On Sat, 22 Nov 2003 21:37:39 -0800, jim rozen wrote:

Interesting story, last night I went down the shop
to do some work and found a small puddle on the floor.
A solder joint where the copper hot water pipe was joined
to a 3/8 NPT adapter into an old bronze valve had let
loose and was leaking water onto the floor.


The interesting part though was that today I took the
parts into work to give them the close hairy eyeball
under a good microscope, and while looking at them,
I realized that whoever made up the threaded fitting
between the adapter and the valve, used some unusual
compound in the threads - in fact, he had used nothing
more than cotton sewing thread. It was all bunched
up at the root of the male copper threads, but there
were several layers of thread that I could unwind and
inspect.
It was Plumbers hemp not cotton unless he was a very unusual plumber.

There wasn't any dope or tape or matrix material of
any kind mixed in with the thread, all of the fibers
were clear and freely visible.
There should have been what is now called plumders jointing compound, back
the it was called all sorts of things depending on where you were.
I wonder if this was a common practice 'way back when,' using sewing
thread to seal pipe fittings?
Yes

It seems to have worked just fine, as the only leak in evidence was at
the copper-to-copper joint, all of the threads were leak-tight.

The bronze valve btw had a) no washer left in it, and b) the screw to
hold the washer was mostly gone as well.

Ah the joys of old houses!
=====

--
Neil
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