Try a magnet on it...
Jim

On Fri, Apr 18, 2008 at 8:30 PM, Kim Brennan <kimbrennan@mac.com> wrote:

> I took the clamshell spare tire holder off a couple of my vans and one
> of them has been sitting outside ever since.
>
> And not rusting.
>
> Which makes me curious. What is it made of? I can't imagine that it is
> aluminum. Seems way too thin for that. yet it's not standard steel, as
> the bare metal would have rusted a long time ago.
>
> It's relatively light weight, but also fairly thin.
>
> A wandering mind on a Fryday wants to know.
>