light leakage through loose threads, teflon tape

[Bill Sloman]

On Sunday, May 26, 2019 at 8:26:30 AM UTC+10, jurb...@gmail.com wrote:
> Teflon tape is junk. It is an automatic leak. It is not code for gas lines or any of that shit though the assholes at the DIYs will try to tell you it is. Less diligent plumbers use it because it is less messy than pipe dope.

For plumbing, a single layer of Teflon tape is inadequate. Six layers has always worked fine for me. And it does make the joint easier to tighten. I was told that it can make it easy enough to let you over-tighten and put enough tension on the socket to break it apart.

The main question here is how much pressure you are dealing with. If it is high then you might want to consider Locktite instead. I know it is not the EXACT purpose of the shit but then do we care what they wanted done with it once they got their money ? Fukum.

If you are involved with the possibility of any big liability here I would do serious product testing before it goes out the door.

The problem with the pipe dope in your application is if the thing is glass or glass supported then unscrewing it may break it.

Just what I am saying. Not the expert on LASERs n shit at all but I have been involved with some weird kinda processes. The guy to ask would have been the olman. he might have used like an alloy of maybe mercury and tin, to have it solid at operating temperatures but with a little Burnsomatic or maybe even a pencil torch you could get it hot and take it back apart easily.. but it has to not only well below the melting temperature, it also has to not cause too much thermal expansion or it might break or deform.

I am assuming right now that you have a reason for that tape.

George was using it as an anti-backlash device - as a solid lubricant. Metal-on-metal micro-welds, and you have to torque up a screw thread in a nut quite a lot to break the microwelds, and the screw jumps too far after the microwelds break.

Teflon tape offers smoother adjustment.

> The way I see that is first of all that tape is white and quite translucent. Duct tape would be better as a light shield. however it has an aggressive adhesive so maybe not so good. Will masking tape take the heat ? (only if you are dealing with any really pressure of course).

Not the point, in this particular case.

--
Bill Sloman, Sydney

 

On Saturday, 25 May 2019 23:26:30 UTC+1, jurb...@gmail.com wrote:

Teflon tape is junk. It is an automatic leak. It is not code for gas lines or any of that shit though the assholes at the DIYs will try to tell you it is. Less diligent plumbers use it because it is less messy than pipe dope.


The main question here is how much pressure you are dealing with. If it is high then you might want to consider Locktite instead. I know it is not the EXACT purpose of the shit but then do we care what they wanted done with it once they got their money ? Fukum.

If you are involved with the possibility of any big liability here I would do serious product testing before it goes out the door.

The problem with the pipe dope in your application is if the thing is glass or glass supported then unscrewing it may break it.


Just what I am saying. Not the expert on LASERs n shit at all but I have been involved with some weird kinda processes. The guy to ask would have been the olman. he might have used like an alloy of maybe mercury and tin, to have it solid at operating temperatures but with a little Burnsomatic or maybe even a pencil torch you could get it hot and take it back apart easily.. but it has to not only well below the melting temperature, it also has to not cause too much thermal expansion or it might break or deform.

I am assuming right now that you have a reason for that tape. The way I see that is first of all that tape is white and quite translucent. Duct tape would be better as a light shield. however it has an aggressive adhesive so maybe not so good. Will masking tape take the heat ? (only if you are dealing with any really pressure of course)

Teflon tape seals just fine, but it won't take mains water pressure, and many nonplumbers have used it to try to do that. It is approved for gas plumbing, but only the yellow gas grade stuff, which is thicker and missing the pinholes of the thin white stuff.

Polypropylene film is a reasonable alternative for low pressure water plumbing, it has the required properties. It's quicker & easier to use than linseed putty & hemp.


NT

 

[Phil Hobbs]

On 5/26/19 2:02 PM, tabbypurr@gmail.com wrote:

On Saturday, 25 May 2019 23:26:30 UTC+1, jurb...@gmail.com wrote:

Teflon tape is junk. It is an automatic leak. It is not code for
gas lines or any of that shit though the assholes at the DIYs will
try to tell you it is. Less diligent plumbers use it because it is
less messy than pipe dope.


The main question here is how much pressure you are dealing with.
If it is high then you might want to consider Locktite instead. I
know it is not the EXACT purpose of the shit but then do we care
what they wanted done with it once they got their money ? Fukum.

