On 7/30/2017 4:00 AM, John B. wrote:

I've got quite a few aluminum bits and pieces from older bikes that
are pretty shoddy looking with nicks and dents and corrosion. I can
clean them up with a "flap" wheel and then polish then with the
usually buffing wheels and decreasing compound grits until they have a
high polish but once back on a bicycle again they seem to corrode
rather rapidly and in a few months end up looking sort of "splotched"
and dull, which of course is exactly what bare aluminum does in
contact with air.

I've tried a number of schemes to preserve the polish such as heavy
paste wax and even a coat of clear lacquer or in one case thinned
epoxy resin. This wasn't exactly successful as the wax disappears
quickly and the lacquer tends to chip and even the thinned epoxy tends
to flaked off in places.

Shimano seems to coat much of their aluminum bits with some sort of
"silver paint" which obviously isn't just that as it seems to last for
years.

I would prefer the look of highly polished aluminum (without the
corrosion) but that obviously will take considerable and continued
labour the way I am doing it at present.

Does anyone have any suggestions on how, or with what, to coat highly
polished aluminum to, at least, reduce the corrosion to a reasonable
level? Say a once a year polish?


Classic French equipment in bare aluminum looks fantastic
with Simichrome or any similar metal polish on a cotton
cloth. Trouble is, as we both found, regular cleaning and
polishing is required to maintain that finish.
http://www.yellowjersey.org/photosfr...st/mikipv9.jpg

Campagnolo classic cranks had a deep clear anodize which is
more durable but an absolute pain once nicked through.
Filing out the damage followed up with wet sand and then
rouge on a cotton wheel leaves a 'hole' in the finish and so
you're back to the prior paragraph.

If you can accept painted rather than metal aesthetically,
consult your local auto paint supplier - the guy who sells
to body shops. Metal etch and two-part primer for aluminum
are standard items, after which a silver[1] metallic
catalyzed paint could roughly duplicate the modern Alivio
type finish.

[1] or pink, whatever.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971