CAN YOU USE PTFE TAPE ON GAS CYLINDER CONNECTION? (1 Viewer)

[Terry]

I hope your response is not aimed at me as an unqualified engineer. Go to gas safe and look up 040927 and you will see I am a fully qualified engineer in natural gas LPG propane / butane/ and have been for 30 years. I understand the working pressure of natural gas and LPG .
If you do not want to take the information on board that is your problem,
You are all dealing with a gas more dangerous than natural gas with no qualifications.
Don't want to enter into an argument with funsters about gas issues but you are messing about with a potential explosion.
I am qualified in leisure accommodation vehicles,park homes ,in both NG & LPG.
Not trying to be clever but that is what I do for a living.

We are not arguing we are having a discussion I said right in my first post I did not agree with Jim but I did say in original post I stand to be corrected and it would not be the first time I have been wrong Still cannot see the harm it would do or (dare I say this ) no better not I will bow to public opinion
terry

 

[timdownieuk]

Blimey! I've really set one running here!!

As an aside, I road tested the new travelling gas BBQ out tonight. You'll be pleased to know that as advised, I used NO tape, gunk or jointing compound! Got a cylinder out of the van, linked it up to the BBQ, gave the nut plenty of Newtons with a spanner, checked for leaks with brush and washing up liquid (yeah I know someone here advised against, but that was the manufacturers destructions) and hey presto - no gas smell.

I did notice however that even when I got the brand new regulator and hose out of the box, it seemed to smell. Maybe I'm confusing gas smells with rubber?

I'm not sure that "plenty of newtons" is necessary but it's hard to find a quoted tightness for gas bottle couplings. Even Calor's own site simply says "Make sure the gas bottle connection is tight" which seems rather vague.

My own feeling is that over-tightening isn't a good idea and I've never striven to give a connection "plenty of newtons".

Any LPG qualified fitters care to comment? Does such a thing and a "torque spanner" exist?

Tim

 

[tofo]

Thing is if you apply a jointing paste to the mating faces
They will probably seal

But if the joint is broken at a later date
Then a connection to a different piece of equipment
Eg Truck to garden BBQ
Then you have a chance of uneven mating faces
Depending if the joint compound has hardened

And then you exchange the bottle
The seal for the next user of that bottle
May be compromised
So ground faces no ptfe or joint compound
In my opinion

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[Plumberman]

Hi Terry ,not been argumentative but as a gas engineer do feel a bit passionate about the thread.
If I come across as as argumentative I apologise ,
I am interested in all our funsters safety more than anything.
Please take great care if you are involved in any gas work on Your motorhomes .
Check for leaks using leak detection fluid every time you break a gas connection.
LPG is one of the most dangerous gasses used by the general public without any training.
Not trying to be a killjoy.
Please be careful all of you who do your own gas repairs.
Alex.

 

[Plumberman]

Hi Wingman
The rubber hoses do have quite a smell about them.
Will fade in time.

 

[Plumberman]

Hi Tofu
Modern gas sealants do not set or harden so no problems connecting to new appliances.

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[Terry]

Hi Terry ,not been argumentative but as a gas engineer do feel a bit passionate about the thread.
If I come across as as argumentative I apologise ,
I am interested in all our funsters safety more than anything.
Please take great care if you are involved in any gas work on Your motorhomes .
Check for leaks using leak detection fluid every time you break a gas connection.
LPG is one of the most dangerous gasses used by the general public without any training.
Not trying to be a killjoy.
Please be careful all of you who do your own gas repairs.
Alex.

No problem Alex I check and pressure test all my gas and water bits and on my own van I have a gas low gauge that I turn on and off then leave for ten mins to see if it is still holding pressure -I understand it's only the pressure in the bottle but good enough to check if there's a leak --As to changing a gas bottle
terry

 

[Plumberman]

I am not a know all ,far from it ,just be safe ,thanks to all of you for listening ,

 

[Gromett]

Just trying to figure out this thread. @Plumberman and @ScotJimland appear to be saying the same thing but disagree with each other?

As I said I was always told never to use PTFE on gas fittings, no reason given or required. The people I asked are people I seriously trust.

My training from my apprenticeship days persuades me to conclude that PTFE is a way of bodging something rather than making sure it is done right.

For me, PTFE is a way of reducing friction so you can tighten stuff up more. It is not a means of "bodge fixing" defects on the surface of a connector that otherwise wouldn't need it.
With water I would use it to force a connection if absolutely necessary under the sure knowledge that wet feet was the worst consequence. With gas I am sorry but no thanks. And yes I do carry a reel of it in my van but it is still unopened.

None of the gas connectors in a motorhome whether compression fittings or POL are designed to need PTFE in their installation. If your fitting needs it I would class it as faulty. I don't think it is wise to keep Faulty gas fittings in a van no matter how well you have bodged it.

