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#42
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PTFEed Joints weeping
I don't see how it can work then. You have completely different materials
and no olive, so really you have no chance of it working long term I feel. I hate plumbing as well, but sometimes needs must as they say, but these days, I think I'll leave it to the profs as I don't like trying to find my loft mounted tap with no sight and a loft full of lagging. Brian -- ----- - This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please! wrote in message ... On Tuesday, 21 February 2017 19:21:39 UTC, Harry Bloomfield wrote: tabbypurr brought next idea : 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. Compression joints should not need anything else to seal them, the olive is supposed to deform to make the seal between fitting and nut and the pipe. The pipe end should go well into the fitting, to keep things aligned. the joints in question don't have an olive. They're screw threaded extensions to compression fittings. The tape goes on the screw thread. And yes, I do use gloop on compressions, old pipe does not seal reliably without. NT |
#43
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PTFEed Joints weeping
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. |
#44
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PTFEed Joints weeping
On Wednesday, 22 February 2017 16:59:33 UTC, newshound wrote:
On 2/21/2017 11:27 PM, tabbypurr wrote: On Tuesday, 21 February 2017 20:35:56 UTC, newshound wrote: On 2/21/2017 8:15 PM, tabbypurr wrote: On Tuesday, 21 February 2017 20:05:29 UTC, newshound wrote: On 2/21/2017 7:56 PM, tabbypurr wrote: On Tuesday, 21 February 2017 19:32:23 UTC, newshound wrote: On 2/21/2017 7:03 PM, 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? NT When you say compression tee, do you mean the pipe has an olive on it? Like an ordinary compression fitting (that takes pipe with olive) except that one end is reversed, ie male not female. It thus has a nut on that screws onto another fitting. I've added 2 threaded extension pieces, one on each port, to make the combined fitting long enough to reach both pipe and ballcock. So where is the seal? I thought the ptfe between the screw threads was going to do it, but clearly not. Assuming these are parallel threads, you will need a soft washer on the axial face (unless you fill up the thread clearance with some sort of fluid sealant)0 yes, hoping I have a suitable washer now. IIRC fittings to a ballcock are also normally done with an olive. Neither the current or previous one were/are. The male bit of the compression elbow is screwed onto the ballcock. OK then you need another soft washer (fibre or rubber) on the axial face. right You should not be trying to use PTFE tape to seal any significant water pressure. But IMHO it is worth using tape on compression fittings *to reduce the friction*, which means you get more axial pressure for a given torque. Lots of people tell you that you must not put tape *over* the olive or the cones but a single turn won't matter. There are basically three ways to seal with threaded connectors. One is using tapered threads, these are sealed with fibre, traditionally hemp but now usually Loctite synthetic thread. A smear of "Boss White" is also needed. The second is the washing machine or garden tap connector. You need a soft washer, either rubber or fibre, trapped in the female (hose) fitting against the end face of the tap. Tap fittings use a variant of this, with a thinner fibre washer trapped against the tap by a flange on the male fitting. The third is the compression fitting, where you are trapping an olive between cones on the male and female parts. This relies on squeezing the olive tightly enough on the pipe so that fluid cannot flow between the olive and the pipe (sometimes a problem with chromed pipes). There are liquid sealants which can be applied to threaded joints, I usually think they are a bit of a "bodge" but sometimes you are constrained by, for example, a damaged cone on a fixed part, or a scored pipe. I always carry some in my plumbing toolbox. I'll see if I can get washers in there, but from a quick look I doubt I can. In which case I could use some sort of fairly quick setting stuff, but that still won't seal the nut to the male end of the compression fitting. elbow is like this: https://www.raygrahams.com/images/th...052314_700.jpg That needs a tapered male thread although you might get away with a washer I'm more than puzzled by the idea of using a tapered thread with it Tapered threads are sized so that they become completely tight before the male thread has bottomed in the female component. On its own, a tapered thread can't normally make a gas-tight seal, but the leakage path will be small, so it can be sealed by something like boss white. A down-side of tapered joints is that you don't have much control of the orientation of the parts at the point where they become tight. However by having something like hemp threads wrapped around the male threads, you can influence the point at which it becomes tight, and hence control the angular orientation. Tapered threads are not so commonly used in copper systems, but they were the standard system in "old" iron pipe, e.g. in "gravity" hot water systems, and are sometimes used for hand-rails and guard rails. It's a bit of an art building a complicated "3D" system in iron. extensions look like this but without the nut on: https://www.raygrahams.com/images/th...038720_188.jpg I would expect there to be an olive between the nut and the fitting which nut and which fitting? I can't imagine how one would get an olive between the extension piece and the elbow. This picture shows two components. A sort of sleeve with a female thread at one end, and a male thread on the other. that's what the extension pieces are There is a nut on the male thread. I would expect there to be an olive "inside" the nut. This would let you seal a piece of copper pipe to the right hand end of the fitting, by tightening the nut (with the olive in place). But that lot doesn't come into it. No nut, no olive, no pipe. NT The bottom line is, this explains why you are getting leaks with PTFE tape only. You either need a rubber or fibre washer to give an axial seal, or taper threads with sealant, or perhaps some sort of bodge with a setting sealant. |
#45
Posted to uk.d-i-y
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PTFEed Joints weeping
Anyone using PTFE tape on car wheel nuts?
