Which comes first? Por15 or Bondo/body filler?

[Kozworth]

Hey there,

I am currently shaving an engine bay, and I am getting to the point of putting some body filler into the ground down welds and whatnot.

On the por 15 can, it says apply to direct metal. On the bondo/body filler it says the same thing, sand down past primer/paint and apply to direct metal.

My question is, what do you guys use? I definately have a lot of spots to putty up, but do not want to have por 15 not stick to the putty, or the opposite, spray the por first and not have the bondo stay.

Thanks in advance!

[Poorboyz]

I'd call the makers of the POR-15. From what I've read on it I don't believe it will stick to bondo.

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[Swanny]

Spray por, scuff up, then putty?

[BimmerJeff]

I know it's common practice for hot rod guys to put filler over epoxy primer and then primer again. I'd contact POR directly and see if filler will stick to scuffed up POR.

[jeffnhiscars]

POR is a rust killer that should go on bare metal. I have also use it as a resin with fibreglass cloth to repair my wheel well (posted in my build thread) so I would be very surprised if bondo doesnt stick to it as long as its rough sanded so the bondo can bite to it

[Todd Black 88]

Why are you using por15?

If you have good clean metal, its unnecessary. Just clean the metal, apply filler, prime and paint. Just like all other body work.

If its rusty metal......fix it.

[audiquattrot]

Por15 on bondo isn't going to do anything. Like Todd said it needs to be applied on bare rusty metal

[Gertech]

If it's not rusty I wouldn't bother with the Por. Use a decent filler and prime everything with a dtm epoxy and you'll be good to go.