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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
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ScubaLawyer
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Re: "Build Your Own Diving Lung", Revisited in 2018

Sun Oct 14, 2018 10:02 pm

antique diver wrote:
Sun Oct 14, 2018 7:42 pm
Who knows what creatures lurk there?  After all, this rocky valley is world famous for it's abundant variety of dinosaur footprints and fossils.  Maybe a Loch Glen Rose monster still prowls under the ancient waters. :shock:


Bill, watch out for marauding plesiosaurs. :shock: :D
cretaceous_predators.jpg
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"The diver who collects specimens of underwater life has fun and becomes a keen underwater observer. .. seek slow-moving or attached organisms such as corals, starfish, or shelled creatures." (Golden Guide to Scuba Diving, 1968) :D

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Sun Oct 14, 2018 10:45 pm

ScubaLawyer wrote:
Sun Oct 14, 2018 10:02 pm
antique diver wrote:
Sun Oct 14, 2018 7:42 pm
Who knows what creatures lurk there?  After all, this rocky valley is world famous for it's abundant variety of dinosaur footprints and fossils.  Maybe a Loch Glen Rose monster still prowls under the ancient waters. :shock:


Bill, watch out for marauding plesiosaurs. :shock: :D

cretaceous_predators.jpg
YES! Those are exactly what I was concerned about while fumbling around in the cold dark depths. :shock:
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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Mon Oct 15, 2018 12:24 am

I had a great day with the "Diving Lung", and it performed as expected... well enough to be enjoyable, but with some limitations as noted below. :D

The Good News: :D
When diving at a leisurely pace and gently sipping air the converted Bendix delivered dry air easily and smoothly down to 20-25' range. Felt like any number of other double hose regulators I have. A little more effort was noticed when descending beyond 25', and on down to maximum depth of 41'. That was as expected, and some of that could have been from an increase in my breathing rate after passing through the really sharp thermocline at 25' and into practically zero vis by 40'. I was wearing my Hydroglove drysuit, but no hood, and temp had dropped from about 72 at the surface to about 55 at 40'. Rolling onto my right side, inhalation got a nice little boost from the exhaling valve then being a little shallower than the demand diaphragm. No problem encountered due to that. Overall pleasant to dive with as long as I did my usual easy swimming and air sipping.

Upon return home I opened up the regulator case and found the insides had remained even drier than expected due to modifications made after first pool test that was so wet.

The Not-so-good News, but as expected:
When breathing heavily there was a disconcerting increase in inhalation effort, even in shallow water. This issue readily showed up even on my test bench, where the cracking effort began at -0.6 inches of water, and could be made to go over -6.0 (off-scale on my Magnahelic) with a heavy demand. In my opinion it was restricted enough to cause a very dangerous shortage of air to a diver who has gotten into an overexertion or panicky condition. Of course this was even more pronounced at greater depths as the air density increased. Remember, this regulator was designed for exactly the opposite, as the breathing gasses decrease in density with altitude. I can see how someone inexperienced could really get in trouble diving with one of these devices during greater exertion or depth of dive.

This issue was expected, and one reason I lugged along a pony bottle. Did not detract from the pleasure of the dive since I was never actually required to overbreathe to the point of discomfort.


Easy entry into calm water, with some vegetation to go around or through in the background. 72-73 degree water with visibility of 10 to 12' above 25' depth.
58.BT entry.JPG
59.bt near surface.JPG
60.return.JPG

Came back alive and unhurt, so I call it a success.
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Re: "Build Your Own Diving Lung", Revisited in 2018

Mon Oct 15, 2018 5:31 pm

Well, I would say that the project was a success. I could see divers back in a day using something that performed like this. If you consider this was from the day of the Broxton green label regs. They were probably only a little better then the diluter. I think that was pre "Over pressue" and about the same time the early DivAirs came out. IMHO they were the first regs that really performed. The two stage regs really didn't perform until the DAAM came out in '58.
So, great work Bill! A job well done!

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Re: "Build Your Own Diving Lung", Revisited in 2018

Mon Oct 15, 2018 6:13 pm

swimjim wrote:
Mon Oct 15, 2018 5:31 pm
Well, I would say that the project was a success. I could see divers back in a day using something that performed like this. If you consider this was from the day of the Broxton green label regs. They were probably only a little better then the diluter. I think that was pre "Over pressue" and about the same time the early DivAirs came out. IMHO they were the first regs that really performed. The two stage regs really didn't perform until the DAAM came out in '58.
So, great work Bill! A job well done!
Thanks Swimjim!

