Aluminum, "Potmetal", or Stainless

This may qualify for stupid question of the week, but does anyone know how to tell if a part is cast from aluminum or pot metal?

How about aluminum vs. stainless stamped parts?

use a magnet. alum isn't magnetic.

A magnet will stick to most types of stainless trim.

I'll be Damned! tried a refrigerator magnet on on some stainless moldings on my Benz and it stuck.

Tried it on the door handles, exterior mirrors, and emblems on my Tradesman and it stuck to everything but the mirrors (JY pieces from 80's Chevy conversion van). Is the magnet just sticking to the nickle plating on the handles/emblems?

I'm sure the handles/emblems are "pot-metal".

Isn't pot-metal just a "generic" mix of aluminum w/ "tramp" alloys added in?

I tried a little aspirin-sized "super-magnet" on a cast gauge cluster housing (like the middle one shown below) I got at a JY , but it won't stick at all.


I couldn't think of any reason why mopar would cast it in aluminum instaead of "pot-metal" and it doesn't seem to want to polish up as easily as aluminum parts.

Could the housing just be really "high quality" potmetal w/enough aluminum to resist the magnet?

pot metal is inexpensive metal made from from a bunch of different metals but is made and cast at lower temps keeping cost way down compared to steel or aluminum. 'stainless' steel is steel made with alot more cromimum added to the batch making it resistant to oxidization (rust).