If you are involved with the possibility of any big liability here
I would do serious product testing before it goes out the door.

The problem with the pipe dope in your application is if the thing
is glass or glass supported then unscrewing it may break it.


Just what I am saying. Not the expert on LASERs n shit at all but I
have been involved with some weird kinda processes. The guy to ask
would have been the olman. he might have used like an alloy of
maybe mercury and tin, to have it solid at operating temperatures
but with a little Burnsomatic or maybe even a pencil torch you
could get it hot and take it back apart easily.. but it has to not
only well below the melting temperature, it also has to not cause
too much thermal expansion or it might break or deform.

I am assuming right now that you have a reason for that tape. The
way I see that is first of all that tape is white and quite
translucent. Duct tape would be better as a light shield. however
it has an aggressive adhesive so maybe not so good. Will masking
tape take the heat ? (only if you are dealing with any really
pressure of course)


Teflon tape seals just fine, but it won't take mains water pressure,

Of course it will. I've never had a Teflon tape joint leak. Where do
you live, the turbine hall of a hydroelectric dam?

Cheers

Phil Hobbs

 

On Sunday, 26 May 2019 23:53:04 UTC+1, Phil Hobbs wrote:

On 5/26/19 2:02 PM, tabbypurr wrote:
On Saturday, 25 May 2019 23:26:30 UTC+1, jurb...@gmail.com wrote:

Teflon tape is junk. It is an automatic leak. It is not code for
gas lines or any of that shit though the assholes at the DIYs will
try to tell you it is. Less diligent plumbers use it because it is
less messy than pipe dope.


The main question here is how much pressure you are dealing with.
If it is high then you might want to consider Locktite instead. I
know it is not the EXACT purpose of the shit but then do we care
what they wanted done with it once they got their money ? Fukum.

If you are involved with the possibility of any big liability here
I would do serious product testing before it goes out the door.

The problem with the pipe dope in your application is if the thing
is glass or glass supported then unscrewing it may break it.


Just what I am saying. Not the expert on LASERs n shit at all but I
have been involved with some weird kinda processes. The guy to ask
would have been the olman. he might have used like an alloy of
maybe mercury and tin, to have it solid at operating temperatures
but with a little Burnsomatic or maybe even a pencil torch you
could get it hot and take it back apart easily.. but it has to not
only well below the melting temperature, it also has to not cause
too much thermal expansion or it might break or deform.

I am assuming right now that you have a reason for that tape. The
way I see that is first of all that tape is white and quite
translucent. Duct tape would be better as a light shield. however
it has an aggressive adhesive so maybe not so good. Will masking
tape take the heat ? (only if you are dealing with any really
pressure of course)


Teflon tape seals just fine, but it won't take mains water pressure,


Of course it will. I've never had a Teflon tape joint leak. Where do
you live, the turbine hall of a hydroelectric dam?

Cheers

Phil Hobbs

Heh. I talk with many people who plumb, and on occasion do so myself. All our experiences are the same, don't use teflon tape to seal threads at mains pressure, it leaks. No problem with stored water & 4 floors of head.

I'm not saying it's not possible to get it to work, but at least with the plumbing fittings we use here, on mains it doesn't.


NT

 

[whit3rd]

On Monday, May 27, 2019 at 12:43:25 AM UTC-7, tabb...@gmail.com wrote:

> Heh. I talk with many people who plumb, and on occasion do so myself. All our experiences are the same,

No, they aren't. I've plumbed water and 10kpsi hydraulic fluid, and admittedly the
hydraulic fluid requires some extra work. But, white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

Works fine on compressed air, too.

 

[Bill Sloman]

On Monday, May 27, 2019 at 5:43:25 PM UTC+10, tabb...@gmail.com wrote:

On Sunday, 26 May 2019 23:53:04 UTC+1, Phil Hobbs wrote:
On 5/26/19 2:02 PM, tabbypurr wrote:
On Saturday, 25 May 2019 23:26:30 UTC+1, jurb...@gmail.com wrote:

Teflon tape is junk. It is an automatic leak. It is not code for
gas lines or any of that shit though the assholes at the DIYs will
try to tell you it is. Less diligent plumbers use it because it is
less messy than pipe dope.


The main question here is how much pressure you are dealing with.
If it is high then you might want to consider Locktite instead. I
know it is not the EXACT purpose of the shit but then do we care
what they wanted done with it once they got their money ? Fukum.

