On Tue, 31 Jan 2012 18:13:31 +0000, David Billington
wrote:

Jim Wilkins wrote:
"Winston" wrote in message
...

Ed Huntress wrote:

On Tue, 31 Jan 2012 06:07:14 -0800,
wrote:

So I cut off some one-foot test pieces of EMT and stood them up in a
plastic peanut butter jar, and poured muriatic acid around them to a
depth of xix inches or so. The galvanizing stripped off in minutes.


--Winston


The caustic soda (NaOH) in drain cleaner also removes zinc, without
affecting the steel. The CO2 in the air converts any lye you didn't remove
into washing (Na2CO3) or baking (NaHCO3) soda. All are mildly protective of
the steel, but not enough for outdoor use. You can see the difference
between the silvery zinc and greyish steel to tell when it's done.

Drain cleaner doesn't release any fumes to damage your lungs or machinery.
Spilled HCl can be more dangerous than other strong acids because it soaks
in rather than reacting immediately with the outer layer of dead skin.

jsw



A quick heads up would be to check the ingredients before buying the
drain cleaner as my neighbour bought some, I'm in the UK, and found that
the main ingredient was sulphuric acid. My neighbour took the drain
cleaner back where he bought it for a refund, as it was expensive, and
he already had quite a quantity of sulphuric acid that he had bought to
make pickling solution for his loco construction. Not all drain cleaners
in the UK are sulphuric acid based though, many are caustic soda which
is readily available for the purpose.

In the US, there appears to be only one brand of over-the-counter
drain cleaner that is straight, powder NaOH (lye). It's Roebic Crystal
Drain Opener, and the main (or sole?) retail outlet is Lowe's.

However, there are soap-making-supply companies that sell lye over the
Internet, and it's much cheaper. The trouble is that small quantities
tend to eat up any savings with shipping costs.

I buy from Essential Depot:

http://www.essentialdepot.com/

They've given me very good service, although I haven't bought any
larger quantities of lye for about a year.

--
Ed Huntress