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good choice for first-time plumbing repair?
wrote:
I've got a leaky hot-water pipe joint that feeds the dishwasher.
Leaks from the tee where the shut-off valve is, under the sink. Is
this a good choice for my first-ever DIY plumbing attempt? I'm plenty
handy with wood and electrical, but haven't attempted plumbing. I've
got the flux/solder/etc, and have watched a zillion shows and read a
zillion books, Whaddayathink? Can I just resolder the thing, or
does it have to come apart and go back together again?
To give your question a direct answer. If it's leaking from a soldered
joint between copper piping and a fitting, don't try and fix it by just
reheating the joint or piling solder on the outside.
Far and away the principle reason soldered plumbing joints leak is that
the installer either didn't properly clean and flux both the pipe and the
inside of the fitting before heating them and applying solder, or he/she
didn't heat the joint area enough so that it reached soldering
temperatures all the way away around the fitting. You can't clean the
mating surfaces while the pipe and fitting are still together, and no
amount of heating will make solder wet onto dirty surfaces.
If you're going to fix the leak by resoldering, you will have to
disassemble things to accomplish the job.
Soldering copper plumbing is almost a no-brainer, providing you do three
things correctly:
1. The srfaces which will be wet with solder have to be clean and bright.
This is can be accomplished with abrasive cloth or wire brushing, but it
must be complete with no traces of "brown" (oxidized copper) left.
2. Flux has to be applied to all the surfaces to be joined.
3. Enough heat has to be applied with a torch all around the fitting so
that wire solder will melt immediately when touched to the juncture at
the end of the fitting and the pipe, immediately after the torch flame is
moved away. When done properly, the solder will melt, get sucked into the
joint and "run" all around the fitting without further effort. (Don't
bump or move the pipe until you've waited long enough for the solder to
chill.)
In tight quarters you can shield walls or other things you don't want
scorched with two or three folded layers of kitchen aluminum foil. It'll
reflect the heat away fine, as long as you don't play the torch directly
onto it.
That being said, there's nothing wrong with using compression fittings
for a repair job like the one you're describing. You might want to aquire
a pipe cutter if you don't already have one. They make nice little
cutters for close quarter work which will swing around a pipe that's only
an inch or so away from a wall. It's much easier to use one of those than
trying to bull your way through copper with a hacksaw while cramped under
a sink.
Good luck,
Jeff
--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)
"If you can keep smiling when things go wrong, you've thought of someone
to place the blame on."
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