"O" ring for Sportsways manifold

[14020]

I have a Sportsways Manifold which I use and for the last 20 year I have not had any problems. Recently I had the tanks tested and O2 cleaned. I also had the manifold service and O2 cleaned.

The tanks are fine but the manifold came back with the brown O2 O rings in the manifold and they keep failing.

Does anyone out there know the specs for the O ring which go inside the manifold? They are fitted on the end of the center piece which has the valve.

[SurfLung]

-Is this the manifold you're talking about? If so, I replaced these deformed O-Rings with a proper fitting O-Ring from my divers O-Ring set... Just a regular black one and it has been sealing and holding air fine for 6-8 months.

- Sorry I don't know the size I used... The O-Ring set had several sizes and I just tried different ones to find the right fit.
- From the discussion by VDH members on the original deformed O-Rings, it sounded like the originals were too big and that would not allow the metal on metal contact this valve yoke needs to enclose the O-Ring properly.

[captain]

The O ring needs to be of a size to fit into the elbows so that when the nuts are tightened the O rings are not pinched. Put the O ring on and try to push the center into the elbow, it should slip in until metal to metal contact is made. The ones in the picture were too big in cross section that is why they were mashed. I would say somewhere around a -012. Any size beginning with -1 would be pinched.

[14020]

Yes that is the manifold I am talking about.

You Guys are just amazing!

The information both of you have provided gives me an understanding of how the coupling works and what I need to look for when rebuilding the manifold.

Tom, thanks for an indication of the size "O" ring I should be looking for.

I will also check the metal surfaces to ensure that they are clean and smooth and I will tighten the coupling so that the surfaces are in contact.

It is the people you find on this Forum that set it apart from the others. You Guys are the BEST!

Thanks,

[14020]

I have also been advised that Gorilla Torque will help.

[captain]

I have also been advised that Gorilla Torque will help.

Only on the metal to metal sealing surface manifolds such as US Divers and similar Voits, not on the O ring sealed Sportsways.

[simonbeans]

Ditto to Capt'n.

[14020]

I'm glad that you guys are around and that this forum is here too.

Can someone please explain to me how the US Divers manifold seals without an O ring?

Is the seal simply achieved by Gorilla Torque?

[captain]

All gas welding equipment uses metal to metal sealing connections. The matching smooth surface of the brass ball and socket connection fit together so well and the contact point is so narrow that any gap is smaller than the gas molecule so it can't leak.

Think of the connection as like a wooden icecream cone shaped plug driven into a hole. Only a thin contact line exists where the cone touches the edge of the hole.

You really only need gorilla torque if the surface of the ball and socket becomes scored or scratched, in that case gorilla torque mashes the the brass together and smoothes out the contact point which is very narrow. The contact point gets scored when the ball is allowed to turn in the socket when tightening the nut. You only want the nut to turn.

[14020]

I thought that the entire surface of the the ball and socket had to be in contact. The picture you have pained is clear. I now have a true understanding of how the joint work.

Thank you very much Captain.