I have a all brass shower valve that has four threaded ports.

I have used a brass male adaptor with one threaded end and one socket end.
I used pipe dope and teflon tape to thread into each port, then I plan to
solder the other end to copper pipes.

The male adaptor is only about 2" long. If I solder one end to a copper
pipe, I will have to heat up that fitting, and the adaptor being so short,
the high heat will be transfer to the other end and I wonder if it will mess
up the pipe dope and teflon tape...and may cause it to leak?

Is this concern valid?

Thanks,

MC