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whipper_snapper
01-10-08, 11:38
What is the collective wisdom on the use of jointing compound or ptfe tape for use on a compression join in a boat's gas supply ?

Calor Marine say:

[ QUOTE ]
The addition of jointing compound to compression joints is totally unnecessary, in fact applying a sealant could give a false impression of sealing the joint when the compression nuts may be only hand tight. It can also prevent the olive from engaging properly with the coupling body. The resulting shrinkage of the sealant would lead to a leak.

[/ QUOTE ]

But they sell a "Gas Seal Jointing Compound"

Thanks

LORDNELSON
01-10-08, 11:54
I recently had the gas installation upgraded on my boat. The Marine Corgi fitters used PTFE tape on some joints and when I queried this they pointed out that it was PTFE with a "G" after it signifying that it was PTFE made specially for gas use.

BobnLesley
01-10-08, 11:58
I have/use (about once every two years) a tube of red sealant made specifically for gas piping - never had a joint fail to seal. If you choose to go for PTFE tape, make sure you get the gas specific one.

Beat me to it Lord N /forums/images/graemlins/ooo.gif

pete
01-10-08, 12:10
Been in domestic gas and central heating for almost 40 years years and have tried both with and without non setting jointing paste, and do prefer, on water and gas to put a tiny smear on the olives It does help to lubricate the joint and stop that horrible squeal sound you some times get. I never wrap olives with ptfe tape but some people do. no doubt some one with more experience of this will disagree.
/forums/images/graemlins/ooo.gif pete

earlybird
01-10-08, 13:42
I'd regard the primary use of sealants and tape as being for joints in which the threads themselves form the seal, ie taper threads. Compression fittings don't really need them, although, as Pete says, a smear does no harm, provided the olive is in good condition. What is a no-no is using them to try to seal a damaged/abused compression fitting.

starboard
01-10-08, 13:48
This is the stuff I use, that said if its a very course thread I use gas standard PTFE tape but on a taper thread use the Bonner "Gas-Tite"

http://marinestore.co.uk/Merchant2/merch...t_Code=MD100890 (http://marinestore.co.uk/Merchant2/merchant.mvc?Store_Code=mrst&Screen=PROD&Product_C ode=MD100890)

Paul.

colvic987
01-10-08, 14:13
should be able to find the 'gas tite' compound at a plumbers merchants, and get a can of detector solution whilst your there, so you can check the joints are 100% leakproof..

LittleShip
01-10-08, 14:35
Been in domestic gas and central heating for almost 40 years ........
no doubt some one with more experience of this will disagree.

Just how old do you think we are on here! /forums/images/graemlins/smile.gif

Tom

narooma
01-10-08, 14:52
Just how old do you think we are on here!

When people had real jobs they started at sixteen and retired at 65 ...he has a few years to go yet (I hope)

Alfie168
01-10-08, 17:38
We use Plumb Center "Jet Blue Plus"...its not a jet, its not blue..and as far as I can see exactly the same as the old Jet Blue without the Plus.

Yes yes yes...technically speaking sealants are not necessary on compression joints, but then who is going to guarantee to make every joint perfectly.

Use a smear on the lip of the fitting where the olive seats, Saves a lot of bother and its good insurance.

The company I work for is responsible for the gas installations in over 100,000 domestic dwellings. We would use sealant on all compression fittings in addition to threaded fittings. We tend not to use PTFE tape, but I can't give you a reason for that other than cost possibly.

Tim

VicS
01-10-08, 20:14
PTFE tape for tapered joints only. A jointing compound can be used instead. There is a special grade of tape for gas.

Parallel threaded joints should tighten down onto a joint washer.

Compression fittings should not use either. Definitely not tape.
Calor say use copper olives not brass ones.

See THIS PAGE (http://www.calormarineshop.co.uk/boat_diy/compression_fitting.htm) on the Calormarine website for instructions on using compression fittings.

pete
01-10-08, 21:35
[ QUOTE ]

Just how old do you think we are on here! /forums/images/graemlins/smile.gif

Tom

[/ QUOTE ]

Hi Tom don't forget we have met. /forums/images/graemlins/wink.gif

Pete

Malcb
01-10-08, 22:27
As an ex British Gas Service & Marketing Manager you shouldn't need to put anything on a compression fitting. Ensure that the olive is new and the connection is made in the prescribed manner and the joint will be satifactory.

PTFE tape is very good for making up joints on tapered fittings, in particular water fittings, but not olive compression joints, where there should be no need with either gas or water.

For instance, if you are fitting a tap to a pipe and want the tap (obviously) to finsih up in a particular plane after tightening it up to the joint, then PTFE tape is perfect for ensuring that the joint is perfect afetr tightening up the joint.

For testing you can make up your own soap solution, it's merely water with some detergent added. Neat detergent is no good as it doesn't 'bubbel' easily enough.

VicS
01-10-08, 22:34
[ QUOTE ]
For testing you can make up your own soap solution, it's merely water with some detergent added. Neat detergent is no good as it doesn't 'bubbel' easily enough

[/ QUOTE ]

In the past we have been told not to use ordinary detergent solution , at least not washing up liquid solution, because it is corrosive. We have all spent our hard earned dollars on the sprays .

LittleShip
02-10-08, 08:39
Hi Tom don't forget we have met.

Oh I know we have you old person you! /forums/images/graemlins/smile.gif

Tom