Before applying the primer-surfacer, be sure to inspect the coating surface. Deep surface damage will remain even after the primer- surfacer is applied. Then it would become necessary to repair the damage after the primer surfacer is applied.
When it is necessary to sand deep surface damage, use a double action sander with P240 to P400 sandpaper.
Use a hand file together with P400 to P600 sandpaper to remove damage where a sander cannot be used.
?2.
Scuffing (for primer-surfacer coating):
Use a double action sander with P320 sandpaper to sand the hairline sanding scratches on the filled/putted surface.
Use a hand file, for the areas a sander cannot access, along with P600 sandpaper to remove sanding scratches.
Apply scuffing up to approximately 10 cm (4 in) away from the edge of filled/puttied area.
?3.
Air blow all dust, dirt and body filler/putty residue from the area.
?4.
Apply reverse masking slightly outside the primer-surfacer coating area with a margin.
?5.
Degrease and clean up the primer-surfacer application area.
2.
Preparation of Primer-Surfacer:
Spec of Primer-Surfacer (reference)
3.
Applying and Drying Primer-Surfacer: The nozzle diameter of spray guns used for primer-surfacer should be 1.5 to 1.8 mm (0.050 to 0.070 in), depending upon the size of the repair area.
?1.
Retouching. Spray primer-surfacer to the entire repair area.
?2.
Within the retouch area, spray while making the surface flat. Repeat two to three times based on the basecoat condition.
?3.
Allow sufficient flash time.
?4.
Continue to apply, narrowing the application surface to avoid overspray.
?5.
Dry the primer-surfacer. Force-dry after allowing sufficient set-up time.
4.
Confirmation of Primer-Surfacer Coating Surface and Spot Putty:
Thoroughly inspect the primer-surfacer coated surface for hairline sanding scratches and cavities.
When scratches or cavities are found, fill them with spot putty (touch- up putty).
Sand the spot putty and primer surfacer coated surface by dry or wet sanding to finish the surface.
NOTE: Do not over sand as it will result in exposure of bare metal or body filler.
Dry Sanding:
For hand sanding, use P600 to P800 sandpaper together with a rubber sanding block. Continuously remove any sanding dust to avoid clogging the sandpaper.
When using a double action sander, use P400 sandpaper.
Wet Sanding:
Manually sand using P400 to P800 wet-or-dry sandpaper.
While wet sanding, use a sponge soaked with water to keep the sanding surface sufficiently moistened.
?2.
Completely dry the surface with a compressed air blow gun and infrared lights after wet water sanding.
NOTE: Use a dry sprayed guide coat to visually check surface flatness.
6.
Inspection and Repair after Sanding:
Inspect the state of the finished primer-surfacer coated surface.
If the surface is OK without any thin or uncoated spots, move on to the topcoating process.
If any defect is found on the surface including thin or unpainted spots, exposed filler/putty, or bare steel panel, repeat the primer-surfacer coating and sanding processes.
