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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" in 2018

Mon Aug 06, 2018 2:29 pm

Hey Bill,

Post a pic of you on the bottom of the pool with that contraption of yours. :shock:

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

Mon Aug 06, 2018 7:26 pm

Vancetp wrote:
Sun Aug 05, 2018 8:02 pm
I'd like to hear more about the diaphragm fabrication. That seems to be the major stumbling block.
Phillip, I appreciate your interest and sorry for my delayed response. We have family visiting for several days and it's really been eating up my time, but will probably get back to normal late this week.

Please feel free to email or post specific questions here that you have about the diaphragm. If you haven't read the earlier posts about how it was made check that out too, but I certainly am willing to give you any specific info I haven't covered! :D

I also appreciate your latest posts and your suggestion about using the wagonwheel approach. I am definitely leaning that way for better protection of the valve, and may put it on an elbow from the reg housing to make balancing it with the center of diaphragm user adjustable underwater. A brief pool dive with it on Saturday showed me just how sensitive the positioning of the exhaling outlet is in the efficiency of the regulator. It made me glad that most regs exhaust at about the center of the demand diaphragm. The side outlet makes this thing very sensitive to body position, and I want to devise a way to adjust the positioning underwater to make it more comfortable to dive with . More about that later.

Even if I am delayed in responding, you can be sure that I am reading all the questions and comments that you and others make. I appreciate it! :D
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Re: "Build Your Own Diving Lung" in 2018

Mon Aug 06, 2018 7:41 pm

SurfLung wrote:
Mon Aug 06, 2018 10:46 am
Good Luck!
You Crazy Nut!

- Your rig looks better than the ones in the pictures. Congratulations on all of the work and skill you've put into it. VERY NICE!
[/quote]

Eben, thank you for the good luck wishes. I am going to need that.
Your calling me a Crazy Nut is understandable. I'll take it as a compliment because I like taking on odd challenges. I'm beginning to think I am crazy, especially after a test dive I made in the pool Saturday. It demonstrated to me that this is even more challenging than I first expected. While I did come back alive from 16 minutes in the 8' depths I can now vividly imagine the dangers that an inexperienced diver would face with this regulator. I can't help but wonder if some poor soul may have perished while using this questionable conversion. Still, I have confidence that it can be made usable by an eperienced and comfortable diver.

I will get more info posted when company leaves and I get caught up on real work a little. Thanks again to all of you have taken an interest in this project! :D
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antique diver
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Re: "Build Your Own Diving Lung" in 2018

Tue Aug 07, 2018 10:15 am

ScubaLawyer wrote:
Mon Aug 06, 2018 2:29 pm
Hey Bill,

Post a pic of you on the bottom of the pool with that contraption of yours. :shock:

Mark
I'll do that next time. This first dip was sort of spur of the moment, and I had my hands full with the project regulator and getting a friend re-aquainted with diving since he hadn't been since 1988. Turns out he was more comfortable than I was due to the challenging nature of having to breathe through gurgling water. As I expected there was water leaking around the very outer rim of the demand diaphragm since I hadn't sealed it yet where it ties to body. Also a leak coming into main body from the old duckbill that wasn't sealing well. Finally figured out swimming with right side down put the exhaust downward, which helped drain water during each exhalation. This is all fixable, I think.

Due to the construction of the reg the exhaling outlet port comes right off the common cavity. Incoming air goes into that body and into right hose, and exhaled air through left hose right back into same cavity before exiting at the duckbill.
GurgleHissGurgleBlubHiss. When designing this Aviation Oxygen Diluter they just didn't take into account the problem of introducing water into the breathing box... what short-sighted jokers!
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SurfLung
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Re: "Build Your Own Diving Lung" in 2018

Wed Aug 08, 2018 3:36 pm

- Please excuse the "Crazy Nut" reference... I meant it affectionately. :oops:

- Looking back at the 1953 date of the article, these rigs must have been in use for a few years prior... Maybe even late '40s? And judging from the smiles on the faces in the photographs, and your cave diving story, they must have worked respectably well.

- This brings up something I have often pondered. We are always commenting on how easy breathing this or that regulator is. But I don't remember even thinking about ease of breathing back in the late '60s and early '70s. And likewise, I think the divers who used your "Build Your Own" were probably just happy to be able to breathe under water.
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Vintage Diving Technique are Why I Got Back Into Diving.

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Re: "Build Your Own Diving Lung" in 2018

Wed Aug 08, 2018 7:12 pm

SurfLung wrote:
Wed Aug 08, 2018 3:36 pm
- Please excuse the "Crazy Nut" reference... I meant it affectionately. :oops:

- Looking back at the 1953 date of the article, these rigs must have been in use for a few years prior... Maybe even late '40s? And judging from the smiles on the faces in the photographs, and your cave diving story, they must have worked respectably well.

