[Shop-talk] CSST gas fittings

[Mark Miller]

Sorry, I was unclear.  I bought some that had a heavy metal ring, placed 
on the first corrugation, that held the nut on.  With that design the 
cut end of the tube butted against a deformable gasket on the 'fixed' 
end of the fitting.  Instruction then said to torque the nut down fairly 
hard (60 ft-pounds?).  The second set sound like the one you discussed: 
split ring to hold the nut on, 5 corrugations back.  Metal ring next, 
then the o ring.  The cut end of the pipe was not the sealing surface: 
it is the o ring against the metal ring and the end of the fixed fitting 
half.  I am guessing that design replaced the first one.

Regards,

Mark Miller
markmiller at threeboysfarm.com

On 2/23/2018 5:27 AM, Arvid wrote:
> Having recently put in 5 or 6 of these from Menards, both 1/2 and 3/4 
> inch, and if my memory is any good, the incantation was:
>
> Cut end as clean as possible. I did use a file on several of them to 
> smooth out the jags and sharp edge that seemed inevitable when I cut 
> it with a pipe cutter.
>
> Strip yellow jacket to reveal 5 indentations.
>
> Put nut on tubing.
>
> Put metal ring on tubing.
>
> Put o-ring on tubing.
>
> Make sure gasket was still in the receiving side of the fitting.
>
> Put together and tighten nut no more than 1/2 turn.
>
> None of them leaked.
>
> There was the o-ring plus a gasket that was in the base of the 
> receiving side of the fitting to seal it. The gasket would be where 
> the cut end of the tubing would butt up against to make a seal. Plus 
> the o-ring to seal around the tubing.
>
> Your description of the first one seems to only have the gasket on the 
> receiving side and your description of the second one suggests it only 
> had the o-ring. All of mine had both, which seems to make sense.
>
> Arvid
>
>
> On 2/22/2018 10:55 PM, Mark Miller wrote:
>> So I just put in some flexible gas piping with CSST fittings. One 
>> leaked.  I took it apart and replaced the fitting and all is OK but: 
>> the new fitting is a very different design from the first. First 
>> sealed the end of the tube to a surface on the connector, whole thing 
>> held together by pressure against a ring you crimp into the 
>> corrugations of the tube.  The replacement uses an o ring to seal it 
>> all, so to the sides of the tube.  Which is newer? Which is 
>> preferred? Or should I avoid this kind of plumbing altogether?  
>> (personally I think the o ring will give a better seal and isn't 
>> dependent on cutting the tube cleanly).
>>
>>
>> Thanks, o wisdom of the list!
>>
>
>