Sunuva!

this speaks a lot for body fillers. i know they have a bad rap. but most of the time when you remove dents you have to use filler anyways. at least a thin layer.

the secret is that it should be all down to bare metal before putting on the filler. wherever the filler overlaps paint it will separate and allow moisture and you will eventually get bubbles

the bare metal should be wiped with alcohol or another solvent before applying the filler as well. it will bond much better