Roy Lewallen wrote:

Mea culpa. I did indeed type "calcium carbonate", while of course
the "TSP substitute" - "washing soda" - is *sodium* carbonate. At
least I gave the correct formula. I apologize for the error. Yes,
I'm sure the "soda" is from sodium, as in "caustic soda" which is
sodium hydroxide (lye) and "baking soda", which is sodium
bicarbonate.

Roy Lewallen, W7EL

I've used washing soda in laundy. It is very alkaline, but I'm not
sure it would have much effect on aluminum.

Sodium hydroxide, NaOH, definitely eats aluminum. I use it in
various applications around the lab. Red Devil is no longer
available due to the meth heads, but I found a private Loblaws brand
that works just as good. The ingredients on the label are sodium
hydroxide, sodium silicate, and chlorine bleach.

You can tell the approximate strength by pouring a bit in a glass
and adding some canning salt. If the salt doesn't want to dissolve,
the solution is pretty much saturated at above 32%. Also, when you
first open it, you might notice a small wisp of condensation above
the lip, and a strong pungent smell.

If you let some dry on a glass surface, it is a bit difficult to
wash off with plain water, and has a soapy feel. If you add vinegar
to a dry portion, it instantly neutralizes the hydroxide to sodium
acetate and water. The equation is

CH3COOH(aq) + NaOH(aq) -- CH3COONa(aq) + H2O(l)

Of course, it should be stressed this stuff is very dangerous and
requires all the precautions for corrosive chemicals. As you know,
it will eat holes in your skin. It doesn't hurt much since it also
destroys the pain cells, but they take a long time to heal. Some
eyeglasses are made with a plastic that dissolves with NaOH. A few
drops in your eye can cause permanent blindess in seconds, so wear
protective glasses.

Good luck!

Regards,

Mike Monett