Black iron. But you'll need to rent a threader and cutter.

s


"Jeff Dieterle" wrote in message
...
I will be installing quite a bit of copper tubing. Probably a 60' run of
3/8" hi-pressure run and several normal pressure 1/2" runs in the
neighborhood of 50-75 feet and possibly a 3/4" run of 25 feet or so (large
tankless water heater).
Wondering if there is a lower cost do-it-yourself alternative to copper
tubing. I installed underground plastic tube supplied by LPG dealer and
they came out to install the fittings and terminate it to the tank and
regulator. They way I get it the plastic fitting is a proprietary system
that requires some special connectors, tools and training. Even if this
stuff was adequate for indoors use, by the time I paid for the tube,
fittings and the service man to install all the connectors I'm back at the
price of copper.