The method I use for polishing has come about
through trial and error. There are several methods which essentially entail the
same steps.
-
Clean and degrease the component
-
Remove surface scores and pitting
-
Progressively polish the surface
It is easier to do the work if the components are removed, but still possible to do in
place on the bike.
Clean
& Degrease
I use Gunk or a propriety degreasing agent to remove the surface grease, having removed any caked
on layers of dirt, oil and grease with a wooden stick. The gunk is washed off to leave a
clean surface and can then be dried off with a piece of clean cloth.
Tip
from Burton
Bike Bits: A good biological
wash powder works just as well as a degreasing agent and is a lot cheaper.
You may want to try it and let me know.Tip
from Jim Downey: A
professional polishing shop gave me a good tip. We have a waterless hand
cleaner called 'fast orange' which has a little pumice in it. We clean
the part in the hand cleaner and it really gets all of the grease off and
some of the oxide. It is great for getting the part grease free in a
hurry.
Remove
Surface scores and pitting
There are two ways of achieving this.
-
Manually using Emery paper
-
Abrasive Wheels
On aluminum I prefer to do this manually using emery paper, starting with a coarse
grade to remove the larger abrasions. This is best done by concentrating on about an inch
circle and progressively working outwards with overlapping areas. Try to avoid putting
scores into the surface of the metal. Following the same method I use a medium grade
paper, and then repeat this with a fine grade paper.
Alternatively you can use abrasive wheels, which consist of cloth (rag) wheels onto
which you put abrasive paste. The paste comes in the form of sticks which is deposited
onto the wheels and then they are allowed to cool off hardening the adhesive. The
process of polishing is similar to above applying the wheel in different
directions for each grade and not applying too much pressure which generates heat and
causes the abrasive to come off the wheel.
Tip
from Jim Downey: Polishing
aluminum is not difficult but it does require significant elbow grease.
The trick is to water-sand all parts with 400 paper until bright. The
sanding removes the hard oxide coating. Unless the oxide is removed no
amount of buffing will cut through it.
Polishing
Once all the pitting has been removed it is a case of
polishing, and this is where the buffing wheels come into there own. You
can sit there with a tube of metal polish and a clothe, but it is long,
hard work. Again using clothe wheels, you apply polish sparingly, and then
progress to polish the area, this is repeated with a finer grade of polish
and results in a mirror finish. Any imperfections from the previous stage
will now show through, and you may have to go back if they do.
Finally, use a proprietary metal polish & clothe to bring out the
best lasting shine. Remember that aluminum is porous and some coats of wax
polish will help to seal it.
Safety
Always wear a face mask, as the fine metal and dirt particles will lead to
chest problems over a period of time. Safety glasses are also essential, as
it is nice to be able to see what a good job you have done afterward. Remember,
blindness is permanent and at best you will have very sore eyes for days.
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