To ensure good adhesion over a bare plastic substrate requires that it be cleaned properly and coated with adhesion promoter before application of an undercoat. This standard operating procedure (SOP) covers using PPG's National Rule VOC system for preparing unprimed plastic.
Follow along with the outlined process below to learn how to properly prepare plastic parts for a repair.
- A technician should review a work order to ensure that all parts to be painted are present and repairs are understood.
- Surface Preparation: Option 1
- Follow Step 1 on the OC-1NR Plastic Prep System document. NOTE: It is best practice to remove the spray nozzle from the water hose end. Some nozzles create beading of water even though the part has been cleaned properly.
- Follow Step 2 on the OC-1NR Plastic Prep System document. NOTE: Use caution that SU4902 does not drip onto the plastic substrate surface.
- Follow Step 3 on the OC-1NR Plastic Prep System document. NOTE: Apply a light coat of SU4903/SUA4903 Advanced Plastic Bond. Medium to heavy wet coat application will compromise the integrity of the Plastic Prep System.
- Surface Preparation: Option 2
- Refer to OC-35 1K Compliant Adhesion Promoter document for use of SU470LV/SUA470LV.
- NOTE: It is best practice to remove the spray nozzle from the water hose end for the rinsing process. Some nozzles create beading of water even though the part has been cleaned properly. Hand shake SU470LV / SUA470LV well before each use.
- If there are scratches, chips, or other imperfections, apply primer surfacer. If deep imperfections, use flexible glaze filler, sand, then apply primer surfacer. Refer to all Product Data Sheets for the products that will be used on how to best complete your repair.
- If no imperfections, continue with the repair using your preferred PPG or Nexa Autocolor paint system undercoats and topcoats. Refer to the Product Data Sheet of the product that will be applied next for further information on how to best complete your repair.
NOTE: It is best practice for the highest level of integrity to use basecoat activator in solvent basecoat, especially for leading-edge parts and fascias.
NOTE: It is best practice for the highest level of integrity to use Adjuster and Modifier in waterborne basecoat, especially for leading-edge parts and fascias.
NOTE: Adhesion promoter must be sealed before topcoating with waterborne basecoat.
To maximize coating flexibility and chip resistance, follow product instructions for use of the flexible additive in the undercoat and clearcoat. Not all undercoats or clearcoats require a flexible additive due to their flexibility properties. Use an activator in the basecoat. Refer to all product bulletins for detailed instructions.