Hi

A newbie to trailers here, but been around airplanes a while.

I do not have any vested interest in polish companies or products, or clearcoat companies or products.

Natural unprotected aluminum develops a layer of aluminum oxide on it - it rusts! But unlike steel rust, aluminum rust protects the aluminum from further oxidation. It is self healing, which means any scratches will oxidize and protect the rest of the aluminum under it. It will last forever - well, almost. It is very tuff - they make sandpaper abrasive out of aluminum oxide.

It looks cloudy. People usually do not like this cloudy look, so they want to make it look better.

Corrosion can occur when some chemicals attack the aluminum, or occasionally its oxide. Corroded aluminum has no strength or mechanical integrity, so corroded aluminum things will fall apart. NOT a good thing to happen to your trailer on the road.

Corrosion often gets bad when a corrosive chemical gets trapped under what should be a tuff protective coating, like clearcoat, paint, etc. and finds a home there. Filiform corrosion is one such corrosion. The corrosion products take up more volume than the aluminum it eats, often lifting up the coating forming bumps; it may have a wormy appearance.

Look at your aluminum gadgets - plane, trailer, whatever and if you see such corrosion, do something about it now before it gets to be a real problem.

We have a lot of corrosive chemicals in the air, and even water, nowadays so such corrosion needs to be fought.

This corrosion can start immediately on unprotected aluminum, so how do you protect it? (the aluminum, not the corrosion... the corrosion can take care of itself :-)

If you like a funny yellow there are aviation (read expensive) primers. DOW makes an Alumiprep product pair that works very well, but it looks funny too. Both work. Both can be left as the only protection on unpainted aluminum, but usually primed aluminum parts get painted if people can normally see them.

Most airplanes have aluminum skins. Very few of them depend on polish or clearcoat to protect the aluminum. They use paint. Good paint on a real clean surface. It works.

But Airstream owners do not like paint, because they like the aluminum look, so we are left with polish or clearcoat - both have advantages and disadvantages.

Both surfaces benefit from frequent cleanings.

PROS & CONS:

POLISH -
a LOT OF WORK, that must be REPEATED FREQUENTLY, but it sure gives a shiny mirror like finish. (Telescopes can use polished aluminum as a reflector.)
Note: It is expensive to reapply clearcoat again once removed for polishing, so make sure you have what it takes to keep on polishing before you remove the clearcoat.
Remember the words "work", and "repeated". How much money, sweat, time do you have? :-)

CLEARCOAT -
is a tuff polymer (read plastic) coating, and will last a REAL long time. If the precoating preparation was done well ( <==NOTE THIS WELL).
If not scratched or abraded ( mechanically or chemically) it will last a long time - like many years - but eventually the scratches, etc. remove enuf coating for corrosive chemicals to start their evil work.

UV sunlight has lots of energy in its little photons, which can alter the polymers in the clearcoat, so UV protection is also important, another reason for a good sealer.

Clearcoat degradation and the ensuing corrosion can be delayed a long time by sealers, touchup work on scratches, keeping it clean of chemical irritants, etc. This is a much smaller amount of work ,sweat, $$$ than polishing.

Clearcoat is not as shiny looking as polished aluminum, but it requires a heck of a lot less work, sweat, $$ ...we are not as shiny looking as we would like to be either :-)

remember the words "less work" "less $$" "less sweat"

as Roy used to say,
"happy trails"

Darrell Kachilla
71 Sovreign rebuild project