Cleaning aluminium

I was dreading getting all the oxidisation off my horn loudspeaker, after a bit of googling I found the answer, soak in sodium hydroxide solution (500g to a few gallons worked for me). Result, all the crud had gone in about 20 minutes. Don't leave for too long it will dissolve the lot in the end.

[Herald1360]

A caustic dip also works wonders at cleaning off finger marks and other oily mess after you've "bashed the chassis". It'll also clean off (dissolve away) anodising if you need to make anodised ally make electrical contact with something.

It's pretty good on grill pans and other assorted paraphernalia with burnt on grease too!

[Mike Phelan]

Most dishwasher detergents have some sodium carbonate (washing soda) in them; that does tend to revert to sodium hydroxide.
Sticking ally parts in the dishwasher really cleans them up.

[Herald1360]

I'll second that. Some of our old ally saucepans come out of the dishwasher looking newly etched each time.....

[SeanStevens]

Originally Posted by Herald1360

I'll second that. Some of our old ally saucepans come out of the dishwasher looking newly etched each time.....

D A N G E R

Aluminium is not good for you and should not be injested. Getting aluminium very clean and then, say cooking something acidic in that pan will leach metal from the surface.

Choose enamelled pots and pans for cooking acidic items - Aluminuim pans for pasta!


SEAN

[newlite4]

Just like in your avatar Sean, "these are dangerous times"
Neil

[Mike Phelan]

Just as bad as trying to cook in a speaker, which I think was the original question asked!

Aluminium oxidises in a few minutes.

[murphyv310]

No doubt you have all seen my exploits with the pressure washer.
I use TFR (Traffic Film Remover) along with it, most TFR's are caustic and although the result is excellent on Alloy, the trick though is proper rinsing as the reaction can still continue in damp conditions.
A 25 litre tub of TFR will cost you about £25 and can be diluted and brushed on so a tub of that size should last a long time.
Yes it can be used for greasy pans too, but, rinse rinse and rinse with clean water after.

[dseymo1]

Aluminium oxidises in a few minutes.

Apparently, pure aluminium is flammable. The fact that pans don't burst into flames when in use is due to the surface oxide layer.
That (and its thermal expansion coefficient) is what makes ali so difficult to solder.

[trabant]

In responce to the TFR thing i generally use TFR followed by alloy wheel cleaning acid which brings things up exceptionally sparkly .
perks of working next door to a car wash

[richrussell]

I used alloy wheel cleaning acid on some 1930s brass light switch backplates that had corroded and gone green. Mainly because I had an alloy wheel cleaning kit in my garage from the days when I cared about what my cars looked like (these days, as long as the windows, lights and number plates are clear, I couldn't care less about the rest).

So I poured some into a shallow dish and sat the brass plate in it. Gave it a brush every few minutes to shift the dirt. At first it worked a treat - giving me shiny brass. Then shiny copper So I removed it from the dish and rinsed it - and the copper came off too. It seems it was made from brass, plated with copper, then plated with shiny brass. The acid too off both plating layers in about 10 minutes. I guess the moral of the story is - make sure you know what you're cleaning is made of!

On aluminium though, it works beautifully - just brush it on and agitate a bit, leave for 5 minutes then wash off. Leaves it very shiny and clean.

[ppppenguin]

Not sure where I read this but doesn't alloy wheel cleaning acid contain hydrofluoric acid? This is very nasty stuff. Although it's technically a weak acid its biological effects are extremely unpleasant. http://en.wikipedia.org/wiki/Hydrofluoric_acid

[Boom]

Originally Posted by Mike Phelan

Most dishwasher detergents have some sodium carbonate (washing soda) in them; that does tend to revert to sodium hydroxide.
Sticking ally parts in the dishwasher really cleans them up.

LOL - It would have to be a very big dishwasher to get a horn loudspeaker in.

Not in bits!

[Dave Moll]

Originally Posted by richrussell

I poured some [cleaning acid] into a shallow dish and sat the brass plate in it. Gave it a brush every few minutes to shift the dirt. At first it worked a treat - giving me shiny brass. Then shiny copper So I removed it from the dish and rinsed it - and the copper came off too. It seems it was made from brass, plated with copper, then plated with shiny brass.

Or is it more that the acid dissolves the zinc from the brass, leaving a layer of (insoluble) copper. Presumably, this rinses off in turn because it is no longer bonded to the rest of the brass - though I'm surprised that it simply rinses off, my experience being that a vigorous rub with the likes of Brasso is necessary to restore the brassy finish after the acid bath (though I have used the less-aggressive acetic acid (vinegar) for my brass cleaning).

Anyway, this is probably far enough to stroll down this coppery byway, given that the thread is about cleaning aluminium, not copper alloys.