USD Tank Help

[luis]

There is a comedian in every crowd...

[simonbeans]

Note: Simonbeans was just trying to save on words, as opposed to me, who writes these lengthy explanations.

And if you think his thread explanations are lengthy, you should hear his phone ones.

Ditto to what Herman said.

[Dave2]

Luis,
That was a perfect explanation. I really appreciate it. I didn't quite know which O-ring we were talking about but it all makes sense now.
Thanks to simonbeans also!

You guys have probably forgotten more than I'll ever know. Hopefully I can make it to a Sand Dog at some point but I'll be overseas for this coming one.


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[simonbeans]

Maybe a picture is worth a thousand words, or Luis' 5,000:

O ring vs. tapered (Both are 1/2"):



And a comparison on the valves commonly used on dive tanks throughout the vintage years:

[luis]

Nice pictures.

[Bryan]

Great post.....great info. Alan I sent you a note about it.

[Dave2]

Excellent pictures. Hopefully I'll pick up the tank today. It should be a 70-72 era along with the DA AM I bought (which should show up at Bryan's shop today or tomorrow).


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[Dave2]

Does anyone know when Sportsways started using 3/4" standard on the LP72's?


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[simonbeans]

Yes, 1966. But they called it a 15/16" O-ring. It has a tank opening of 15/16" like all 3/4" O-ring valves, but for some reason, they preferred to call it their 15/16".

[Dave2]

Thanks. I should have the tank in 2 hours to check. Should be an early 70's tank.


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[Dave2]

So I'm pretty sure I got a 1/2" tank...





Any recommendations?

[crimediver]

Let the air out and take a wrench to it and remove the valve. Don't put the wrench across the face of the valve where the o-ring is as you can mar it and mess it up.
An o-ring sealed 1/2 inch valve should come loose easily although I have dealt with one that I almost never got loose and destroyed the valve in the process.
If the valve is tapered you can see it. It will have teflon tape on the threads as well.

If I am not mistaken, the threads on the straight 1/2" are the same as the old steel SCBA fire department bottles used in Scott Packs back in the 70's. I made a small set of doubles using a pair of SCBA tanks rated at 2016 psi and a Sportsways straight thread 1/2" double manifold. They look like a pair of 38 doubles right out of Sea Hunt.

[simonbeans]

Looks to be a 1/2" O-ring. Use a rubber mallet to whack the turn off knob to loosen the valve. (Lefty-loosey). You shouldn't need a wrench.

[Dave2]

Thanks guys. Took two light whacks with a rubber mallet it it came loose.

Looks like the straight-thread 1/2"



Does anyone make a 1/2" J-valve/J-hook setup for this tank? I'll most likely use a banjo fitting with an SPG but it would be nice to dive the tank both ways if possible.

Thanks again,
Dave

[simonbeans]

Glad the valve removed as expected. However, IF you do need to use a wrench, I have to disagree with Crimediver on its use. I prefer to put one of the jaws across the O-ring face. That way the edges of the O-ring surface won't be rounded off, thus making the mating surface with your reg/O-ring/tank valve out-of proper shape.

As per the Sportsway 1/2" O-ring J valve. I had bunches for a while, but all are in tanks right now.
Check with Rob at Thescubamuseum.com he probably has a few.

Or, you could use this:



Think about that for a while. If you can's get it, check the downloads section and look through an early (1960-64) Sportsways catalog for info.