not sure what forum to put this in for best results but.. could somebody please tell me which is the correct order when bare metal is exposed. I've read people saying both, but i'm looking for reasons why, hopefully from experts.

etch prime first and use the filler over the primer

OR

use the filler on the bare metal first and etch prime after to cover the remaining bare steel

ALSO

is it necessary to sand right dowen to the metal when fixing a dent? can the bondo stick to scuffed up paint ok? is one way more or less durable than the other?

thanks

d

 

filler is always over bare metal

 

thanks, here's what i've done based on what i've researched for anyone looking to know.

the conflict i was having was my diy book said to bondo on the bare metal, so did most people in my research. that would seem to make the etch primer redundant eh?

but others said its good to put some kind of sealer or protection on the metal first, then bondo over that. As bondo (filler) is porous and provides no protection.

But in further research, i found that bondo over etch primer is a no no, as this primer contains acids that may cause the bondo to lift. But, there are "some" etch primers that say its ok to bondo over it.

Soooo, here's what i decided to do...

1 bondo right on the bare steel
2 block sand it down
3 etch prime the bare metal spots that showed up (as regular old primer won't stick to metal apparently)
4 regular prime the over it all (i have dupont acrylic laquer primer)
5 spray a guide coat of a different colour and wick sand off the high spots
6 glazing compound for any scratches (then more primer)
7 paint

...and of course wax and grease remover btw every step.

its been going pretty good so far. i've got most of the dents filled and primed. Just one bad spot where there was a crease and the metal popped through in my sanding. i'll have to hammer it down and refill.

i've found that when block sanding, as soon as metal pokes through, your done. The metal won't sand down further, only the surrounding bondo will get lower. so if there's any low spots that i didn't hit with the block sanding, i've got to knock the metal in a bit and start over.

one other thing, does that etch primer ever stick. trying to get it off is like trying to get rust off, either sandblast or sand down through a layer of metal.

d