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

(...)

Around 8 or so years ago we discussed the subject here, after I'd
complained about the fume fever, and someone -- maybe you --
recommended that treatment.

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.

Someone in the discussion had recommended against the baking soda
because he said it could form a salt that would stay in the pores of
the steel. So, just for a test, I simply rinsed the EMT off, scrubbing
good with a fiber brush, dried them, and stuck them on a shelf in my
dampish basement to see what happened. Until I had a really serious
flood last fall, there wasn't a speck of rust on them. They were still
shiny steel. Now one side of the pieces have a slight blush of rust.

I'd forgotten that. I'll drop the 'baking soda solution
step' and use an aggressive scrub with clear water next time.

Unfortunately, I haven't welded EMT since that day. d8-(. I had just
been using it for practice, anyway.


The vapor created by the soak is hot, plentiful
and Very Nasty smelling, so I only do this outside
whilst standing upwind.

Yeah, I did it outside. I will not open a container of hydrochloric
acid in the same room with my machine tools -- or anything else I
don't want to rust.

Yes. That is hugely important.

I stored my jug of HCl solution in a garden shed away from
machine tools.

The resulting steel welds really well. I've avoided
zinc fever so far.

The fumes created by gas cutting powder - coated steel
left my nose offline for most of a year, though.

(Don't do that.)

I'll try to remember that.


--Winston