Pilgrim wrote:
What do I need to know and what precautions do i need to take to sweat
solder a 1/4 turn ball valve in 3/4" Cu pipe? The ball turns in a
plastic seat that looks like teflon.

In addition to what everyone else said, please make sure
that you are soldering *dry* pipe. Open a valve at the
low end of the system and drain completely in the HAZ.
Roll up a paper towel and soak up the excess.

Crocus cloth and flux are your friends. Use both to excess.

When re-soldering an end cap on to wet pipe,
do not look at the end of the pipe with your remaining eye.

--Winston

--

Don't *faff*, dear.