Roysie
Member
I am in the process of fitting an Eberspacher to my boat and would like to know what to use, if anything on a compression fitting in the diesel fuel line.
Diesel Jointing compound
- Thread starter Roysie
- Start date
sailorman
Well-Known Member
isnt it supplied with a rubber interconnecting hose /forums/images/graemlins/confused.gif
pennycar9
Well-Known Member
Stag 1 or 2 is the best compound for oil,been around for years, and to my mind cannot be equalled. Your can get it from any good plumbers merchants.
Poignard
Well-Known Member
Compression fittings shouldn't need any jointing compound - if they do something is wrong with the fitting or the fitter.
alan17
Well-Known Member
Dry. Secret is not to over tighten. Just nip up then if there is a leak tighten just a little more. If you over tighten to start with you will never get a seal.
pennycar9
Well-Known Member
if you put a little compound on to start with you will neither have a leak or have to over tighten.
pennycar9
Well-Known Member
So why did they produce jointing compound in the first place. I have been using jointing compound on differing joints for years. Wether it be Boss white on heating systems, Boss blue on potable water, Rocol Gastite on, you've got it, Gas,or Stag 1 or2 on oil or oil derivitives. Wether it be a face to face joint or a compression fitting, they all get a little smear. Nothing wrong with the fitter in this case.The latest stuff on the market is a PTFE paste, it is as much good as the PTFE Tape, IE as much good as a chocolate fireguard. In my opinion,and I stand ready to be shot down in Flames, by people who know what they are talking about!!!!!!.
Poignard
Well-Known Member
[ QUOTE ]
From the Calor Marine website:
A compression fitting is the most commonly used joint when fitting out a boat gas system. They use an olive which is compressed to make the gas tight joint. If assembled correctly, ensure a perfect seal, which can be dismantled and re made. The addition of jointing compound, to ensure a seal, is totally unnecessary.
Indeed, applying a sealant could give a false impression of sealing the joint when the compression nuts may be only hand tight; also the jointing compound will prevent the olive from engaging properly with the coupling body. The resultant shrinkage of the sealant would lead to a gas leak.
[/ QUOTE ]
From the Calor Marine website:
A compression fitting is the most commonly used joint when fitting out a boat gas system. They use an olive which is compressed to make the gas tight joint. If assembled correctly, ensure a perfect seal, which can be dismantled and re made. The addition of jointing compound, to ensure a seal, is totally unnecessary.
Indeed, applying a sealant could give a false impression of sealing the joint when the compression nuts may be only hand tight; also the jointing compound will prevent the olive from engaging properly with the coupling body. The resultant shrinkage of the sealant would lead to a gas leak.
[/ QUOTE ]
pennycar9
Well-Known Member
Oh! and there's me thinking the post was about oil!!!!! Normally a compression fitting is supplied with a brass olive which is hard and really could do with a little compound. Copper olives.on the other hand, especially if they are annealed, are much softer and possibly do not need the compound as they compress better, but what the hell, a little compound dosnt hurt, especially as Stag stays soft!!!!
Poignard
Well-Known Member
Sorry! I left out the next bit of Calormarine's recommendations:
[ QUOTE ]
When making compression joints, Calor recommends the use of <u>soft copper olives</u>. These olives are easier to compress and therefore easier to produce a good seal. Brass olives, which are harder, become brittle in use and the joint can leak or fail at the point where the brass olive engages the coupling body.
[/ QUOTE ]
[ QUOTE ]
When making compression joints, Calor recommends the use of <u>soft copper olives</u>. These olives are easier to compress and therefore easier to produce a good seal. Brass olives, which are harder, become brittle in use and the joint can leak or fail at the point where the brass olive engages the coupling body.
[/ QUOTE ]
pennycar9
Well-Known Member
I stand corrected. I am now on my way to the local cemetary to dig up the ba--ards who told me all those lies when I was apprenticed to them.Just goes to show, dont believe a word all those tradesmen told you.
Poignard
Well-Known Member
I supose it all depends where you are trained. When I was trained in the Royal Navy and at South Shields Marine and Engineering College etc. I was taught that sealants should not be used on compression fittings. I was told why and it made sense then and it makes sense now. That is why I don't use sealant on compression fittings.
Why do you think you know better than the specialist engineers who design and manufacture compression fittings? I've spent many hours of my life repairing the damage caused by botchers who ruin valuable equipment using the wrong tools and techniques, all because they think they know best.
By the way, you sarcastically ask what "jointing compound" is for, and mention Stag. I'll tell you. It is intended for screwed pipe joints together with a small amount of hemp. Nowadays PTFE thread sealant or PTFE tape is often used instead.
Anyway, I'm bored with this exchange and I've got a living to earn, so if you'll excuse me I'll leave you to enjoy the last word.
/forums/images/graemlins/grin.gif
Why do you think you know better than the specialist engineers who design and manufacture compression fittings? I've spent many hours of my life repairing the damage caused by botchers who ruin valuable equipment using the wrong tools and techniques, all because they think they know best.
By the way, you sarcastically ask what "jointing compound" is for, and mention Stag. I'll tell you. It is intended for screwed pipe joints together with a small amount of hemp. Nowadays PTFE thread sealant or PTFE tape is often used instead.
Anyway, I'm bored with this exchange and I've got a living to earn, so if you'll excuse me I'll leave you to enjoy the last word.
/forums/images/graemlins/grin.gif
sailorman
Well-Known Member
i still have the tin of "Osotite" that your tradesman gave me 40 yrs ago /forums/images/graemlins/grin.gif
pennycar9
Well-Known Member
Thats killed that one off then.
stephenh
Well-Known Member
Interesting -
I was taught by a time served plumber who said "the manufacturers instructions state 'use light machine oil and nothing else'"
and this is what I have always done - don't do much these days..
