Dominique Deresmes asked what the coating is that's on the cast aluminum
side windshield posts of an MGB roadster.
I faced this question some years ago and asked it at several metal treating
shops, including one that served the aerospace industry and did very fancy
work. Although there was no concensus, the most common guess was that it
was something called "Bright Dip", but I was told this process was no
longer available, at least in California, because of environmental
regulations. However, it was said to be very similar to clear anodizing of
a polished surface - in fact, no one could explain to my satisfaction how
it differed from the latter.
I had my posts lightly ground, as required to remove pits, then highly
polished and clear anodized. They looked beautiful and original - and have
remained so for eight years now. If this is not the same as the factory
process, it must be very close.
A word of caution: although the anodizing will create a
diffusely-reflecting surface, achieving a high luster in the polishing step
is critical to the finished appearance. Before it is anodized, the
aluminum should look like it was freshly chromed. This takes some serious
buffing, as the original anodizing, which is very hard, must be completely
removed. I did a small spot with my Sears buffer then turned it over to
the pros.
Russ Wilson
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