Tried wet sanding with a lower grit than recommended and it changed my whole approach

I was doing a bumper repair last Tuesday on a 2012 Civic and ran out of 800 grit, so I grabbed some 400 instead thinking it would just take longer to finish out. Ended up with way better adhesion on the primer and saved a step because the scratches were fine enough to fill smooth. Has anyone else experimented with dropping grit on purpose like this or am I just getting lucky?

3 comments

3 Comments

nancygrant23d ago

Wait, @david37 have you ever actually tried it with a lower grit on a plastic bumper? I used to be all about sticking to the recommended grit religiously, but after reading some forums and experimenting, I totally changed my mind. The key is finding that sweet spot where the scratches are deep enough to grab the primer but fine enough to hide under final coats. On that Civic bumper, the 400 grit left a perfect tooth for the primer to bite into, and I didn't see any show-through even after wet sanding the final clear coat. Honestly, it saved me time and gave better results than my usual 800 grit routine. Just gotta test it on your specific plastic first to avoid the scratch issue @avery_lopez mentioned lol.

avery_lopez23d ago

Better adhesion" is probably just you getting lucky with that specific plastic blend on the Civic. I've tried the same shortcut and ended up with visible scratch marks showing through my final coat EVERY time.

david3723d ago

Wait, you've actually seen scratch marks show up through the final coat from skipping the sanding step?