On Tuesday, 21 February 2017 20:33:07 UTC, Chris Green wrote:
newshound wrote:
On 2/21/2017 7:36 PM, Chris Green wrote:
tabbypurr wrote:
3 plumbing joints done with ptfe tape all leak. I mostly don't use ptfe
to seal joints. 2 of the joints are 15mm compression tee (with one male
end, one female end) onto an extension piece, the other is extension piece
onto brass threaded ballcock. 1.5 turns of yellow/gas ptfe tape each, all
neatly in place. I admit to not being clear how the nut would seal to the
tee it's on. The one joint done with fibre washer & gloop works fine of
course, but I don't think that approach can be used with the other joints.


I'm clearly making a basic mistake here. Did I mention I don't like plumbing?

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix - where did you put the
tape anyway?

Although this is the conventional wisdom, IMHO it is always worth
putting PTFE tape on the threads because it reduces the friction
coefficient. So you get more axial force for a given torque. It's the
axial force which makes the seal.

It's the squishing of the olive round the pipe that makes the seal
surely. OK, some PTFE tape on the thread may help by lubricating it
but surely a quick dab of grease or oil would actually work better as
a lubricant.

The problem joints don't involve a pipe or olive. They're where 2 parts are screwed together.


NT