Polishing
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.