Thread: Identifying Aluminium

Originally Posted by Oldneweng

What you would have created here is soldering fluid. Another thing I did not think of until reminded. What is happenning to my brain? Don't answer.

Dean

"killed spirits" if I recall correctly

Originally Posted by eskimo

"killed spirits" if I recall correctly

Thats the one! I knew the "killed" part but could not remember the "spirits" part!

Dean

I always thought that you can tell aluminium with a magnet it wont pick it up,


Eddie

Austenitic grades of stainless steel are also non-magnetic.

Originally Posted by TKO

I always thought that you can tell aluminium with a magnet it wont pick it up, Eddie

It's not a good test because most metals are nonmagnetic.

A really neat way to test for Al is using Bromoform because Al will float in it whereas almost all other metals will not.
To discriminate between Al and Mg the heavy liquid to use is Dibromomethane , Mg floats but Al sinks.
Unfortunately these chemicals a pretty toxic so you need a fume hood to handle them

BobL beat me to it, TKO, aluminium, zinc, tin, magnesium, titanium and many many other metals look alike and none of them are magnetic. In fact only iron and nickel containing metal alloys CAN be magnetic (if I remember correctly).

Thanks for putting me right on the methods ,I always thought that the magnetic test was the way to go,the photo above is a variety of off cuts given to me the other day,and those marked are not magnetic the bright steel looking ones are I think Stainless steel, and not magnetic they have rust which I think is because they have been stored with the rusty steel for many years and it wipes clean with a cloth, the Brass pieces are two inch in dia and the large round pieces are aluminium, I can't tell if the brass pieces are bronze or brass, I have several other longish shafts in molasses up to 2 1/2inchs in dia,,some are very tough and most are mild steel, the oblong piece of steel is 3 x3 x5/1/2 inches, could make some nice big nuts, I'm learning still.

Thanks Eddie.

Originally Posted by TKO

Snip

Thanks for putting me right on the methods ,I always thought that the magnetic test was the way to go,the photo above is a variety of off cuts given to me the other day,and those marked are not magnetic the bright steel looking ones are I think Stainless steel, and not magnetic they have rust which I think is because they have been stored with the rusty steel for many years and it wipes clean with a cloth, the Brass pieces are two inch in dia and the large round pieces are aluminium, I can't tell if the brass pieces are bronze or brass, I have several other longish shafts in molasses up to 2 1/2inchs in dia,,some are very tough and most are mild steel, the oblong piece of steel is 3 x3 x5/1/2 inches, could make some nice big nuts, I'm learning still.

Thanks Eddie.

Some stainless steel is magnetic, some isn't. Depends on the grade. When induction hardening many years ago we had to use SS hose clamps to avoid them heating up and melting the hoses. I was surprised to be asked to harden a SS piece. Another learning experience. I pick up lots of SS and other fasteners at work, left on the ground etc. I use a magnet sometimes as a check with these when sorting. SS can be stained with rust from other pieces but it will not rust. It oxidises and this oxidation looks like rust but it is not. Mostly cosmetic, except in the food industry. Hence the need to pickle it after welding etc.

I am hopeless when it comes to brass, bronze etc. I have not had a lot to do with anything but brass and copper.

Dean