Problems with threaded valve connections

Hi guys, I'm having some problems with the threaded valve connections on a bathtub install. It has a total of 5 threaded connections....all are female copper to brass connections except one. The male threaded copper connection to brass is causing me the most problems. 1. Can this connection be soldered? 2. Can any threaded connection be soldered???? 3.Should I purchase a brass threaded connection and try it with joint compound? I don't have enough room for a union. I'm pulling my hair out here.....please help!!

tub faucet

Cut the copper and dope the male c x male iron pipe adaptors.
Put it back together with copper repair couplings.

This should not be a difficult connection. They are used all the time.
The proper procedure is to use some pipe dope on the threads, assemble hand tight, then about 2 turns wrench tight. You will develop a 'feel' for how tight. Undertigtening, or overtightening, can both be bad.

Many pros use both 2 to 3 wraps of teflon tape PLUS some pipe dope. Shouldn't be necessary, but can't hurt and seems to be foolproof for a lot of guys, so try it.

I'll give it a try. I've never used pipe dope only joint compound and teflon tape so I'm off to the hardware store.....I'll keep you posted

Thanks guys. I think my main problem was overtightening the connections. It really doesn't take much tightness to keep them from leaking.