How do you tell if its alum. or stainless,magnet wont stick to either.is there some way to test the stainless?

Question

How do you tell if its alum. or stainless,magnet wont stick to either.is there some way to test the stainless?

Answer 1

Weigh it.

Heat it up (different coefficients of thermal expansion).

Polish it. Aluminum tends to have a mirror finish, but stainless tends to have a VERY slightly tinted appearance(a result of the carbon IIRC).

Answer 2

Steel is both heavier and harder than aluminum.

Aluminum has a surface patina of oxide that steel lacks.

Answer 3

If possible, the easiest way to tell the difference is weight, steel weighs much more than aluminum.  If the objects are of similar size you would notice a significant difference in their weights when compared to each other.

Answer 4

The steel is ~ 3 times the density of aluminum.