On Tue, 15 Feb 1994, Paul Tonizzo, Finance& Ops. IM&T, DTN 631-7107 wrote:
> Thanks Ray,
>
> I didn't sandblast the aluminum parts. Is the rust neutralizing stuff I've
> seen worth anything? It will be real difficult to sand certain areas of the
> tub.
>
>
> Paul
Dear Paul,
I am convinced the only sure thing to do with rust is remove it. I can
see it would be tough to sand door jambs, inside the trunk, and such.
Those areas I think I would sandblast again. Once over very lightly
should do it.
I once experimented with a rust neutralizer (Duro, I think it was) on very
rusty patches on my son's ford. I used the rust neutralizer on one side
of the car, and sandblasted the scaly patches on the other. I actually
think rust neutralizer worked, where you could leave it undisturbed after
application. But I made the mistake of priming and sanding and painting
as usual after the neutralizer "turned the rust to a black impervious
coating." The trouble is the black coating sanded off the high spots,
exposing rust, which came through the paint as if I had never bothered.
The sandblasted side was fine. At least, it lasted as long as the Ford.
Sandblasting is horribly messy, and is ungood for exterior sheet metal.
You can really warp a flat or gently curved panel with a sandblaster if
you dwell in one spot, or apply too much pressure. But no way short of
dipping will do a better job of taking rust off and giving metal a "tooth"
that will hold paint. I have no experience with dipping, but I have heard
it is tough to be sure you have eliminated the solution from box sections
and lap joints.
I consider it a bit risky, but if you will be painting the car with
enamel, you could spray interior panels, inside the trunk, and inside the
engine compartment with rustoleum damp proof red primer, let it dry for
weeks, then apply enamel. Spray several 6 inch squares of clean sheet
metal with the primer at the same time, keep them with the car, and try
your enamel on one of them first, to make sure the primer has lost all of
its carrier and will not lift. But re-sandblasting to eliminate the rust
would be safer by far. You just do *not* want to restore this car and
find that paint starts peeling off of the engine compartment in a year.
Ray Gibbons
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