Water
You need to give more info than simply "rigid pipe". What kind of "rigid pipe", what pressure will it have and where you are burying it.
No, it is not.
Mostly used for plumbing inside a house. -Personally, I prefer PEX, easier to install and lasts longer.
If the copper is big enough, you can treat it as if it were cast and use packing and sealant. If the diameters are too different, you can use a rubber coupling to connect the two.
The threads
Masts need to be RIGID.
A 770 Greenlee hydraulic pipe bender bend is used for rigid steel conduit from 2" to 4".
I am sorry, but can you PLEASE rephrase your question? Can WHAT be used for copper pipe? When? How? Why?
Grooved method? Threads on the end of the pipe? There is no tube or pipe in copper with threads. You can end a copper pipe with a connection that is threaded to accept steel pipe.
It is very easy to damage any copper pipe.
YOU thread or braze copper pipe Copper tubling you solder, braze, flaire, compression ring, mechincal joints
no