Normally you unscrew the valve assembly (and pull it out) BEFORE you
sweat the valve on - then replace when it cools. The assembly unscrews
at the base of the screw.

best
mjb920 wrote:
I am having a problem sweating a quarter turn shut-off valve for a
bathroom sink. It seems that since the valve is such a large chunk of
brass it takes a lot of heat to get it hot enough to melt the solder.
The valve gets damaged from the heat and then leaks. Since this is a
ball valve there is nothing I can take apart before I heat it. Thanks
for any advice you can give me. Jim