On 6/30/13 6:35 PM, John Kuthe wrote:
> On Sun, 30 Jun 2013 16:17:14 -0400, j Burns >
> wrote:
> ...
>> Presto says their aluminum models have better cooking properties than
>> their stainless models at twice the price. The advantage to stainless
>> is that you can keep it shiny indefinitely. I've read that cream of
>> tartar will shine aluminum cookware. Is that the best method?
>
> Why? Aluminum oxide is a protective free coating.
>
> John Kuthe...
>
I see your point. The 1939 model looks fine to me.

Polished aluminum has an emissivity of about 0.05. Aluminum oxide has
an emissivity of about 0.25. So if I kept the exterior polished, it
would hold heat a little better... but I probably wouldn't notice the
difference.