In one of the many responses I received re: BJ8 Nuts and Bolts, one
suggested Cad plating. Not knowing Cad Plating from Chrome Plating I
searched the Web only to find Pandora's Box out there. I have read some
pro's and con's regarding Cad vs. Tin (Mostly environment issues). There
was also the issue of doing it yourself (Caswell's, Eastwood, Etc.) as
opposed to sending it off to a shop. Can the list give me some guidance or
web sites that can assist me in my research. Thanks.
Gary in Yucaipa, CA
Dear Gary, here's the thing.
Zinc is an electrolytic plating, it's a
sacrificial plating, just like Cadmium is. The
metal part, say a bolt, is first etched in acid,
then wired for electric current, then it's plated
in an electrolytic solution, where particles of
an anode (zinc or another metal) are drawn
through the solution to the negatively charged
bolt which becomes plated with these metal
particles, then rinsed off. Voil` zinc plating.
The plating is meant to rust first, so the bolt
is protected somewhat from corrosion.
Cadmium is usually a gold-green plating, it
sometimes has red or blue streaks. There are
different types of cadmium plating, you'll have
to speak to your local plating house; ask to see
samples. In terms of protection, Cadmium is
slightly better than zinc, it's used on high
grade bolts and most modern car parts these days.
There are other coatings for metal, notably black
oxide and anodizing and bright-dip, which were
used on Healeys and you would have to restore.
As for chrome same as above, but it's a multiple
metal plating with polishing between plated
layers of copper, nickel, chrome. It's more of an
art than Cad or Zinc to plate chrome, so expect
to pay more for labor. Hard Chrome is used on
engine parts for durability, it's a single layer
of chrome. Some plating houses do all these
coatings and more, there are minimum charges, but
you can bring your bolts to them and get them
done.
Any sandblasting sanding or metal brushing
destroys these coatings, so you have to replate
everything when restoring your car. Hope this
helps.
--
Alain Giguere
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