Autosol is a chrome polish, so it's a very hard abrasive. It'll work on aluminium, but it's a lot more effort than you need. Using a coarser and softer polish will get you there much more quickly.
Don't use Brasso. Unless you clean it carefully afterwards, you can get discolouring, because of the ammonia in it.
Not in practical terms. Aluminium takes hours or days to form an appreciable oxide coat, and even then it's pretty negligible. Ti in contrast is far more reactive and you can watch the oxide film form in seconds. If your aluminium has an oxide coat that you can mechanically notice, it got there by anodising, either deliberately or as a side-effect of heat treatment or pickling.
And "aluminium oxide" covers a range of materials, where the mechanics depend on the crystallography, not just the chemistry. Comparing the stuff found on a sheet of aluminium metal to corundum is ridiculous. And it will never be "ruby" or "sapphire" unless you start doping it.
Andy Dingley wrote: (about polishing aluminium)
Rubbish, total ablls, Brasso is a good polish for aluminium (also Perspex, etc). Google "brasso aluminium".
Well, duh.
Well done.
While it will work on aluminium (as long as you wash it afterwards to avoid discolouration), it is not in any way a good polish for perspex - it will leave a very cloudy surface. Try it.
I have tried it, on 1/2" Perspex. It works well. A better result is had using Perspex polish No. 2 afterward. Perspex polish No. 1 is very gritty (some yrs ago, perhaps No. 1 & No. 2 are the wrong way around). Perhaps you were thinking of something other than "Perspex"? Brasso is also good on resin castings.
N.B. if you polish aluminium off properly, or even polish reasonably frequently with Brasso there's no problem with "discolouration".
Oh - is THAT what does it! I should have realised ... Brasso is certainly not effective in polishing Al but I don't know what is in a household/workshop situation.
Mary
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Damn. My 'A' level chemistry master was lying. I wonder why?
Eh? Have they changed the formulation? It certainly used to work ok.
Brasso is a soft tripoli in a liquid medium. Tripoli is an appropriate polishing medium for soft metals like aluminium and is pretty good for some harder plastics too. It won't make a dent in chrome though, hence the existence of Solvol Autosol. However the choice of liquid for Brasso is chosen for cuprous metals, and it's not a good choice for aluminium of plastics.
In particular, it's hard to polish plastics with a liquid medium and a standard mop. You're much better off with a paste medium. A hard mop is too likely to burn the surface on plastics, unless you arrange a lapping machine.
As you know everything about everything, perhaps you'd like to explain to us _why_ Brasso uses ammonia, and why this is an irrelevance (and potentially a harmfully discolouring one) for aluminium.
Actually about a day after you polish it, a new oxide layer forms. Its a bit of a watse of time really.
The short amnswer is the oxide is so thin that it doesn't impede reflection.
However its not scratchproof at all.
All pure and semi pure forms of aluminium suffer the same fate. It is only the exotic alloys that can remain reflective.
I worked in the aerospace industry for nearly 30 years and the only mil jet that was polished was the lightning and for the life of me, I can't remember what polish was used. It was never like a mirror, but it did make a big difference to its appearance though.
Dave
It used to have some form of alcohol base? as I've seen 'unfortunates' drinking it. Although this was in Balham. They drink anything here.
'Twas my understanding it oxidised very quickly which is why it's difficult to weld or solder.
You mean on perspex? Dunno if they've changed the formulation, but I tried to polish out some scratches on a piece of clear perspex a few years ago and ended up with a very cloudy surface.
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