PS: I am not an expert on this in any way shape or form and don't profess to be. Just my opinion.

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[Plumberman]

Thanks Gromett for your reply.
Unfortunately we should not need PTFE on any threads but we buy from china and others which means threads are not as accurate as they should be,
So we need thread tapes to take up the inaccuracies due to machining.
If BSP was standard we would have no problem.
Tapered threads should eradicate the need for PTFE but unfortunately most of our fittings are parallel threads which require a form sealant..
Thanks
Alex.

 

[Gromett]

Thanks Gromett for your reply.
Unfortunately we should not need PTFE on any threads but we buy from china and others which means threads are not as accurate as they should be,
So we need thread tapes to take up the inaccuracies due to machining.
If BSP was standard we would have no problem.
Tapered threads should eradicate the need for PTFE but unfortunately most of our fittings are parallel threads which require a form sealant..
Thanks
Alex.

I am a little confused? When you say "But we buy from china" are you on about your work or motorhome gas jobs now?

The threads on my regulator and other fittings have been spot on. At work we used to cut/thread and finish all our own pipes. Never bought a thing from China

Are you saying PTFE in a motorhome is acceptable or should never be used?

 

[timdownieuk]

Thanks Gromett for your reply.
Unfortunately we should not need PTFE on any threads but we buy from china and others which means threads are not as accurate as they should be,
So we need thread tapes to take up the inaccuracies due to machining.
If BSP was standard we would have no problem.
Tapered threads should eradicate the need for PTFE but unfortunately most of our fittings are parallel threads which require a form sealant..
Thanks
Alex.

You seem to be contradicting yourself here. In a parallel threaded fitting surely the sealing occurs at the face, not around the threads. The threads are there to provide the face compression force. If you have a leak from the face then using PTFE tape to stop it leaking along the threads is surely a bodge?

Just to clarify another point, another poster has said that PTFE tape can ONLY be used on tapered threads. Who is right? This last message of yours has really confused me.

Tim

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[Terry]

After reading all this I am going back to the old ways Sod all these push fitting,compression joints etc, give me the old rubber pipe and jubilee clip for the gas and the hose and clips for the water -that way I can safely use the old washing up liquid and water mix without causing any damage Oh shit I forgot about connecting the gas bottle to the van better stick with the proper gas leak spray -
-Tecno if your reading this that nice shinny new SS flex pipe is no good it's got a rubber sealing end and a washer at the other end -I want my money back -it's no use or I'll be bodging- Us self builder's don't bodge we modify
terry

 

[Plumberman]

How can I buy my work from china! I am talking about imported fittings sold to the industry via imported items to the gas and plumbing trade which are substandard but still sold to the trade .
I am not saying PTFE should not be used in motorhomes,where did I say that?
PTFE is used on threaded pipe work only not as a alternative to bodge a job.
You might think you have bought nothing from china but you will be surprised what fittings are imported from China.
Also where did I say I had done work on motorhome gas jobs?
If your regulator threads and pipe work threads are spot on what's your problem?
You certainly don't need PTFE .

 

[timdownieuk]

Hi Wingman,
PTFE tape should not be used on Gas Unions as there is a risk if it stopping the two machined faces of the union sealing properly.
.

I am not saying PTFE should not be used in motorhomes,where did I say that?
.

Still confused.

Tim

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[Plumberman]

Hi Tim,
Sorry if I am causing confusion.
All I was trying to explain is if we use the correct fittings for gas installations then there should be no need for PTFE tape.
People mix and match water and gas fittings and parallel / tapered threads which creates the need for PTFE tape.
A good example is if you look at your domestic gas meter installation you will see no PTFE tape on any of the threaded joints just jointing paste because they have used the correct threads and fittings.
Alex

 

[scotjimland]

LPG installations should only be tackled by competent people who don't need to ask the most basic questions.. same applies to 12v and 230v electrical systems.

The OP asked a simple question about a leak with a bottle regulator, should he use PTFE tape .. the answer and explanation was given.

if you have any doubts about, or don't understand LPG gas fitting and the correct uses for PTFE tape, my advice is to leave it to the qualified..

I've no more to add, it's all been explained by several posters..

 

[Theonlysue]

Hope kiwicoss is reading this.
Him and his wife have experience of gas explosion.
From what I understand her hearing is damaged apart from the van!
And they may be lucky to be alive.
Not worth a bodge I think

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[Terry]

Lets all send for a qualified LPG man to change the gas bottle --oooop here in the north that will be about 30 quid call out charge but for you southerners it will be more like 1oo quid How the hell did we get from safe to use PTFE to a van exploding and bodging --I suspect the van exploding came about by owners not checking for gas leaks --harsh ? sorry if I have offended anyone
terry

 

[Wildman]

It seems people are missing the point. A leak free gas connection on a gas bottle is dependent on the cleanliness of the domed end and the mating receptacle on the bottle. The male connector is designed to be clamped against the female receptacle by the retaining nut it is the mating that makes the seal and no amount of PTFE will make any difference. iIn fact the lubrication it provides can allow over tightening and eventual stripping of the thread. little more than hand pressure is required to make the mating faces gas tight.

