James Silverton wrote:
>
> Hello, yetanotherBob!
> You wrote on Fri, 5 Jan 2007 09:57:37 -0500:
>
> y> In article
> y> >,
> y> says...
> ??>> nother question.. in what way did they change and how long
> ??>> did it take them to do so?
>
> y> The one small (about 1 qt.) Calphalon saucepan that we had
> y> started flaking off its finish around the lip of the pan and
> y> around the rivets on the inside of the pan after only one
> y> run through the Whirlpool dishwasher we used to have. It
> y> was only downhill from there. It looked positively leprotic
> y> after a couple more runs through the Whirlpool, whereupon we
> y> tossed it.
>
> I think damage to anodized (hard oxidized) aluminum in a
> dishwasher is probably due to the highly alkaline nature of some
> dishwasher soaps which will dissolve aluminum oxide if only
> slowly.
Yes, the highly alkaline dishwasher detergents will strip the anodizing
over time. Add in moderately alkaline water to begin with and the
anodizing doesn't stand a chance in the dishwasher.
The thing to remember of course is that there is plenty of non anodized
cookware out there and in use which works just fine. Indeed the aluminum
self anodizes to some extent, forming a protective aluminum oxide layer.
The main loss that you get when you dishwasher hard anodized Calphalon
is the loss of the extra hard surface so the resulting pan, while
perfectly safe and useable, will scratch more easily.
On my little anodizing line you use sodium hydroxide (lye) to etch the
aluminum before anodizing and also for a longer period to strip old
anodizing if you want to reanodize and dye a different color.
> Calphalon used to sell a slightly abrasive cleaner for
> the pots which would remove persistent deposits if not
> accidentally burned-on grease. I haven't seen the cleaner in a
> while but it's no great loss since Bon-Ami cleaner seems to work
> as well.
Dormond. Works pretty well.
>
> Incidentally, it's an observable fact that you *can* scratch
> Calphalon pots with utensils :-(
Yes, hard anodizing is, well, hard, but like anything else it is not
indestructible.
Pete C.