Undercoating
Undercoating1. Spraying primer
Primer is used to fill cavities in the putty and primer surfacer.
- Spray primer on the exposure area.
- Spray the 2-3 coats of primer on 2-3 coats over the area you applied putty.
- Apply primer to the back of the bumper if the damage is a tear or hole.
- Bumper primer (Reference)
- Warm the primer if the outside temperature is below 10 degrees C (50 degrees F).
- Follow the bumper primer manufacturer's instructions.
- Use a spray gun and a brush.
Drying
NOTE: Take care not to let the heat lamp deform the bumper during the drying process.
Dry the bumper primer thoroughly with an infrared dryer or other suitable methods.
Drying Time
2. Filling/Sanding
Apply putty to repair any holes or deep gouges.
- Apply the putty on the damaged area in 2-3 steps.
- Glue aluminum tape on the outside of the bumper, and apply putty from the other side of the bumper.
- Remove the aluminum tape after the putty dries, apply putty from the outside, and fill the hole.
Use a special polyester putty (Reference) and a putty knife.
3. Sanding
Sand the surface evenly, particularly at the area where the PP material and putty meet.
Use the flexible block and #240-#40-#600 sand-paper.
4. Air blowing / degreasing
Use alcohol, tack cloth, wax and grease remover.
5. Spraying primer surfacer
NOTE: Spray the bumper primer on the area where the PP material was installed and the around the putty.
- Spray the primer surface wider then the putty and painted surfaces of bumper primer.
- Spray 2-3 coats to get 20-30 microns of thickness.
- Use the 2-component type primer surfacer (gray) and a spray gun.
- Follow the materials manufacturer's instructions.
Drying
NOTE: Take care not to let the heat lamp deform the bumper during the drying process.
6. Sanding
After drying, wet sand the area of the intermediate coat
Use the #600 sandpaper.
NOTE: Do not use #600 or less
7. Air blowing/degreasing
Use alcohol, tack cloth, wax, and grease remover.
Also clean and degrease surfaces where the masking tape will be attached.