If you are involved with the possibility of any big liability here
I would do serious product testing before it goes out the door.

The problem with the pipe dope in your application is if the thing
is glass or glass supported then unscrewing it may break it.


Just what I am saying. Not the expert on LASERs n shit at all but I
have been involved with some weird kinda processes. The guy to ask
would have been the olman. he might have used like an alloy of
maybe mercury and tin, to have it solid at operating temperatures
but with a little Burnsomatic or maybe even a pencil torch you
could get it hot and take it back apart easily.. but it has to not
only well below the melting temperature, it also has to not cause
too much thermal expansion or it might break or deform.

I am assuming right now that you have a reason for that tape. The
way I see that is first of all that tape is white and quite
translucent. Duct tape would be better as a light shield. however
it has an aggressive adhesive so maybe not so good. Will masking
tape take the heat ? (only if you are dealing with any really
pressure of course)


Teflon tape seals just fine, but it won't take mains water pressure,


Of course it will. I've never had a Teflon tape joint leak. Where do
you live, the turbine hall of a hydroelectric dam?

Cheers

Phil Hobbs

Heh. I talk with many people who plumb, and on occasion do so myself. All our experiences are the same, don't use teflon tape to seal threads at mains pressure, it leaks. No problem with stored water & 4 floors of head.

I'm not saying it's not possible to get it to work, but at least with the plumbing fittings we use here, on mains it doesn't.

This seems to be one more case of NT being dogmatic when he's probably got the wrong end of the stick. My impression is that he isn't a reliable informant and is rather unwilling to even contemplate the idea that he might have got something wrong.

--
Bill Sloman, Sydney

 

On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

On Monday, May 27, 2019 at 12:43:25 AM UTC-7, tabby wrote:

Heh. I talk with many people who plumb, and on occasion do so myself. All our experiences are the same,

No, they aren't.

you haven't spoken to them

I've plumbed water and 10kpsi hydraulic fluid, and admittedly the
hydraulic fluid requires some extra work. But, white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Works fine on compressed air, too.

NT

 

[whit3rd]

On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabb...@gmail.com wrote:

On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can touch 'em up after they
get dirty, rusty or dinged), and a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes into the fitting.
Sometimes there's a drip or five, but that dries up by the next day.

Doesn't work on plastic fittings, though.

 

On Tuesday, 28 May 2019 09:40:02 UTC+1, whit3rd wrote:

On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabby wrote:
On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can touch 'em up after they
get dirty, rusty or dinged), and a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes into the fitting.
Sometimes there's a drip or five, but that dries up by the next day.

Doesn't work on plastic fittings, though.

I don't believe you would get our connectors watertight that way. No-one else has.


NT

 

[George Herold]

On Monday, May 27, 2019 at 5:33:56 AM UTC-4, whit3rd wrote:

On Monday, May 27, 2019 at 12:43:25 AM UTC-7, tabb...@gmail.com wrote:

Heh. I talk with many people who plumb, and on occasion do so myself. All our experiences are the same,

No, they aren't. I've plumbed water and 10kpsi hydraulic fluid, and admittedly the
hydraulic fluid requires some extra work. But, white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

Works fine on compressed air, too.

I use teflon tape on lotsa plumbing stuff. Even some pipe thread
hydraulic connections on my backhoe. No problems...
A plumber/ machinist once told me that the teflon doesn't really seal
as much as making the joint have less friction, so you can get the
pipe treads tighter. (I have no idea if that's true. Seems like
it may do a bit of both.)
Using teflon tape on a *non*- tapered seal is silly..
but I saw that a lot in grad school.

George H.

 

[George Herold]

On Tuesday, May 28, 2019 at 5:40:05 AM UTC-4, tabb...@gmail.com wrote:

On Tuesday, 28 May 2019 09:40:02 UTC+1, whit3rd wrote:
On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabby wrote:
On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can touch 'em up after they
get dirty, rusty or dinged), and a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes into the fitting.
Sometimes there's a drip or five, but that dries up by the next day.

Doesn't work on plastic fittings, though.

I don't believe you would get our connectors watertight that way. No-one else has.

