Pro tip: that 'good enough' primer job will come back to haunt you

Had a customer bring back a 2020 F-150 we painted last fall, and the clear was already peeling on the hood. We rushed the primer sanding to 180 grit to get it out the door. Now we're redoing the whole panel on our dime. Anyone else get burned by skipping a step to 320?

2 comments

2 Comments

john4306h ago

Our shop manager in Toledo always said primer needs a mechanical tooth, not just a scratch pattern. Sanding to 180 leaves deep grooves that hold air and moisture. That trapped solvent eventually pushes up against the clear from below. It looks fine for a few months, then it just lets go. We switched to a three step primer sand years ago, 180, 320, then 500 before base. Never had a comeback for peeling after that.

nathan_barnes5h ago

Yeah, that tracks with what the old-timer at the local supply house told me. He called 180 grit scratches "little ditches" that never really seal up. Said you can watch the solvent boil out of them if you spray too wet. The step up to 500 before color makes total sense, even if it feels like overkill at the time. It's one of those things you only learn after seeing a job fail.