Humm...
I've used DP over 1790 etch prime, and it works just fine. There's a sealer
that you can use over unknown base coats- and I've used DP diluted as a sealer,
also with moderate success... the secret seems to be to seal the filler and
primer/filler after it's sanded. Which increases orange peel, but reduces
'bleed' from the base substances. It's all a trade- off.
Mixing systems (PPG and POR) is always a crapshoot- if you know what you're
doing, you can often get away with it. But if you're wrong, you end up with a
sticky mess. My take would be to go with PPG all the way- maybe not the best
in the universe, but very good, and guaranteed to be compatible with itself!
As to how to deal with the POR- I think I'd sand it off. I know it's not good,
but a metal- adhesion layer problem will kill the whole paint job quicker than
you can say "GM water based topcoat".
hth,
Toby
> Group,
>
> I've been an active reader of Auto Restorer for several years and have
> been following their restoration tips from stripping the car clean to
> clear coating the paint. To date I have completely stripped the car,
> sandblasted the body and frame, cleaned, etched the metal and applied
> POR-15 to everything but the exterior. I purchased PPG epoxy primer to
> use as a base coating over the exterior metal. The problem I face is
> that PPG states that epoxy primer MUST NOT be applied over an etching
> primer. It will bubble up and just not stick. POR-15 makes an etching
> primer to be applied directly over the POR-15 as base coat primer. My
> question is, has anyone applied an epoxy primer directly over POR-15? If
> indeed I can't apply epoxy primer directly over the POR-15, I will be
> forced to use two different types of primer and paint, one type for the
> POR-15 areas and epoxy primer on the exterior surfaces. I hope I'm not
> boring the group with this long question.
>
> Thanks
>
> Steve Harvey
> Milwaukee
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