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Mirrored Finish/Chromed Aluminum
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I would like to have a mirrored finsish on many of the parts attatched to my
handlebars. I have replaced the satin finished aluminum brake and clutch
levers with a mirrored finished aluminum set. My bike is a '95 Honda Shadow
ACE1100. Many of these parts are unavailable in a mirrored finish such as
the clutch perch and front brake master cylinder. My question is what would
be involved in getting these parts to have a mirrored finish and what would
the results be. I would assume I would have to get a special polishing
wheel for my bench grinder along with compounds and various grades of fine
abrasive paper. I have a sandblaster available if this would help. I know
that there are five commonly used aluminum alloys in use and wonder as how
the actual alloy the part is made of will affect my result.
As I possibly dumb question side note, I assume that manufacturers who
describe their offerings as "chromed aluminum" are using a misnomer as the
part actually just has a mirrored finish from a polishing process that
results in a part that has a finish similar to a chromed steel part and that
there is no acutal electroplating involved. I know that this once could be
true for plastic parts until a chroming process was developed for plastic
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No, some manufacturers do chrome-plate aluminium, but for some reason it
doesn't adhere as well as it does to steel. Someone who knows about
metallurgy will tell you why.
I find that polishing is best for alloy, anyway.
I remember chromed plastic components from model kits in the 1960s.
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I remember them from Honda Runes.
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(ABS?).
Thanks for your answers and comments in advance.
Tom Haughton
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There is no such thing as 'a dumb question' Tom,
there maybe a dumb answer. Like this one.
Like The Older Gentleman, I think that polishing
is the way to go.
Sandblasting may be fine to begin with when the
part needs to be cleaned before polishing, but be
aware that sandblasting leaves a matte finish, which I
do like, but you don't.
And now from memory, dating some 40 years ago.
Alu itself is very soft, and unsuitable for
parts that can handle any stress. So what you
and I call Aluminum usually is Alu plus one
ore even more other metals.
What other metals are used depends on
a couple of things, such as the way the part
is produced.
If it is produced by drop forging, like my brake
lever seems to be, the alloy can be pretty stiff
and copper may be used in the alloy.
When the part is produced by the injection-molding
process, then in liquid form the alloy must flow
easy (like water) and thus something else
than copper (I can't remember it's name) will be
used for the alloy.
Injection-molded parts usually have a grayish
look, and the thinner the alloy had to be in the
production process, the more grayish it looks,
and the easier it breaks too.
Every pro has it's con.
Alu and copper are on the other end of
the range of 'noble' materials. If you take
a sheet of alu, cover it with some water,
and then lay on top of that a sheet of copper,
then you have created what is known as
a battery. If there is an electrical conductive
path (the places where alu and copper
are in metallic contact!) then a current will flow,
and the alu (being the less noble material) will
dissolve. Just as the zinc of the old fashioned
zinc-carbon dry battery 'eats away'.
On airplanes they used to clad stiff
alu-copper alloy sheets with pure alu (it was
named alclad). The thin pure alu surface
oxidizes very fast, like alu does) but the
oxide layer prevents deeper oxidizing because
it is not permeable. Apart from that, the
oxide is hard, and wear resistant, and
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