Are they tapered seals? (pipe threads) or some other type.. compression,
o-ring... there are lots of joints for which teflon tape will not work.
GH

NT

 

On Tuesday, 28 May 2019 15:04:29 UTC+1, George Herold wrote:

On Tuesday, May 28, 2019 at 5:40:05 AM UTC-4, tabby wrote:
On Tuesday, 28 May 2019 09:40:02 UTC+1, whit3rd wrote:
On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabby wrote:
On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can touch 'em up after they
get dirty, rusty or dinged), and a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes into the fitting.
Sometimes there's a drip or five, but that dries up by the next day.

Doesn't work on plastic fittings, though.

I don't believe you would get our connectors watertight that way. No-one else has.
Are they tapered seals? (pipe threads) or some other type.. compression,
o-ring... there are lots of joints for which teflon tape will not work.

They're not tapered, and I've never met anyone get any sort of reliable seal with them using PTFE tape. Great at low pressures, but not mains water. It seems he's talking about a different type of plumbing joint. I noticed he mentioned them being rusty, but ours aren't normally steel. Torquing em up like a maniac doesn't stop them leaking.


NT

 

[Phil Hobbs]

On 5/28/19 1:19 PM, George Herold wrote:

On Tuesday, May 28, 2019 at 12:07:28 PM UTC-4, tabb...@gmail.com wrote:
On Tuesday, 28 May 2019 15:04:29 UTC+1, George Herold wrote:
On Tuesday, May 28, 2019 at 5:40:05 AM UTC-4, tabby wrote:
On Tuesday, 28 May 2019 09:40:02 UTC+1, whit3rd wrote:
On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabby wrote:
On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can touch 'em up after they
get dirty, rusty or dinged), and a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes into the fitting.
Sometimes there's a drip or five, but that dries up by the next day..

Doesn't work on plastic fittings, though.

I don't believe you would get our connectors watertight that way. No-one else has.
Are they tapered seals? (pipe threads) or some other type.. compression,
o-ring... there are lots of joints for which teflon tape will not work.

They're not tapered, and I've never met anyone get any sort of reliable seal with them using PTFE tape. Great at low pressures, but not mains water. It seems he's talking about a different type of plumbing joint. I noticed he mentioned them being rusty, but ours aren't normally steel. Torquing em up like a maniac doesn't stop them leaking.

OK that makes sense, teflon tape is only used (correctly) on tapered seals,
https://www.adaptall.com/info-tutorials/sealing-methods.php
(The first pic there.)
(The thrid.. tapered male into straight female, just seems like bad
form... no mater how attractive the straight female is. :^)

George H.


NT

Yup. All our threaded piping is NPT, precisely so you can torque it
till it doesn't leak. Why would anyone use a non-tapered pipe thread?
Is that really the standard over there?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[George Herold]

On Tuesday, May 28, 2019 at 12:07:28 PM UTC-4, tabb...@gmail.com wrote:

On Tuesday, 28 May 2019 15:04:29 UTC+1, George Herold wrote:
On Tuesday, May 28, 2019 at 5:40:05 AM UTC-4, tabby wrote:
On Tuesday, 28 May 2019 09:40:02 UTC+1, whit3rd wrote:
On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabby wrote:
On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can touch 'em up after they
get dirty, rusty or dinged), and a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes into the fitting.
Sometimes there's a drip or five, but that dries up by the next day..

Doesn't work on plastic fittings, though.

I don't believe you would get our connectors watertight that way. No-one else has.
Are they tapered seals? (pipe threads) or some other type.. compression,
o-ring... there are lots of joints for which teflon tape will not work.

They're not tapered, and I've never met anyone get any sort of reliable seal with them using PTFE tape. Great at low pressures, but not mains water. It seems he's talking about a different type of plumbing joint. I noticed he mentioned them being rusty, but ours aren't normally steel. Torquing em up like a maniac doesn't stop them leaking.

OK that makes sense, teflon tape is only used (correctly) on tapered seals,
https://www.adaptall.com/info-tutorials/sealing-methods.php
(The first pic there.)
(The thrid.. tapered male into straight female, just seems like bad
form... no mater how attractive the straight female is. :^)

George H.