I feel pretty good about it, and had a lot of fun. And I do consider it successful, at least within the parameters of what I originally expected from the questionable conversion to start with. But I can't help but think there is some way I can further improve the diluter for underwater use. It breathes so easily and smoothly at low volumes that I just can't give up on it yet. I fully intend to keep searching for a better resolution to the volume deficiency issue, and already have some ideas to try out.

I must add a comment here about the Popular Science article on making the conversion. It is downright incomplete, inaccurate and dangerous as written.

So this story is not over yet! :roll:
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Re: "Build Your Own Diving Lung", Revisited in 2018

Wed Oct 17, 2018 11:37 am

I got a kick out of your critical review of the Popular Science Article. Those apparently were the days when a magazine could publish a How-To article with little or no likelihood of getting sued... The article was probably a best effort by the author in spite of its shortcomings. And the people who read it and attempted the project probably took it for what it was... Not a perfect solution but "project".

Thanks for posting all of the photos and descriptions, Bill. This has to be one of the best threads ever on the VDH Forum! :)
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The Freedom and Simplicity of Vintage Equipment and
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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Wed Oct 17, 2018 12:14 pm

SurfLung wrote:
Wed Oct 17, 2018 11:37 am
I got a kick out of your critical review of the Popular Science Article. Those apparently were the days when a magazine could publish a How-To article with little or no likelihood of getting sued... The article was probably a best effort by the author in spite of its shortcomings. And the people who read it and attempted the project probably took it for what it was... Not a perfect solution but "project".

Thanks for posting all of the photos and descriptions, Bill. This has to be one of the best threads ever on the VDH Forum! :)
Hey Eben,
As always, I greatly appreciate your feedback and kind words :D . This has been a very challenging and yet satisfying project. I have enjoyed it greatly, and actually just can't quite let it go yet. I still want to improve the volume of airflow, and have some ideas to try. First I need to get caught up on a few other things, but there will likely be more to this story before long.
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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018

Wed Oct 17, 2018 2:08 pm

This has truly been a fun and interesting thread! You are doing an amazing job on the conversion, and I am very happy to hear you are not discouraged by the limitations of the original equipment. The performance of your rig appears to be adequate at moderate depths and easy exertion levels. Keep updating us on your progress and thinking!
Phil

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Re: "Build Your Own Diving Lung", Revisited in 2018

Wed Oct 17, 2018 2:26 pm

Vancetp wrote:
Wed Oct 17, 2018 2:08 pm
This has truly been a fun and interesting thread! You are doing an amazing job on the conversion, and I am very happy to hear you are not discouraged by the limitations of the original equipment. The performance of your rig appears to be adequate at moderate depths and easy exertion levels. Keep updating us on your progress and thinking!
Phil
Hi Phil. Your support, comments and interest is always appreciated, and that is what makes this fun for me! :D

I originally thought that I would just throw something together like in the magazine that might "sort of" work underwater, then I'd park it in a corner to display as one of the failures of the DIY diving lung era. Well, I got excited by all the interest it generated and by my love of mechanical challenges and of being underwater in general. I never envisioned it going this far, but sure glad of it. It has turned into a machine that, even with its current limitations, has been a joy to dive with. Even if I can't improve it further I'll be happy with it, and will continue to do some easy diving with it.
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Re: "Build Your Own Diving Lung", Revisited in 2018

Fri Oct 19, 2018 10:15 pm

I forgot to add this shot of returning to the dock after the test dives, but I do remember exactly how I was feeling. Pretty exuberant.

A slight variation of a phrase from a Willie Nelson song kept running repeatedly through my head (really)....
"I [came up] not dead again today!"

