On 2/22/2017 5:06 PM, John Rumm wrote:
On 22/02/2017 13:19, DerbyBorn wrote:

That is a mess. Those places where I see PTFE poking out, look to me as
if they were intended to have a fibre washer fitted between flat faces.
You might get PTFE to seal, but only if you can get a regular layer of
PTFE around the threads and of just the right thickness, which is
unlikely - so it will leak.


What I was thinking (Looks like a tap elbow)- I would be inclined to take
the photo to a decent Plumbers Merchant and get the correct fittings for
the job.

Althought PTFE on the tread is not the solution, it should be wound on so
that screwing the fitting will tend to tighten the tape - and not push it
out.

If one were going to try and get a seal on that with PTFE you would need
to be quite careful with the winding of it - basically creating a taper
shape[1] on the thread with the tape, so that the "screw in" resistance
increases sharply as the stub penetrates further into the female thread.

e.g. you start with say 4 or 5 turns toward the tip of the thread and
work up to many more (10 to 20) laid up toward the back of the thread) -
winding the tape on "edgeways" so that it folds up helps build thickness
faster.

Agreed.

Another technique with it is to roll the tape between your fingers to
make "string" and then wind that helically into the threads. You can
also, with care, fabricate a replacement for the fibre washer on a tap
connector by winding several turns of this PTFE "string" on to the step
which should take the washer. Emphatically *not* recommended as a
permanent fix, but in the absence of proper washers I have done it a
couple of times for friends on a Sunday evening, when miles away from my
toolboxes. Most of these include a tobacco tin containing some of these
washers, fuses, fuse wire, and a couple of chocolate blocks. And bits of
red and green/yellow sleeve.