Questions About Pot Construction

[Shel_B]

Being a curious fellow, I was wondering how the aluminum or copper disks are attached to the bottoms of various pans. Is there more than one method? Is any method considered better or more durable? Are different techniques used depending on the pan material?

Also, are different techniques used for bonding the plies together on different brands of cookware. Several brands use three, five, or even seven ply construction, like All Clad, Calphalon, Viking ... are they all manufactured the same way or do some manufacturers use different techniques? Is any one technique considered better or more durable?

Is 18/10 stainless more durable than 18/8 stainless?

Shel

Edited October 6, 2007 by Shel_B (log)

[budrichard]

Most pots/pans are punched in a press out of disk of the material. I assume that the various layers are bonded by high pressure at high temperatures. An episode of 'Made in America' visited the AllClad factory if I remember correctly.-Dick

Edited October 7, 2007 by budrichard (log)

[tim]

Shel,

I assume there are various methods to bond metals together.

All-Clad Metallcrafters had a patent on their bonding process. Falk Culinar develop the process to bond stainless linings to copper pans. Spring cookware, from Switzerland was also very early in having a tri-ply product.

Tim

[paulraphael]

I've been curious about this too. Seems impressive that you can stick together metals with wildly different thermal expansion coefficients, repeatedly heat them to 500 degrees and quench them in water, and not have things warping and flying apart.

I find it especially curious that my clad pans (aluminum encased in stainless or stainless bonded to copper) seem impervious to warping, while my all-aluminum pans warp prettty easily.

[slkinsey]

I find it especially curious that my clad pans (aluminum encased in stainless or stainless bonded to copper) seem impervious to warping, while my all-aluminum pans warp prettty easily.

Unlined aluminum cookware for home cooks is rarely manufactured at a sufficiently heavy gauge to avoid warping. There are some professional lines at >5 mm that I imagine don't warp.

Anyway, the stainless lining does seem to provide some kind of structural integrity that helps to prevent warping in clad aluminum cookware.

[tim]

I find it especially curious that my clad pans (aluminum encased in stainless or stainless bonded to copper) seem impervious to warping, while my all-aluminum pans warp prettty easily.

Unlined aluminum cookware for home cooks is rarely manufactured at a sufficiently heavy gauge to avoid warping. There are some professional lines at >5 mm that I imagine don't warp.

Anyway, the stainless lining does seem to provide some kind of structural integrity that helps to prevent warping in clad aluminum cookware.

←

Hi,

Conversely, a 2.5 mm aluminum roasting pan does not warp while All-Clad's Stainless roasting pan does warp.

Tim

[slkinsey]

As the owner of both a heavy anodized aluminum roasting pan and an All-Clad Stainless roasting pan dating fom the days when they actually had an aluminum core in their Stainless roasting pans (they no longer do), that is the opposite of my experience: The anodized aluminum roasting pan warps, the stainless-clad aluminum pan does not.

[paulraphael]

my calphalon cookware is 5mm thick, and the pieces i've used on high heat have warped. some of them i've pounded back into shape with a hammer to get them to sit flat on a burner!

[budrichard]

All of our Calphalon warped. We threw it out when I purchased Falk.

As far as I could tell Calphalon contruction was just a cheap way to manufacture a pot and then anodize to resist sticking.

The thermal coefficient of expansion of copper and stainless steel is just about the same with aluminum about 30% higher. Why Calphalon warps, I don't know. I wonder if the manufacturing process results in different hardness of the aluminum in different areas of the pan?-Dick