61b.dock.JPG
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Re: "Build Your Own Diving Lung", Revisited in 2018

Wed Oct 24, 2018 9:54 am

I took the back cover off hoping to increase the IP, but even after drilling out the staked dimple a little on the adjustment screw I was unable to turn it with reasonable force. I didn't want to break something and totally wreck this thing, so decided to open the first stage up from this end by removing the four screws.
62.reg dry.JPG


The first stage works came out in one assembly leaving this cavity and exposing the HP poppet, circled in red. Pressure relief valve seat is circled in purple. Poppet has an adjustable screw that if screwed in some may allow it to open more to allow increased air flow???
Trouble with that is, after loosening the jam nut it still didn't want to screw in any. The poppet material seems a little delicate to be forcing too much, so I think I'll leave that alone for now.
64.first st body.JPG



Turning attention now to the bellows assembly, which seems to do basically the same job that the spring and diaphragm does in diving regs. The threaded shaft in the red square operates an L-shaped lever that closes the downstream HP poppet with the end at arrow, so it seems like backing that shaft out a little might let the IP come up a little and/or let the poppet open a little further from the very small volcano orifice. I backed it out one turn, but didn't seem to make much if any difference on the bench. May try another turn later after I give this a dive.
63.first stage bellows.JPG


I have this thought that the bellows capsule may work counter to what is desirable for diving. :| Still trying to wrap my mind around this, but as flying altitude increases the bellows expands at lower ambient pressure, allowing the poppet to open more to allow increased Oxygen volume in the breathing mix. When diving, the ambient pressure increases, collapsing the bellows more and more. That pushes the L-shaped lever into the poppet screw, decreasing the poppet opening the deeper you go!

I welcome any thoughts on this subject.
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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018

Thu Oct 25, 2018 9:36 pm

That bellows appears to be the weak link... And the aluminum. If your rig is diveable, and is relatively safe at moderate depth, your experiment is a success! It doesn't have to be excellent at 180 ft! Nicely done!

This is a snapshot of what the first scuba divers had to do to experience survival underwater! I often hear the oldtimers say, "We didn't care if breathing was hard. We were breathing underwater! Who ever did that before?"

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Thu Oct 25, 2018 11:30 pm

Vancetp wrote:
Thu Oct 25, 2018 9:36 pm
That bellows appears to be the weak link... And the aluminum. If your rig is diveable, and is relatively safe at moderate depth, your experiment is a success! It doesn't have to be excellent at 180 ft! Nicely done!

This is a snapshot of what the first scuba divers had to do to experience survival underwater! I often hear the oldtimers say, "We didn't care if breathing was hard. We were breathing underwater! Who ever did that before?"
Well said Phillip! Thanks for the reminder that It is what it is, and allows me to dive comfortably in shallow water while imagining the thrill the early divers experienced.

That's really all I was hoping to attain anyway. No point in beating my head against the fire coral trying to make it a great performer in deep water. I've got breathing machines that will take me safely to greater depths, so this Lung doesn't have to do that to make me happy with it.

As for the aluminum, I'll likely confine my dives with it to fresh water and carefully dry out the internals after use. That's pretty easy to do with the bypass valve that I can open slightly and let dry air flow throughout the body. If I ever do get in sea water I'll open it up promptly afterward for a good fresh water clean up and drying. The brass and copper doesn't play nice with the aluminum in a salty electrolyte.
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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018

Wed Oct 31, 2018 12:31 am

In the early 1950's materials for the construction of the Diving Lung could be found at specialty stores such as Palley Suplly Co., located at 2263 E. Vernon Ave, Los Angeles, Calif. This store marketed diving equipment and supplied the Aviation Oxygen Diluter AN 6004-1 for the construction of the equipment described in the July, 1953 Popular Science Magazine. A new surplus one was available for only $19.95. Should have included some life insurance to go with it.
65.Palleys adv.jpg
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Re: "Build Your Own Diving Lung", Revisited in 2018

Tue Dec 11, 2018 11:12 am

I was looking at a copy of the 1953 Aqualung catalog this morning, and running the prices of gear with an online inflation calculator. It may give some insight into why DIY equipment was still somewhat popular even when the actual Aqualung product was available.

The only Aqualung regulator available (now referred to as the "Broxton") had a list price of $75 in 1953. That is the equivalent to $710 in today's dollars. That would buy a much nicer high performance regulator today. A complete rig, consisting of a 70' tank, reg, and simple harness was shown for $150, the equivalent of $1420 in current dollars. While not that far off in terms of real cost of new equipment between then and now, a DIY rig could be built from military surplus parts for a fraction of the cost by someone handy with tools.... although at much greater risk to the diver's longevity.
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