PSA: That cheap bondo job came back to haunt me in a big way

I did a quick fill on a 1998 Ford F-150 in Nashville about 4 years ago. Used some off-brand filler I got at a flea market to save the customer $30. Last month the guy rolls back in and the whole patch is bubbling up like a bad sunburn. Had to strip it all down to bare metal and start over, cost me 6 hours and a lot of embarrassment. Anyone else learn this lesson the hard way or am I the only one who tried to cut corners?

3 comments

3 Comments

clark.alex22d ago

Did you use any kind of metal prep or primer before slapping that filler on? I'm thinking the humidity in Nashville (or maybe even just surface rust) might have been the real problem, not the cheap stuff itself.

shanelee22d ago

Nah, I didn't bother with any special prep. Sanded it down with some 80 grit until it felt smooth and called it a day. People act like you need a chemistry lab just to slap some filler on a fender. The humidity thing is OVERBLOWN too. I've used this same brand on cars in way wetter climates and it held up fine for years. Cheap filler is cheap filler, plain and simple. Sometimes a rock chip or a bad spot just fails no matter what you do.

young.nora22d agoMost Upvoted

Surface rust is definitely the wild card here. Even a tiny bit you can't see will make the filler separate from the metal after a few months, especially in humid places like Nashville. A quick wipe with some phosphoric acid or even just a scuff pad with some acetone before the filler goes on makes all the difference. Think of it like this - you wouldn't just put spackle on a dusty wall, right?