Re: [A/S] Polishing woes possibilities

["argosy24mh"]

I have to agree with Roy. The cladding is just that, cladding. The 
skin is only 50 thousandths of an inch thick, it doesn't make 
sense the cladding would be more than a few thousandths. I 
sincerely doubt Airstream engineers foresaw the polishing craze 
in the 60's and spec'd their coils with a .010 clad layer. Because 
cladding is very hard, a thick layer would dramatically stiffen the 
panel, making assembly more difficult. They had what they 
wanted with a normal thickness cladding, easy assembly and a 
bright exterior surface.

Pure aluminum is very soft. Silicon, copper, and other metals are 
added to harden it. That is what the cladding layer is, harder 
aluminum. Harder metal will polish better than soft, not as much 
tearout from the abrasive, so a smoother surface. How many 
times has this been polished in 40 years? Did someone get 
agressive trying to remove a scratch? How much did they know 
about polishing, it takes a light touch, slow speed buffer, and a 
very fine abrasive. It is very easy to cut through a clad layer, and 
the softer metal beneath doesn't polish the same.

John