Fed up with people using Bondo to fill dents on aluminum panels

Had a truck come in last week where someone slopped filler over an aluminum tailgate dent. It bubbled up and cracked out after two months because the filler can't bond right. You can't just treat aluminum like steel, how many more times do I have to say this?

3 comments

3 Comments

pat_fisher241mo ago

Doesn't regular Bondo have a marine grade version specifically for aluminum though? I've seen some long lasting repairs where they just rough up the surface good and use that without any special etching process.

seanjackson1mo ago

My buddy Dave tried to fix an aluminum boat with regular Bondo last summer. It looked good for about a week, then it just peeled off like cheap tape. I told him the same thing. You gotta treat it like a completely different animal. @eva_thompson is spot on about that etching step, its not optional. Ive seen guys skip the etch and wonder why their work fails three months later. The moisture reaction is real and it will ruin your whole repair.

eva_thompson1mo ago

You gotta sand down to bare aluminum, etch it, then use a two part epoxy primer before any filler touches it. Bondo's fine for steel but that moisture reaction with aluminum is no joke.