Sweating shower valve with small leak

Whats the best way to sweat a new shower valve where the water leaks. How do you get the solder (sorry spelling) to get hot enough? Do the pros really stick some bread in the pipes?

Thanks,
s steve

You cannot solder if there is any water in the joint. Even a drop of water at the right moment can spoil a joint. Bread crumbs are an old trick. Can lead to clogged cartridges. There are some newer Gel type balls which do the same thing, and then are dissolved. You can try to use a shop vac to suck or blow enough water out of the line. There are some tools to solder on a valve...it goes thru the open valve and then expands in the upstream pipe. Then there are freeze kits available to do a local freeze on the pipe.

solder

The proper way since the joint could be contaminated inside, would be to take it apart and redo the joint. If you cannot get the water out of the joint you will never be able to heat it hot enough, at least until you boil all the water out, therefore you may have to cut the pipe and allow the water to escape that way.