Welding "Black Iron" Pipe

I want to build a custom lumber rack for my pick-up truck, and the most easily available material for the job that I can think of is the so-called "black iron" pipe used for plumbing natural gas lines, etc. (I'd be using ~2" diameter pipe). I don't know what "black iron" is, but I suspect that it is not iron at all. Probably some sort steel. Is this stuff weldable (I'll be using MIG with C-25 gas)?
Thanks

http://www.finishing.com/312/03.shtml says,
It is hard to answer questions out of context, but because you are with a water utility, I'll assume you are referring to black iron pipe. In this context, 'black iron' is just slang referring to steel pipe with black paint on it as opposed to being galvanized. As the son of a plumber, black iron was used on gas pipes, and still is, whereas glavanized piping was used (in those days) on waste piping.
=====Artemia Salina wrote:
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Al Patrick wrote:
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When we bought our first house we were told that the use of galvenized pipe in the waste line was not to code, because of rust-through. The approved materials were waste-rated PVC or "cast iron". That was in Oregon in the mid 90's. I don't know if "cast iron" meant really real cast iron or just really cheap, extra thick non-galvenized pipe (we got PVC).
------------------------------------------- Tim Wescott Wescott Design Services http://www.wescottdesign.com

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Real cast iron. Still required in some areas under slabs and for the main waste pipe where it exits the foundation. For commercial/institutional construction drainage, waste and vent is usually cast iron or thinner DWV grade copper.
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ATP* wrote:
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Come to think of it that PVC pipe was coupled to the existing really real cast iron pipe that went through the foundation out to the street.
Forgot about that.

Black iron pipe is a slang term given for standard steel pipe, often without pressure ratings. You are not going to find cast rion pipe two inches in diameter and twenty feet long so rest assured you have a mild steel pipe. You should have no difficulty welding the material. It sometimes has a black varnish like finish that will burn off when you weld. Randy
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