However, checking it out and updating myself I came across the following :
http://www.peglerhattersleylogistics.com/Media/EN/Downloads/15263411_6Compression_Fittings.pdf
Apply a light oil to the threads and chamfers
where possible. This will reduce assembly torque
and minimise the risk of damage. This is essential
on sizes above 28mm.
If a sealant is required, use a suitable PTFE
based compound, eg Loctite 577 or PTFE tape.
So it appears that everybody is right !!!
I was taught by a time served plumber who said "the manufacturers instructions state 'use light machine oil and nothing else'"
and this is what I have always done - don't do much these days..
However, checking it out and updating myself I came across the following :
http://www.peglerhattersleylogistics.com/Media/EN/Downloads/15263411_6Compression_Fittings.pdf
Apply a light oil to the threads and chamfers
where possible. This will reduce assembly torque
and minimise the risk of damage. This is essential
on sizes above 28mm.
If a sealant is required, use a suitable PTFE
based compound, eg Loctite 577 or PTFE tape.
So it appears that everybody is right !!!
sailorman
Well-Known Member
OIL & GAS /forums/images/graemlins/blush.gif
PeterGibbs
Well-Known Member
For the benefit of other posters I want to endorse your view. It's an important topic.
I put it to thinking folks this way - manufacturers of systems have a vested interest in producing simple and effective jointing systems. So the jointing of pipes and conduits should be staightforward and need no additional materials. This way, dismantling is relatively simple, and mess is avoided. Bunging PTFE tape onto every joint has no place in properly installed systems, and raises questions as to the integrity of the finished job. If the materials being jointed are not precisely suited, whacking on tape is a poor solution - some would call it a bodge!
So using gunk on joints should be the exception not the rule, but they are useful when, for whatever reason, they help get us home. However, no matelot would be happy to go to sea with vital system joints held together by emergency fixes, when remaking dry in recommended materials is clearly the better solution.
So fuel joints should be dry compression. Gas should be dry too. Water should be push fit or soldered.
To dissenters I say, which vessel would you prefer to go to sea on - the PTFE special or the other?
PWG
I put it to thinking folks this way - manufacturers of systems have a vested interest in producing simple and effective jointing systems. So the jointing of pipes and conduits should be staightforward and need no additional materials. This way, dismantling is relatively simple, and mess is avoided. Bunging PTFE tape onto every joint has no place in properly installed systems, and raises questions as to the integrity of the finished job. If the materials being jointed are not precisely suited, whacking on tape is a poor solution - some would call it a bodge!
So using gunk on joints should be the exception not the rule, but they are useful when, for whatever reason, they help get us home. However, no matelot would be happy to go to sea with vital system joints held together by emergency fixes, when remaking dry in recommended materials is clearly the better solution.
So fuel joints should be dry compression. Gas should be dry too. Water should be push fit or soldered.
To dissenters I say, which vessel would you prefer to go to sea on - the PTFE special or the other?
PWG
stephenh
Well-Known Member
Sailorman - fair play - my quotes are for water - whoops - how do you put those 'I am embassed' signs up ?
/forums/images/graemlins/blush.gif
ah - done it !
/forums/images/graemlins/blush.gif
ah - done it !
Dazedkipper
Well-Known Member
Jointing compound called 'Heldite' is used in fuel industry.
Poignard
Well-Known Member
[ QUOTE ]
Jointing half-hard thick walled R250
copper tube
This copper tube is significantly thicker than
other varieties – refer to Table 1 on page 8 for
specifications. Special care needs to be taken
during installation. Follow steps one to three
opposite, but with the following additional
precautions:
Ensure pipework is supported during and after
installation, as thick-walled copper tube is less
tolerant of stress on the joints. The pipework
should be clipped as close as possible to the
fittings, particularly where long runs are involved.
Use spanners of the correct size and length.
More torque is required to tighten Kuterlite fittings
with thick walled copper tube, and care should be
taken to ensure neighbouring joints are not
disturbed.
Apply a light oil to the threads and chamfers
where possible. This will reduce assembly torque
and minimise the risk of damage. This is essential
on sizes above 28mm.
If a sealant is required, use a suitable PTFE
based compound, eg Loctite 577 or PTFE tape.
[/ QUOTE ]
Please do correct me if I'm wrong but I think the section you have quoted, from the Kuterlite manual [page 14 or thereabouts], is for half-hard thick-walled copper tube which is not the type normally used for fuel and gas lines on small pleasure craft.
Jointing half-hard thick walled R250
copper tube
This copper tube is significantly thicker than
other varieties – refer to Table 1 on page 8 for
specifications. Special care needs to be taken
during installation. Follow steps one to three
opposite, but with the following additional
precautions:
Ensure pipework is supported during and after
installation, as thick-walled copper tube is less
tolerant of stress on the joints. The pipework
should be clipped as close as possible to the
fittings, particularly where long runs are involved.
Use spanners of the correct size and length.
More torque is required to tighten Kuterlite fittings
with thick walled copper tube, and care should be
taken to ensure neighbouring joints are not
disturbed.
Apply a light oil to the threads and chamfers
where possible. This will reduce assembly torque
and minimise the risk of damage. This is essential
on sizes above 28mm.
If a sealant is required, use a suitable PTFE
based compound, eg Loctite 577 or PTFE tape.
[/ QUOTE ]
Please do correct me if I'm wrong but I think the section you have quoted, from the Kuterlite manual [page 14 or thereabouts], is for half-hard thick-walled copper tube which is not the type normally used for fuel and gas lines on small pleasure craft.
