"Norman Billingham" wrote in message
...

wrote in message
ups.com...
Hi

I plan to use HCl on a shower head - dont know what kind of plastic it
is though, makes it hard to look up whether it'll be happy with the
HCl. Any ideas?


If all you want to do is descale it then dilute (say 5%) HCl will not
attack
any likely plastic, but keep it well away from any plated parts - it will
dissolve chromium or aluminium. On the other hand, kettle descaler wil
also
work and is a lot safer.


Polypropylene was the pipe material of choice for concentrated (36%) HCl and
many other acids in the process industry. IIRC one of the trade mags
Process Today or some such title used to give a free chemical/corrosion
resistance chart away with their new year issue each year. A copy of such a
chart might be a useful addition to the FAQ if someone can get hold of a
current one.