 

[Gromett]

How can I buy my work from china! I am talking about imported fittings sold to the industry via imported items to the gas and plumbing trade which are substandard but still sold to the trade .
I am not saying PTFE should not be used in motorhomes,where did I say that?
PTFE is used on threaded pipe work only not as a alternative to bodge a job.
You might think you have bought nothing from china but you will be surprised what fittings are imported from China.
Also where did I say I had done work on motorhome gas jobs?
If your regulator threads and pipe work threads are spot on what's your problem?
You certainly don't need PTFE .

@Plumberman I wasn't having a go, I am just confused as to your position on PTFE in motorhomes and was trying to clarify for my own interest nothing more.
You and @ScotJimland seem to be the ones with the most expertise in this area. I installed copper pipe in my van using compression joints all the way to the regulator. from there it is a pig tail to the gas bottle. The gas bottle isn't a POL connector just a threaded male connector. I haven't used any PTFE and have had no leaks. Am I just lucky or should I have been using PTFE.

I believed that using PTFE in this situation would be a bodge for this use case? I am just trying to get your expert opinion on it?

I am sorry if my post wasn't clear and caused you to think I was having a go .

PS: I did the EITB course as part of my apprenticeship many many moons ago. This involved a fitters course amongst other stuff. So we were taught how to cut, thread and prepare pipe works ranging from electrical conduit up to I think 10" steel high pressure pipes. I don't recall us using PTFE back then, if the thread wasn't good enough we got told to do it again. We did however use some type of greasy substance, can't remember what it was, but copperish/green in colour from memory, but this was only on final fit ready for testing.

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[Plumberman]

Hi Gromett,
I don't think you were having a go at me,it all got a bit confusing and we all went off the thread a bit. (no pun intended )
Your cylinder connection should be a male thread with a dome type fitting on the end.
This should seal to the cylinder valve without the use of PTFE .
You have connected correctly and have no leaks so you are not lucky you have used the fitting the way it was designed to be used.
Just make sure it is clean and undamaged and you should have no problems and do test the fitting for leaks when you change your cylinder.
I am saying this assuming you have got a proper cylinder union fit for purpose,ie LPG
My comment on cheap imported fittings was through personal experience and working with them,finding them to be poor quality
compared the dearer British Standard ones.
PTFE is a good product and can be used on threads if required so long as it is a PTFE suitable for LPG gas.
A lot of engineers use it on everything when they don't really need to.
I suppose a belt and braces approach.
Hope this is a help to you.
Alex

 

[Gromett]

Alex, I have a Gaslow cylinder. It doesn't have the POL fitting. It looks more like a screw on Butane fitting than the POL Propane fitting.

 

[Techno]

The washer is the seal
Black at the bottle end and red at the regulator end

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[Plumberman]

Hi Gromett.
I assume you are using propane not butane refillable cylinders.
All cylinders are fitted with wheel valves with a pol female left hand thread.
Regulators or high pressure hoses connecting to this also have a complimentary pol left handed connection.
It is not possible to connect a propane pol connector to a butane pol connector.
If you are unsure disconnect and seek advice from a qualified person.
Does your gaslow conecting hose have washers to form a seal?
I think gaslow connecting hoses use two female nuts .
Do you have the Gaslow filling kit with the stainless steel non rubber filler hoses
Can you post a picture?

 

[Techno]

Gaslow gasit etal use a butane connection regardless of the use of LPG
As I said black washer bottle end red or ocre washer at regulator

 

[Techno]

BTW There is a readily available adapter to connect a POL end to a butane connection
About £8

Edit Broken Link Removed

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[vwalan]

lots of continental bottles use the same connector for butane /propane .
some use a 50mbr system . some a 30mbr system . many use our pressure system .
its a shame there isnt one system . mind even autogas fillers should be one system .
its a strange world really .

 

[scotjimland]

lots of continental bottles use the same connector for butane /propane .
some use a 50mbr system . some a 30mbr system . many use our pressure system .
its a shame there isnt one system . mind even autogas fillers should be one system .
its a strange world really .

are you mad ?

do you want to put all these people who manufacture adapters out of business..

 

[vwalan]

save us carrying a bag of adaptors etc when visiting several countries .
i use most through a uk butane reg . abroad i try and get butane .
spanish /portugese i adapt with a repsol fitting to camping gas then to the butane fitting .
some regulators dont fit some foreign bottles they have a slightly different bottle fitting but fortunately the reg i have fits all.
makes you laugh most bottles used to be made in portugal , usually the bottles are the same they just adapt in the factory to where its going .

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