Using a metal or paper spray out card to match a plastic bumper is like matching apples-to-oranges. They are not the same. The award winning plastic spray out Bumper Cards replicate the same plastics used for OEM and Aftermarket bumpers so now you can match apples-to-apples and get a perfect color match the first time.
Any time plastic is sanded, scuffed or prepped in some way, that action changes the static characteristics of the bumper and causes paint and metallic particles to orientate differently than they do on metal or paper. The only way to duplicate those characteristic is to use the same material as the bumper, which is plastic, and to sand, scuff or prep the spray out card exactly the same way you sand, scuff or prep the bumper.
Treat the Bumper Card the way you would treat the bumper. If you follow the same steps on the Bumper Card, then you will be able to replicate exactly what will happen when you spray the bumper and you will get a perfect color match the first time. Eliminate re-work, eliminate wasted paint and increase productivity and quality.
Treat the cards exactly like you treat the bumper:
- If a wax or grease remover is required for the bumper, use it on the card
- If sanding or scuffing is needed on the bumper, do the same to the card
- If an adhesion promoter is applied to the bumper, do the same to the card
- If you prime the bumper, prime the card
- If you seal the bumper, seal the card
Source: Norton Abrasives