Had to move the propane tanks so I could pour a concrete patio.  I need to move the line.  The original line is 1/2" steel, which I don't feel like ripping out right now, I want to get the line in, and move onto other projects.  I have 3/8" flexible copper tubing, and these brass compression fittings.  The flare is from the original exterior end.  I'm coming off of a steel T, which has one side plugged.  Can I just run the copper tubing through the wall and end with the compression fitting and the flare?  Will the compression fittings make a gas-tight seal.  I'm not overly concerned about codes.  What should I put on the threads?  Teflon tape, or dope?  Thanks.

 

Natural gas will eat copper lines, propane may do the same. Use poly pipe.

WTF are you talking about?

OP, no teflon tape or pipe dope on a machine thread, compression fitting or flared fitting, only on a pipe thread end.

copper + propane= bad juju. it'll work for a while, maybe a good while, then it won't. black pipe or poly only, unless you want to run stainless. no galvanized, either.

AFIK (in Florida at least) nothing but steel inside walls.

What is "Utility Grade Coil" ?

Seems to me that if outside, it should be Type "K".

You should check your local codes.

I've never seen propane eat copper pipe, I guess they're gonna have to go back and swap out all those pigtails and risers on those tanks we put in.

3/8 seem a little small if your going from 1/2, 1/2" copper with flare fittings is what we used on our risers.

What ever you do spray every fitting ,even the ones you didn't touch, with leak check(soapy water works but is not the "recommended" liquid), propane is not to be fucked with

Best solution, have your propane suppliers service crew come do it

It's type L coil, if that matters.  I just had it on hand already.