protects against damage due to the impact of such objects:
The soft chip guard primer coat is applied over the E.D. (electrostatically deposited) primer. It is followed by the guide coat and the topcoat.
Soft chip guard primer produces a smooth surface when dry. It should be sprayed so the thickness of the protective film is 20 microns.
Soft chip guard primer coat is then applied to the most susceptible areas.
Spray the primer-surfacer (dual-component urethane primer-surfacer) on the soft chip guard primer coating areas when you replace parts using soft chip guard primer coat.
Coating Processes
Wear goggles or safety glasses to prevent eye injury.
Ventilate when spraying undercoat.
1.
Sanding the replacement part.
Use a double action sander and P400 sandpaper.
NOTE:
Do not over sand the edges or corners of the part.
Do not expose base metal.
2.
Air blowing/degreasing.
Use alcohol, and wax and grease remover.
3.
Protect from overspray.
Use masking tape and protect the related areas from overspray.
4.
Spraying primer-surfacer:
Spray about four to five coats to get 20 microns of thickness. One coat deposits about 5 to 7 microns.
Do not try to cover the surface with one heavy coat. Applying several thin coats is recommended.
Use a dual-component urethane primer surfacer and a spray gun.
Mix the primer-surfacer with the correct ratio of hardener and solvent.
Follow the primer-surfacer manufacturer’s instructions.
5.
Drying.
After spraying primer surfacer, allow 7 to 10 minutes of set-up time, then force dry it with infrared lamps or an industrial dryer.
6.
Fine sanding:
Check that the primer-surfacer has dried thoroughly, then sand the primer-surfacer.
Use a double action sander and P400?P600 sandpaper.
7.
Apply intermediate coating and topcoat.