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SurfLung
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Sportsways 1/2 vs M18?

Wed Jan 02, 2019 10:42 am

Does the Sportsways 1/2 Straight valve fit M18 composite tanks?
- I was removing valves on several tanks to take to Hydro testing and noticed how similar the threads looked on my Sportsways 1/2" straight thread valves to the threads on my composite fireman's tank. I believe the fireman's tank is M18-1.5 thread but I may be wrong. Anyway, I tried swapping the valves and found the the firemans valve fit my sportsways tank and my Sportsways valve fit my firemans tank. There didn't seem to be any slop. The only difference was the fit of the O-ring. The firemans tank seems to have a thicker O-ring.
Image
- The firemans valve is made of aluminum and the threaded section is longer
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- The valves interchange with no wobble or binding. Just different O-rings.
Image
- Leakage... I tried filling a little air into these the fireman's tank with the SW valve but leaked around the O-ring. Unfortunately I didn't have the right sized O-ring to make it seal.
- Any Thoughts?
SurfLung
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SurfLung
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Re: Sportsways 1/2 vs M18?

Wed Jan 02, 2019 12:11 pm

Okay, Here's a Thought...
- Maybe my firemans tank is not M18? On my last hydro test of the Twin 42 Sportsways set, the first testing facility failed both tanks because of leakage around the O-ring. The second facility I tried, spotted the leak and changed to a better fitting O-ring. The result was the tanks passed by a wide margin.
- I'm thinking both facilities had a common fireman's SCBA threaded adaptor that also fits 1/2 inch straight thread Sportsways Scuba tanks. The only difference was that the Sportsways tank uses a different sized O-ring.
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Re: Sportsways 1/2 vs M18?

Wed Jan 02, 2019 12:44 pm

Those fire industry tank threads aren't metric, and they are a standard size and are an actual match for the Sportsways, as you discovered. I use a Sportsways manifold in a nice set of old steel cylinders that I obtained from a FD that was retiring them. Same place that the 38's of yours with the larger threads came from.
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Re: Sportsways 1/2 vs M18?

Wed Jan 02, 2019 2:11 pm

I agree with Bill about the thread sizes on the SCBA happen to be the same as the old Sportways. I have seen old steel SCBA cylinders repurposed for SCUBA.
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SurfLung
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Re: Sportsways 1/2 vs M18?

Wed Jan 02, 2019 2:32 pm

Ah-HA! Thanks Bill and Luis!
- This assures me that any Hydro Testor that does SCBA tanks should have an adaptor for the Sportsways tanks!
- Also, it means I can try diving a composite cylinder without having to BUY one. The one in the pictures is expired past its 15 year date but I figure it will hold a few hundred psi so I can just see what it dives like. It is SO light in weight, I'll probably need a lot of weightbelt.
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Re: Sportsways 1/2 vs M18?

Wed Jan 02, 2019 3:29 pm

One Thing Leads to Another...
- Okay so the Sportsways valve is same as SCBA .750-16 UNF-2B. Now I see a BUNCH of expired composite fire fighters tanks for sale... Mostly about $50 and discussion forums seem to be made up of Airgun fans buying these up to use with their own compressor. I actually HAVE one of these compressors... It looks like a T-Handled tire pump but it will pump up an airgun to 4500 psi. It would probably take about 3 years to fill a scuba tank (exaggeration). But I think those guys are using that and just going ahead and filling the expired composite cylinders.
- Another thing I found was a place that re-certifies expired composite cylinders for another 15 years. Cost is $300.
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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Re: Sportsways 1/2 vs M18?

Wed Jan 02, 2019 4:22 pm

Hey Eben, It probably has already occurred to you that that floating cylinder will be like your namesake USD floating toy snorkeling device as you bob around in the waves. :lol:
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SurfLung
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Re: Sportsways 1/2 vs M18?

Mon Jan 07, 2019 10:30 am

Actually, I was thinking a set of composite tanks might be made up with the Sportsways 750-16 UNF manifold and they'd be as light as the suspected balsa wood tanks that Mike Nelson man handled so easily on Sea Hunt above water scenes. Even the light weight 1800 psi Twin 38s are much heavier than these composite things. You're right. I'd probably have to wear an enormous amount of weight on my weightbelt to offset the buoyancy. :)

BTW - I'm trying a new Hydrotesting facility. Tomorrow morning Rich and I are driving down to a place called Hydrostat, Inc. in Rice Minnesota. We're brings over 15 tanks and they're giving us wholesale prices of 13.75 for hydro and 3.75 for visual. I talked to a technician there and he was very helpful and informative. For example, they can shot blast tanks inside and out if needed... Also for a cheap price. They even re-condition tanks... Aluminum and Steel. You bring 'em in all beat up and take them home all tested and approved with a new paint job (if you want). We're just going for the Hydrotesting and visuals this time.

BTW-2 I have all of my Twin 38s and Twin 42s disassembled and the tanks all look pristine inside... So the RIX SA3 compressor with condenser towers and Bill's filter array is pumping nice dry air!
SurfLung
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Re: Sportsways 1/2 vs M18?

Mon Jan 07, 2019 11:00 am

The testing costs sound very reasonable. That's about what we used to pay wholesale a few years ago. Now it's about 20 at a place about 35 miles away. Place I used to use is less, but it's 71 miles away through heavy city traffic. Ugh, not worth it.

Glad to hear your tanks are staying dry inside. That's due to your diligence in properly maintaining the filter system. Good job :D !
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SurfLung
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Re: Sportsways 1/2 vs M18?

Wed Jan 09, 2019 3:38 pm

antique diver wrote:
Mon Jan 07, 2019 11:00 am
...Glad to hear your tanks are staying dry inside. That's due to your diligence in properly maintaining the filter system. Good job :D !
I owe it all to you Sensai! :wink:
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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