On Tue, 24 Mar 2009 20:12:34 -0700 (PDT),
wrote:

On Mar 24, 2:01Â*pm, wrote:
On Mar 24, 2:02Â*am, Bob Hoover wrote:

I'm leaning toward that myself. When the tubes came out of the acid, I
rinsed them in clean tap water and then let them air-dry. I actually
watched them rust in a period of 5 minutes.

Harry

Another thought - I've seen some EMT that has been painted/coated on
the inside. The acid won't remove that. If that is the kind of EMT
you are using for practice burn out the paint and then use a wire
brush from the plumbing section to clean it out.
=======================
Leon McAtee
The metalurgy of EMT is a crapshoot. It could have all kinds of
"alloys" in it, and poorly distributed - particularly if Chinese.

When building anything with EMT I acid dip and braze. Attemting to MIG
it is futile, in my opinion.