This standard operating procedure covers PPG's recommended process for sanding primer surfacer during your repair. Before beginning any repair, be sure to always wear the recommended safety protection for the job.
1. Apply a Guide Coat
When preparing to sand a primer surfacer, a best practice is to first apply a “guide coat”. This application helps detect any low spots or minor imperfections prior to sanding the primer surfacer.
2. Block Sanding
Next, block sand the repair area with P320 grit until the guide coat is removed, then re-apply the guide coat.
3. Sand with Dual Action Sander
Then, use a dual action sander with P400 — again, removing all of the guide coat.
4. Sanding For a Basecoat Blend
For a basecoat blend, prepare the rest of the panel, first using P600 grit, following with P800 grit where the clearcoat will extend. Then use a grey scuff pad to prepare the panel edges for the basecoat blend.
5. If Applying Wet-on-Wet Sealer
If applying a “wet-on-wet sealer” before topcoating, clean the repair with waterborne cleaner and dry thoroughly with clean towels.
6. If NOT Applying a Wet-on-Wet Sealer
If a wet-on-wet sealer is not being used, finish dual action sanding with P600 grit.
7. Precaution for Exposed Bare Metal
Should any bare metal become exposed during the repair, a self-etching primer should be applied, following the product instructions.
You’re now ready to proceed preparing the panel for a spot repair, following the process instructions for a basecoat blend.
For more in-depth training resources, visit us at us.ppgrefinish.com/training.