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
--

Enoch Root wrote:

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


I bought some material at the local metal supplier that was rolled to a
mirror
finish. It is easy to scratch it, but the completed parts have retained
their
finish for something like 8 years so far. I don't know how this is
done, I'm
sure there is some kind of a passivating coating applied when it is made.
A blue plastic film is applied to the mirror side, and you peel that off
after the piece is cut, drilled, etc. The sheet had no markings on it that
I remember, so I have no idea what alloy, manufacturer, etc. it was.

Jon

Bright dipping is used to make aluminum trim shiny and not oxidize.

"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
--

"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.

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

Enoch Root wrote:

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
--

I found this piece that gives a brief description of the Alzak tm
process and also some interesting aluminum spinning info:

http://www.cooperlighting.com/brands.../adi020467.pdf

It must be top secret though as I can't find a single reference on the
ALCOA site and it's their trademarked process.

Pete C.

Jon Elson wrote:
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


I suppose a wax-based polisher would interfere with any chemical attempt
to protect the finish... unless it was done *after*.

Wow, lots of good info. Thanks to everyone.

er
--

Enoch Root wrote:
I suppose a wax-based polisher would interfere with any chemical attempt
to protect the finish... unless it was done *after*.

My experience is that the wax film left on the aluminum is pretty
durable, and the polishing only needs one touch-up a year, if that.

Jon