Dave Baker wrote:

wrote in message
...
Hi all,

I want to do some anodising, and I am trying to locate a source of
sulphuric acid. Battery acid would probably be the easiest way to get
hold of it, but all the car part places around me say that they aren't
allowed to stock it any more because it is a restricted substance.
Curiously, despite being restricted, I can still buy it mail order and
have it sent to me through the post (http://www.getgeared.co.uk/
acatalog/Battery_Acid_1_Litre.html)!

Battery acid is only about 33% sulphuric and 67% water. You're better off
buying the 97% proof stuff with a specific gravity of 1.84. You can dilute
that if required.

Bit of a word of caution to the OP about diluting conc sulphuric acid:
the act of hydration causes heat to be liberated - plenty of it. The
WRONG way to do this is to add water to acid, which can result in
almost instantaneous boiling and ejection of water and acid.

The accepted way - in my day - was to slowly add the acid to the
water, with plenty of stirring with e.g. a glass rod. Even so, the
solution will get warm. The OP will need to read up more on this.

Modern precautions would probably include a moon suit, licensed
premises, Building Control notification, Planning Permission,
certificated training, a Part P inspection, Environmental Health
clearance, a trained medical team on standby, a raid by anti-terrorist
police, and Social Services taking away your kids. Only joking.