G'day Andy.
Before writing back on the Sodium Metabisulphate I did a quick Google
check as I also recalled it was metabisulsphite.
It seems they are interchangeable as sterilising agents. The
metabisulphite seems to be more hazardous.
I guess alum provides a good source of active sulphate ions to attack
the iron in the tap.
One good turn deserves another.
Regards.
Ian.
--- In 7x12minilathe@..., andrew franks <andyf1108@...>
wrote:
Hello Folks,
To be pedantic, I think that the sterilising stuff is sodium
metabisulphite (Na2 S2 O5), rather than metabisulphate, but I don't
suppose that would make any practical difference. I might also
experiment with sulphuric (battery) acid. When I made my first
attempts at anodising, it seemed to leave the aluminium alone (no
doubt because of the oxide layer), so maybe that would attack the
broken tap and not the aluminium alloy it was stuck in. I suppose an
initial rinse in solvent would help, by getting rid of any cutting
oil and allowing the chosen chemical to get at the steel.
Andy
