On Wed, 06 Mar 2013 10:42:29 -0500, Ned Simmons
wrote:

On Tue, 05 Mar 2013 18:09:40 -0500, wrote:

On Tue, 05 Mar 2013 17:06:59 -0500, Ned Simmons
wrote:

On Tue, 05 Mar 2013 13:22:02 -0500, wrote:

On Tue, 5 Mar 2013 11:18:31 -0500, "Jim Wilkins"
wrote:

"Joe Gwinn" wrote in message
. ..
In article
,
Pilgrim
wrote:

Can any one tell me what the difference between rigid conduit and
iron
pipe? inner finish threads on the pipe and in the fittings and any
other
significant differences.

It's not a good idea to use iron water pipe for rigid conduit, even
though the sizes are similar, because water pipe usually has a rough
and sharp longitudinal welded seam that will cut through the wire
insulation during pulling. Conduit, being intended for wire, has a
smooth-walled bore.

Joe Gwinn

Is either better for structural uses?
jsw

Yes and no -depends. Black Iron water/gas pipe today is pretty much
an unknown, quality-wise. Cheap rough Chinese crap in many cases - in
which case Rigid conduit MAY be stronger/more predictable.

ASTM A53 is the standard that covers common steel plumbing pipe in the
US. Even Home Depot and Lowes cite that spec for the black pipe they
sell, so I don't think it's fair to say that the quality of black pipe
is an unknown. It may not be exactly what one might want for a
particular purpose, but it is qualified for its intended use.

The steel dealers around here stock uncoated A53 pipe, which is much
better looking than the black stuff, and preferable if you're welding
or painting it.
Just because it SAYS it meets ASTM A53 spec doesn't necessarily mean
it DOES, you know. A lot of "counterfiet" material around these days.
And the crap will really hit the fan when they prove it was
substandard pipe that caused a gas explosion that levelled a city
block.

An imaginary future disaster is not evidence that there's currently a
problem.


One reason given why a pipefitter would not do my external gas barBQ
line in black pipe was he "won't work with that ****" anymore.

Nor is an opinionated plumber. (There's one for the Department of
Redundancy Department.)
Well, in building airplanes we have found a LOT of so-called 4130 is
nothing close to spec, and also a lot of 6061T6 aluminum. It's all
stamped with the proper identification, but the 6061t6 will crack if
bent to even twice the allowable radius, and doesn't weld worth crap,
and the 4130 is WAY below spec for tensile and yield.

Don't want to fly with that - so we don't accept chinese material
without independent confirmation of quality - and then only if
American, Canadian, or European product is not available.