Depends on what you are doing. soldered is for copper water lines. Threaded can be for water, gas, or anything else.
A coupling is a threaded or soldered solid fitting, a union is a fitting that joins two pipes and can be taken apart with wrenches.
Outdoor spigots are always threaded and not soldered on.
no
Nope, it can be brazed, soldered, threaded
It is a round threaded disk shaped thing that screws into a tee or other "female" threaded fitting to " plug" it up.
Yes
Threaded On End
Should be a threaded flared fitting
You can't. There is no fitting to do this. Galvanized has to be threaded.
A threaded copper fitting on the copper side, male or female, and the galvanized is screwed into it.
Exactly what it says threads are crossed inside the female fitting
A coupling