On Tue, 11 Oct 2011 06:09:12 -0700, Larry Jaques
wrote:


Why black pipe? We're not doing nat. gas here. I used all 3/4"
galv steel for my main and 3/4 x 3/4 x 1/2 tee's UP, then two 90 deg
street el's and 1/2" down to my outlet, ball valve and Q/C.

Galv flakes a lot. I hope you use a FLR on each drop, with or without
lube. F'rinstance http://goo.gl/2yi3z .

Indeed. Ive made a point to NEVER use Galvanized pipe in any of the 100
or so air systems Ive designed and installed. This after repeatedly
having to unchoke or replace air solenoids that were
filled/blocked/ruined by flakes..sometimes BIG flakes of Galv.

Black pipe is cheaper, and while it may rust a bit more internally..it
reaches a point where little comes out of it..and when it does..is dust
that passes through such devices nicely. Particularly when one does
moisture control before the air reaches the plumbing.

Copper is best..but as Larry indicated...figure out which kid you like
the least, then sell him/her for the bucks to install it.

When a joint of 3/4 black, 20 feet long is $11 or less...its the most
viable candidate for most folks.

Gunner

"In the history of mankind, there have always been men and women who's goal
in life is to take down nations. We have just elected such a man to run our
country." - David Lloyyd (2008)