The shutoff valve on my water heater has an extremely slow leak. A couple years ago I disassembled it by removing the handle and changing out either the packing or the rubber washer, or maybe both (can't remember now), which did help, but sometime in the past few months it's started to leak slowly again.

Can I buy a new valve and just swap the circled area, or must I solder a complete sweat fitting. I've never soldered copper pipes before but I'm not afraid to give it a try.

[![enter image description here](https://i.stack.imgur.com/w1iUx.jpg)](https://i.stack.imgur.com/w1iUx.jpg)

[![enter image description here](https://i.stack.imgur.com/lPS0j.jpg)](https://i.stack.imgur.com/lPS0j.jpg)