: I have been told I could use black threaded pipe to install my propane appliances and also told this pipes interior flakes off when used with propane and to use only copper lines for my propane hook-ups. Which of these statements are correct and is one actually the one to use. Thanks.I have seen copper tubing flake off when the tubing is used behind restaurant equipment, because of the extra heat there or in hotter than normal places, like ovens. This is why ,I believe, aluminum tubing is used to feed propane from controls to ovens and pilots. The aluminum tubing wont flake with heat.I have never seen black pipe flake. Lou is right, both are used in Canada and check your local codes. In PEI, Canada, ranges must be hooked up with flex tubing from the copper tube behind the unit. This is done so consumers wont break the copper tube when they move the range to clean behind. http://www.isn.net/~propane Noel