Hi Kye and AT,
In the anodising process of Ally, again a very diluted Sulphuric acid is used to strip off any previous anodising. I've never heard of Hydrochloric acid being used anywhere in the Aluminium processing department. It's really only used in the brass refreshing process if my memory serves me correctly. We had a Hydro bath next to the Pickle bath and it was always bypassed unless you had a brass component going down the plating line. Nitric Acid (now there's some lethal stuff) was also used as a quick brightener of brass or copper.
Cheers,
BB.
