carl mciver wrote:
"Enoch Root" wrote in message
...
| Hi,
|
| Is there a combination of aluminum alloy and finishing technique that
| will provide a mirror like finish that will not degrade quickly when
| exposed?
|
| er

Any aircraft manufacturer or mechanic will tell you that soft aluminum
will polish out best. I've personally spent a weekend polishing a plane by
hand. Painful. There are power polishers, though. Mirror like finish that
will last just fine for months before a little touchup is required. Wipe it
really clean with a solvent that doesn't leave a film, then apply some
polishing compound and scrub in circles until you either pass out or get the
finish you want. Wipe clean with solvent soaked cloth (you can get pure
cotton cloths and stuff for aviation that are great for this.) The mirrors
inside the airplane are-get this- plastic with aluminum skin polished to a
great finish. Sometimes you can put on a thin plastic film by companies
like 3M that are made just for this type of application.
From my experience there is nothing you can put over the finish that
will shine like the polished aluminum, so its up to you what you define as a
mirror like finish.

The polishing compound IS the protective coating! It is full of
Carnauba wax, or some similar wax. That is a hard, dense wax that
is pretty durable. I can't imagine polishing an entire airplane by
hand! I worked on an 18' radar dish that was being re-purposed to
a solar concentrator. We got a big electric polisher, and ran it hard
until the aluminum got hot. (The idea is to get the wax quite hot,
when you smell the hot wax it is getting good.) When the wax is almost
liquid, it allows the greatest exposure of the fine abrasive in the
compound. You can start with Tripoli, then coarse rouge, and finally
fine polishing rouge. Once you get a spot hot, you just move along
with the buffer, making parallel passes, moving at maybe up to 2 feet
per minute.

Jon