NT

 

On Tuesday, 28 May 2019 18:27:16 UTC+1, Phil Hobbs wrote:

On 5/28/19 1:19 PM, George Herold wrote:
On Tuesday, May 28, 2019 at 12:07:28 PM UTC-4, tabby wrote:
On Tuesday, 28 May 2019 15:04:29 UTC+1, George Herold wrote:
On Tuesday, May 28, 2019 at 5:40:05 AM UTC-4, tabby wrote:
On Tuesday, 28 May 2019 09:40:02 UTC+1, whit3rd wrote:
On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabby wrote:
On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can touch 'em up after they
get dirty, rusty or dinged), and a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes into the fitting.
Sometimes there's a drip or five, but that dries up by the next day...

Doesn't work on plastic fittings, though.

I don't believe you would get our connectors watertight that way. No-one else has.
Are they tapered seals? (pipe threads) or some other type.. compression,
o-ring... there are lots of joints for which teflon tape will not work.

They're not tapered, and I've never met anyone get any sort of reliable seal with them using PTFE tape. Great at low pressures, but not mains water. It seems he's talking about a different type of plumbing joint. I noticed he mentioned them being rusty, but ours aren't normally steel. Torquing em up like a maniac doesn't stop them leaking.

OK that makes sense, teflon tape is only used (correctly) on tapered seals,
https://www.adaptall.com/info-tutorials/sealing-methods.php
(The first pic there.)
(The thrid.. tapered male into straight female, just seems like bad
form... no mater how attractive the straight female is. :^)

George H.

Yup. All our threaded piping is NPT, precisely so you can torque it
till it doesn't leak. Why would anyone use a non-tapered pipe thread?
Is that really the standard over there?

Cheers

Phil Hobbs

I guess that's like asking why would anyone use an Edison plug. Some things might be better changed but don't need to be, and there would be a downside to doing so.


NT

 

[Phil Hobbs]

On 5/28/19 5:09 PM, tabbypurr@gmail.com wrote:

On Tuesday, 28 May 2019 18:27:16 UTC+1, Phil Hobbs wrote:
On 5/28/19 1:19 PM, George Herold wrote:
On Tuesday, May 28, 2019 at 12:07:28 PM UTC-4, tabby wrote:
On Tuesday, 28 May 2019 15:04:29 UTC+1, George Herold wrote:
On Tuesday, May 28, 2019 at 5:40:05 AM UTC-4, tabby wrote:
On Tuesday, 28 May 2019 09:40:02 UTC+1, whit3rd wrote:
On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabby
wrote:
On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape
OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can
touch 'em up after they get dirty, rusty or dinged), and
a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes
into the fitting. Sometimes there's a drip or five, but
that dries up by the next day..

Doesn't work on plastic fittings, though.

I don't believe you would get our connectors watertight
that way. No-one else has.
Are they tapered seals? (pipe threads) or some other type..
compression, o-ring... there are lots of joints for which
teflon tape will not work.

They're not tapered, and I've never met anyone get any sort of
reliable seal with them using PTFE tape. Great at low
pressures, but not mains water. It seems he's talking about a
different type of plumbing joint. I noticed he mentioned them
being rusty, but ours aren't normally steel. Torquing em up
like a maniac doesn't stop them leaking.

OK that makes sense, teflon tape is only used (correctly) on
tapered seals,
https://www.adaptall.com/info-tutorials/sealing-methods.php (The
first pic there.) (The thrid.. tapered male into straight female,
just seems like bad form... no mater how attractive the straight
female is. :^)

George H.

Yup. All our threaded piping is NPT, precisely so you can torque
it till it doesn't leak. Why would anyone use a non-tapered pipe
thread? Is that really the standard over there?

Cheers

Phil Hobbs

I guess that's like asking why would anyone use an Edison plug. Some
things might be better changed but don't need to be, and there would
be a downside to doing so.

Well, Edison plugs don't leak a lot of electrons.

On the other hand you can't use them for shillelaghs like your big fused
things.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Lasse Langwadt Christense]

tirsdag den 28. maj 2019 kl. 19.20.05 UTC+2 skrev George Herold:

On Tuesday, May 28, 2019 at 12:07:28 PM UTC-4, tabb...@gmail.com wrote:
On Tuesday, 28 May 2019 15:04:29 UTC+1, George Herold wrote:
On Tuesday, May 28, 2019 at 5:40:05 AM UTC-4, tabby wrote:
On Tuesday, 28 May 2019 09:40:02 UTC+1, whit3rd wrote:
On Monday, May 27, 2019 at 11:16:42 PM UTC-7, tabby wrote:
On Monday, 27 May 2019 10:33:56 UTC+1, whit3rd wrote:

...white teflon tape works fine with domestic
plumbing (NPT thread) fittings. Even without tape OR pipe dope, you can get a seal.

