Will a paint stripper hurt body filler if it runs down a panel I'm stipping onto a spot I recently repaired with filler ?

Yes it will destroy it.

so l have to strip the car before l start the bodywork ?

Stripper destroys everything that is not metal.... cement floor, gloves, pants, skin :eek: . I found it worked best when I didn't let it sit as long as the directions said. As soon as it started to crinkle good but still looked wet, start scraping.

Good Luck
Robb

PS. I couldn't go by a thread with this title and not open it :D

It works great, but you need to be prepared to start from scratch. It sucks! But it is the best way to get the best results.

You can skip the big bondo spots with the stripper
if you don't want to do all the bondo work again.
You have to be sure that the exsisting bondo work is good though. Any thing that doesn't look right should be ground out and replaced.