Transition from 3/4" rigid copper to 3/4 soft copper

TVC15

I have to bring a 3/4" copper line through an attic space and down a exterior wall - replacing galvanized. It's impossible to solder the copper within the attic space at the transition to the exterior wall. I'm going to attempt to use soft copper to go across the attic space and down the wall to avoid soldering. At the exterior wall I have to transition from the 3/4" soft copper to 3/4" rigid copper. I was told the outside diameter of rigid is not the same as soft. Is this correct information? If so, how do I connect both pieces of copper pipe?

biggles

3/4 copper either or is the same diameter measured from the ID or the OD couple it up and both ends should slide in tight to solder up soft will heat up quicker then the hard drawn..just keep the flame on the coupling 1"-2" range with flux your good to go

joecaption

Sure hope you live in an area where it never freezes, if it does with copper pipe your going to have an instant sprinkler system in your house.