I can't, so tell us how.

Clean, well-formed threads (I have taps and dies so I can touch 'em up after they
get dirty, rusty or dinged), and a couple of piipe wrenches. You need two for a
coupling, one to keep pipe #1 still while pipe #2 goes into the fitting.
Sometimes there's a drip or five, but that dries up by the next day.

Doesn't work on plastic fittings, though.

I don't believe you would get our connectors watertight that way. No-one else has.
Are they tapered seals? (pipe threads) or some other type.. compression,
o-ring... there are lots of joints for which teflon tape will not work.

They're not tapered, and I've never met anyone get any sort of reliable seal with them using PTFE tape. Great at low pressures, but not mains water. It seems he's talking about a different type of plumbing joint. I noticed he mentioned them being rusty, but ours aren't normally steel. Torquing em up like a maniac doesn't stop them leaking.

OK that makes sense, teflon tape is only used (correctly) on tapered seals,
https://www.adaptall.com/info-tutorials/sealing-methods.php
(The first pic there.)
(The thrid.. tapered male into straight female, just seems like bad
form... no mater how attractive the straight female is. :^)

yes, anything but tapered should be sealed with o-rings or a gaskets

the disadvantage with teflon tape is that it cannot be adjusted or only very limited so you only get one chance to get angles right

 

On Wednesday, 29 May 2019 00:31:22 UTC+1, Phil Hobbs wrote:

On 5/28/19 5:09 PM, tabbypurr wrote:
On Tuesday, 28 May 2019 18:27:16 UTC+1, Phil Hobbs wrote:

Yup. All our threaded piping is NPT, precisely so you can torque
it till it doesn't leak. Why would anyone use a non-tapered pipe
thread? Is that really the standard over there?

Cheers

Phil Hobbs

I guess that's like asking why would anyone use an Edison plug. Some
things might be better changed but don't need to be, and there would
be a downside to doing so.

Well, Edison plugs don't leak a lot of electrons.

Hmm. You get a lot more electrical fires than we do.

On the other hand you can't use them for shillelaghs like your big fused
things.

Cheers

Phil Hobbs

I think their main use is for standing on. They tend to sit pins up, so that's fun.


NT

 

[whit3rd]

On Tuesday, May 28, 2019 at 10:20:05 AM UTC-7, George Herold wrote:

OK that makes sense, teflon tape is only used (correctly) on tapered seals,
https://www.adaptall.com/info-tutorials/sealing-methods.php
(The first pic there.)
(The thrid.. tapered male into straight female, just seems like bad
form... no mater how attractive the straight female is. :^)

Tapered (NPT) mates poorly with straight (NPS) threads, but with the NPS
(male or female) to start with, it's easy to convert it to NPT with a pipe tap or die
(and I've had to do it a few times). The only NPS that can't be reworked
is a stub female socket (you'd need to bore a deeper hole in the socket).

Teflon tape IS a good antiseize lube
for anything that can get hot/wet/frozen. Broke some waterpump
fasteners after they rusted/galled/froze in place, gave the replacements a wrap
of the PTFE tape to keep oxygen and moisture away from the
helical bits that should slide.

 

[Phil Hobbs]

On 5/29/19 2:16 AM, tabbypurr@gmail.com wrote:

On Wednesday, 29 May 2019 00:31:22 UTC+1, Phil Hobbs wrote:
On 5/28/19 5:09 PM, tabbypurr wrote:
On Tuesday, 28 May 2019 18:27:16 UTC+1, Phil Hobbs wrote:

Yup. All our threaded piping is NPT, precisely so you can torque
it till it doesn't leak. Why would anyone use a non-tapered pipe
thread? Is that really the standard over there?

Cheers

Phil Hobbs

I guess that's like asking why would anyone use an Edison plug. Some
things might be better changed but don't need to be, and there would
be a downside to doing so.

Well, Edison plugs don't leak a lot of electrons.

Hmm. You get a lot more electrical fires than we do.

Not so you'd notice. From net searches, it seems as though you folks
have about 6000-7000 electrical fires a year, and we have about 28000.
Since the US has about five times the population of the UK, we may even
be a bit ahead.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com