"john" wrote in :

Is it common to solder copper pipes under a kitchen sink, or is it
almost universal to use compression connections there? If you found
some already soldered there, and wanted to put new connections in,
would you use a torch
to remove the old ones, then use compression connections for the new
ones? Or what?

Don't know about common, but I hate compression fittings.
Everytime I have to turn a valve attached to a compression fitting, I
worry I would disturb the fitting and cause a leak.

I did put in solder fittings under a sink. Just had to make sure there
are no plastic pipes nearby and put metal shield on anything that
burns easily (wall or cabinet).

Especially if pipes come out of a concrete slab foundation, and only
stick up 2 or 3 inches, so there is not much excess pipe length to
cut and start over.



I do sweat & compression depending on the situation. Never had one "get
disturbed". I just check the box for each particular comp fitting for how
much to tighten after contact. 1/2 turn is what I usually see if I recall
and that's all I do. Not 1/2 plus a little more. With various comp type
fittings, go by the book. If it drips a tad, then go another 1/6 turn.
You can always tighten a tad but leaking because it's overtight means
take off and redo. Good part about compression is no heat to be concerned
about surroundings or mess up internals of valve.