Remember when the old guy at the shop told me to never use Bondo on aluminum panels?

He was right, I tried it on a 2005 Honda Civic fender last month and it peeled off like cheap paint after two days - has anyone else had that kind of failure with fillers on aluminum?

3 comments

3 Comments

lewis.brian14d ago

Wait did you sand the aluminum down to bare metal first and use an etching primer or just go straight to laying the Bondo on. Aluminum needs special prep because of the oxidation layer, it'll reject just about anything that's not made for it. What kind of prep work did you actually do before you put that filler on?

walker.julia14d ago

Scuffed it up with 80 grit and wiped it down with acetone before laying the filler on, and it held for a solid two years before I sold the boat. Might've just gotten lucky, but a buddy of mine did the same prep on his trailer and it's still going strong.

garcia.jake14d ago

85 grit sandpaper and a prayer was my prep work, so yeah @lewis.brian I definitely skipped the etching primer (rookie mistake, I know). Guess I learned the hard way that Bondo and aluminum don't mix without a little extra effort.