Plastic Media Blasting

[Hirsch <Catenary@domain.elided>]

(Don't think this note ever made it to the Digest,
so I'm resending:)

I had my '66 GTV bead blasted about a week ago and have
a few comments about the process:

1) Unlike with sand blasting, which can damage (warp) a good
panel, plastic bead blasting is less aggressive and just removes
primarily paint and rust. It won't affect rubber molding, but
will glass, so the blaster will (or should) mask any glass
that's present. I had a few exposed instrument light bulbs
broken by the process. A chromed door handle was also damaged.
The handle was wrapped in a plastic bag. Where the handle was
wrapped in masking tape, it was unaffected, but where it was
only "protected" by the plastic bag, the chrome finish now
looks "frosted". The lesson here is to talk to the blaster
and protect what you need to.

2) Although it generally leaves any body filler on the car, it
will "rough up" the filler and may even be removed, based on
the blaster's enthusiasm. There was a lot of filler on the
GTV. I don't think it was due to accident damage as much
as applied at the factory to smooth out a rippled panel.

3) Bead blasting (like sand blasting) will blast holes in
panels weakened by rust, so it helps you decide which panels
need repair. It also shows you what body panels had been
previously replaced.

4) One problem with blasting the interior of the car is that the
media gets everywhere and fills up all conceivable cavities. And
for some reason the material is hard to vacuum up. This means that
unless you remove the rockers, etc., to clean up the material,
it's possible to end up with the material plugging up drain holes
and holding moisture, which is very undesireable.

Rich Hirsch

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