In article
,
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.


If it's a sweat fitting valve and not obviously easily disassembled,
it's teflon and should not be bothered by soldering, if you do it
properly. Wrap a damp rag around the middle if you like, but mostly
apply heat to the fittings, not the middle, and don't overheat - teflon
is fine at molten solder temperatures. Solder with it open. Apply enough
solder, not a vast excess, particularly if it's mounted in a vertical
run of pipe.

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