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#46
Posted to uk.d-i-y
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PTFEed Joints weeping
On 22/02/2017 19:01, newshound wrote:
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. Yup, I found that I can quite reliably get a seal on parallel male and female threads using the tape trick. Last time was when I wanted to test the soundness of the rads after multiple mods and changes. I needed to bodge a way of connecting my pressure gauge to a rad top connection. The gauge made a good seal on to the end of a service valve with its internal washer, then all I needed to do was get a service valve to seal on the top boss of the rad (having removed the bleed valve). Application of PTFE as previously described worked nicely. I was then able to pressurise the system, and leave it for 48 hours to check that there was no drop off in pressure. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#47
Posted to uk.d-i-y
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PTFEed Joints weeping
On 22/02/2017 19:30, wrote:
On Wednesday, 22 February 2017 16:59:33 UTC, newshound wrote: On 2/21/2017 11:27 PM, tabbypurr wrote: On Tuesday, 21 February 2017 20:35:56 UTC, newshound wrote: On 2/21/2017 8:15 PM, tabbypurr wrote: On Tuesday, 21 February 2017 20:05:29 UTC, newshound wrote: On 2/21/2017 7:56 PM, tabbypurr wrote: On Tuesday, 21 February 2017 19:32:23 UTC, newshound wrote: On 2/21/2017 7:03 PM, 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? NT When you say compression tee, do you mean the pipe has an olive on it? Like an ordinary compression fitting (that takes pipe with olive) except that one end is reversed, ie male not female. It thus has a nut on that screws onto another fitting. I've added 2 threaded extension pieces, one on each port, to make the combined fitting long enough to reach both pipe and ballcock. So where is the seal? I thought the ptfe between the screw threads was going to do it, but clearly not. Assuming these are parallel threads, you will need a soft washer on the axial face (unless you fill up the thread clearance with some sort of fluid sealant)0 yes, hoping I have a suitable washer now. IIRC fittings to a ballcock are also normally done with an olive. Neither the current or previous one were/are. The male bit of the compression elbow is screwed onto the ballcock. OK then you need another soft washer (fibre or rubber) on the axial face. right You should not be trying to use PTFE tape to seal any significant water pressure. But IMHO it is worth using tape on compression fittings *to reduce the friction*, which means you get more axial pressure for a given torque. Lots of people tell you that you must not put tape *over* the olive or the cones but a single turn won't matter. There are basically three ways to seal with threaded connectors. One is using tapered threads, these are sealed with fibre, traditionally hemp but now usually Loctite synthetic thread. A smear of "Boss White" is also needed. The second is the washing machine or garden tap connector. You need a soft washer, either rubber or fibre, trapped in the female (hose) fitting against the end face of the tap. Tap fittings use a variant of this, with a thinner fibre washer trapped against the tap by a flange on the male fitting. The third is the compression fitting, where you are trapping an olive between cones on the male and female parts. This relies on squeezing the olive tightly enough on the pipe so that fluid cannot flow between the olive and the pipe (sometimes a problem with chromed pipes). There are liquid sealants which can be applied to threaded joints, I usually think they are a bit of a "bodge" but sometimes you are constrained by, for example, a damaged cone on a fixed part, or a scored pipe. I always carry some in my plumbing toolbox. I'll see if I can get washers in there, but from a quick look I doubt I can. In which case I could use some sort of fairly quick setting stuff, but that still won't seal the nut to the male end of the compression fitting. elbow is like this: https://www.raygrahams.com/images/th...052314_700.jpg That needs a tapered male thread although you might get away with a washer I'm more than puzzled by the idea of using a tapered thread with it Tapered threads are sized so that they become completely tight before the male thread has bottomed in the female component. On its own, a tapered thread can't normally make a gas-tight seal, but the leakage path will be small, so it can be sealed by something like boss white. A down-side of tapered joints is that you don't have much control of the orientation of the parts at the point where they become tight. However by having something like hemp threads wrapped around the male threads, you can influence the point at which it becomes tight, and hence control the angular orientation. Tapered threads are not so commonly used in copper systems, but they were the standard system in "old" iron pipe, e.g. in "gravity" hot water systems, and are sometimes used for hand-rails and guard rails. It's a bit of an art building a complicated "3D" system in iron. extensions look like this but without the nut on: https://www.raygrahams.com/images/th...038720_188.jpg I would expect there to be an olive between the nut and the fitting which nut and