Andy Cost wrote
>Media, sand, bicarbonate blasting seems like a good idea but it has
>drawbacks too. It is very easy to warp the panels with blasting. It
>doesn't remove rust. Rust forms pits in the steel. When you blast the
>steel it removes a lot of the rust, but it also folds the edges of the pits
>over. What you end up with is a very smooth looking rust free part. When
>you put it under the microscope there is still rust living down in the pores
>and covered over pits. The only way to get it out completely is immersion.
>My bet is that the parts that you had blasted will form rust bubbles under
>the paint within ten years.
There is truth to this, but I think the peening-over-rust dangers of
sandblasting are overstated. Of course a dipping place will tell you
blasting will ruin your car, and a blasting place will tell you dipping
will ruin your car. The truth is probably somewhere in-between. A well
sandblasted part which is well prepped and painted will probably last
well. Rust needs oxygen, so even if there is some rust you can
significantly slow it with good prep and paint. Significantly slow it to
the point of nothaving to worry about it. There's still te warping
danger of blasting but doen't this apply mainly to flat panels?
I do have some rust on my car, but it looks like Bondo and dirt
between panels where paint and sealer didn't get are the culprits. Paint
was removed abrasively in that case.
-Marc T.
==========================================================================
Marc Tyler TDROC Sisterdale TX
1970 1600 #SPL311-31016
1965 L-320 #L320 013642
http://datsun_marc.tripod.com/cgi-bin/datsun_homepage.html
/// datsun-roadsters@autox.team.net mailing list
|