• Having site issues? Contact Dub@southernPolyurethanes.com

Gm Primer - Sandblast or scuff before epoxy primer?

I am doing collision repair on a 2015 traverse and I have inner and outer frame rails new from GM in their black primer (I am assuming an epoxy of some sort) should I sandblast all the GM primer off and primer with SPI Epoxy or should I be fine just scuffing with red scotchbrite and priming with 3 coats SPI epoxy before plug welding them together?
Thanks for the replies. One other question - is a red schotchbrite enough or should I sand it with 180 ? it has a lot of different curves and crevices to roughen up.

Thanks again for the replies!