Nice post, but I'm not sure you're right on one minor point: Chuck wrote: <snip>
"A simple test to see if an aluminum part is anodized or not. Put a little dab of Semichrome (my personal favorite) on a white cloth and rub the part a little. If there is a black deposit on the cloth that means that there has been a chemical reaction with the aluminum. If the part is anodized, there will be no change in the polish on the cloth because there has been no reaction (and absolutely no damage to the anodizing)."
Chuck may be right, but my experience polishing brass (Junior ROTC, which I failed lo those decades ago) and other metals always led me to think that it isn't a chemical reaction that leads to the black deposit. I have always thought that it is just the appearance of the very fine particles removed by the abrasive Simichrome or equivalent. Grinds away (polishes) the bare metal, but softer than the anodized aluminum oxide, so no metal powder comes off. My memory is that brass cleaner has some ammonia, absent from cleaners for Al and silver, but the cloth rubbed on the metal winds up looking the same.
But, I'm not a chemist, and my elegant observations (!) could have led me to jump to a false confusion...
harvey "not often pedantic" sachs mcLean VA
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