which fitting? I can't imagine how one would get an olive between the extension piece and the elbow. This picture shows two components. A sort of sleeve with a female thread at one end, and a male thread on the other. that's what the extension pieces are There is a nut on the male thread. I would expect there to be an olive "inside" the nut. This would let you seal a piece of copper pipe to the right hand end of the fitting, by tightening the nut (with the olive in place). But that lot doesn't come into it. No nut, no olive, no pipe. NT The bottom line is, this explains why you are getting leaks with PTFE tape only. You either need a rubber or fibre washer to give an axial seal, or taper threads with sealant, or perhaps some sort of bodge with a setting sealant. Done & leakproof http://i68.tinypic.com/xc9pjn.jpg Nice job, that ought to do it ;-) -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#48
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PTFEed Joints weeping
In article ,
charles wrote: It probably doesn't help, but I'd have done all of that using end feed solder fittings. Which if you take care, never leak. Very difficult to get a good joint on a pipe that still has water around. Not difficult to drain those from a tank? I wouldn't wave a blowlamp near a plastic water tank, either, You protect it from heat - same as anything else close to where you're soldering, if needed. -- *If a pig loses its voice, is it disgruntled? Dave Plowman London SW To e-mail, change noise into sound. |
#49
Posted to uk.d-i-y
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PTFEed Joints weeping
In article 2,
DerbyBorn wrote: Anyone using PTFE tape on car wheel nuts? Why would you? A smear of copper grease will stop them seizing. -- *Parenthetical remarks (however relevant) are (usually) unnecessary * Dave Plowman London SW To e-mail, change noise into sound. |
#50
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PTFEed Joints weeping
On Tuesday, 21 February 2017 23:29:30 UTC, tabby wrote:
Of all the plumbing spanners my flat stamped one is one of the more useful. It's more than thick enough to get serious torque on the nuts - but it is the thickest stamped one I've ever seen. The slight offset makes it even more getinnable. It's designed for car fans. Laser brand. NT |
#51
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PTFEed Joints weeping
On 22/02/2017 16:59, John Rumm wrote:
On 22/02/2017 16:05, DerbyBorn wrote: wrote in news:6e07a80c-d49f-477e-ba82- : On Tuesday, February 21, 2017 at 7:48:05 PM UTC, Chris Green wrote: Well basic mistake one to my mind is using PTFE tape with compression joints. PTFE and compression joints don't mix - The apprentice uses it without thinking. The journeyman avoids it without thinking. The master uses it thoughtfully. I've never had a problem with it. It is slapping it onto the treads thinking it will improve the seal that is so wrong. Is anyone suggesting that? I find many do, or use as the reason why they are using PTFE tape, often fully covering the olive as well. |
#52
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PTFEed Joints weeping
I find many do, or use as the reason why they are using PTFE tape, often fully covering the olive as well. +1. In my house it has one application - on radiator tails and top bungs. |
#53
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PTFEed Joints weeping
On Thursday, 23 February 2017 21:05:14 UTC, DerbyBorn wrote:
I find many do, or use as the reason why they are using PTFE tape, often fully covering the olive as well. +1. In my house it has one application - on radiator tails and top bungs. Maybe it's time for a wiki page on ptfe. NT |
#54
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PTFEed Joints weeping
On 23/02/2017 20:26, Fredxxx wrote:
On 22/02/2017 16:59, John Rumm wrote: On 22/02/2017 16:05, DerbyBorn wrote: wrote in news:6e07a80c-d49f-477e-ba82- : On Tuesday, February 21, 2017 at 7:48:05 PM UTC, Chris Green wrote: Well basic mistake one to my mind is using PTFE tape with compression joints. PTFE and compression joints don't mix - The apprentice uses it without thinking. The journeyman avoids it without thinking. The master uses it thoughtfully. I've never had a problem with it. It is slapping it onto the treads thinking it will improve the seal that is so wrong. Is anyone suggesting that? I find many do, or use as the reason why they are using PTFE tape, often fully covering the olive as well. Covering the olive will alter the sealing properties, and can be used to fix some categories of leak. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#55
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PTFEed Joints weeping
In article ,
John Rumm wrote: I find many do, or use as the reason why they are using PTFE tape, often fully covering the olive as well. Covering the olive will alter the sealing properties, and can be used to fix some categories of leak. I do use PTFE on the olive after cleaning the pipes thoroughly, and making sure there are no inline scratches. Examine more carefully than I would for a solder fitting. And oddly, never have a compression fitting leak. ;-) -- *Women who seek to be equal to men lack ambition. Dave Plowman London SW To e-mail, change noise into sound. |
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