- This brings up something I have often pondered. We are always commenting on how easy breathing this or that regulator is. But I don't remember even thinking about ease of breathing back in the late '60s and early '70s. And likewise, I think the divers who used your "Build Your Own" were probably just happy to be able to breathe under water.
Well, Eben my friend, you can't hurt my feelings with that fairly accurate assessment of my mental condition :lol: Call me most anything as long as you smile when you say it.

You comment about breathing effort not really being an issue in the earlier years is right on target. Even though I clearly recall my homemade Hookah rig (1957 or 58) providing air at a much lower volume than I would have preferred, it wasn't a big issue. Like you said, I was "just happy to be able to breathe underwater". That rig taught me to stay calm, move slowly and sip air gently.
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Re: "Build Your Own Diving Lung" in 2018

Fri Aug 10, 2018 3:00 pm

Vancetp wrote:
Sun Aug 05, 2018 8:02 pm
I'd like to hear more about the diaphragm fabrication. That seems to be the major stumbling block.
Phillip, I have caught up a little and have time to resume the project. I will be glad to provide more details on the diaphragm, but please let me know some specifics that would be helpful to cover.
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Re: "Build Your Own Diving Lung" in 2018

Fri Aug 10, 2018 3:16 pm

Vancetp wrote:
Mon Aug 06, 2018 2:02 pm
That Nemrod hose loop looks really dangerous. Please save yourself and ship it to me right away so you aren't tempted to use it! I will put it on a Snark III for display purposes only with a little plaque saying you donated it to the piece. :D

A new loop with a mouthpiece made out of a copper tee fitted to garden hose sections is much more appropriate.....if the hoses are held on with rubberbands!
I guess that confirms my guess that was Nemrod. Thanks for the offer to save me from using it.

I do like the thought of the copper tee mouthpiece rig, and will probably try to make some valves to work with that idea. Thank you. The garden hose part may be a little too basic, but that is what I used on my Hookah rig.
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Re: "Build Your Own Diving Lung" in 2018

Fri Aug 10, 2018 3:43 pm

.
.
Thank you Swimjim for offering the idea about securing the diaphragm to the body with an tight oring! :D

This may be the simplest and most effective way to attach it in a manner that is easily removed for adjustments and servicing. I didn't like the thread wrap method that was originally on the unit, and just didn't even think about this. I experimented with different sizes to get a really good snug fit that would not be easily dislodged. I can probably fit the cover piece with a bushing if needed for additional security to hold the oring in place.
17.diaphragm retainer.JPG
Now I can proceed with a silicone coating of that outer edge, then trim off the excess nylon material. I should be able to remove and replace the oring as needed to perform lever height adjustments and other service as needed.
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Re: "Build Your Own Diving Lung" in 2018

Fri Aug 10, 2018 6:16 pm

Sweet. I'm glad that worked out! :D

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Re: "Build Your Own Diving Lung" in 2018

Sat Aug 11, 2018 1:47 am

antique diver wrote:
Fri Aug 10, 2018 3:16 pm
Vancetp wrote:
Mon Aug 06, 2018 2:02 pm
That Nemrod hose loop looks really dangerous. Please save yourself and ship it to me right away so you aren't tempted to use it! I will put it on a Snark III for display purposes only with a little plaque saying you donated it to the piece. :D

A new loop with a mouthpiece made out of a copper tee fitted to garden hose sections is much more appropriate.....if the hoses are held on with rubberbands!
I guess that confirms my guess that was Nemrod. Thanks for the offer to save me from using it.

I do like the thought of the copper tee mouthpiece rig, and will probably try to make some valves to work with that idea. Thank you. The garden hose part may be a little too basic, but that is what I used on my Hookah rig.
I have often looked at 1 1/4" sink drain couplers as a possible mouthpiece base. The threaded ones might make a kind of Hope-Page like rig....

The metal mouthpiece from my alloy DivAir is stamped "Nibco" which I believe is a manufacturer of copper water supply fittings.

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Re: "Build Your Own Diving Lung" in 2018

Mon Aug 13, 2018 12:23 pm

I have revised the air flow path leaving the demand valve. I had previously removed the very small orifice that provided Oxygen from the demand valve. It was there to create a venturi to pull in appropriate amounts of ambient air from the cockpit to mix according to altitude. Now I realize that I was just dumping the incoming air into the whole insides of the system which probably created some amount of turbulence as it bounced around in the maze of stuff before reaching the final outlet to the hose. By fabricating a plastic tube with a 5/16" bore and sealing into the threaded brass receiver fitting with same bore, the air flow path comes straight out of the demand valve to the hose outlet. Straight smooth path may make for easier breathing, I hope.
19. O2 venturi removed.JPG
20. new air tube.JPG
In the second photo you can see the first stage relief valve beside the red dot. It is necessary for relieving over pressure in case of HP seat leak, since the second stage is of "upstage" type.

More explanation of the very interesting first stage operation, along with photos, to be posted soon. Thanks for watching the progress :D
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Re: "Build Your Own Diving Lung" in 2018

Mon Aug 13, 2018 2:49 pm

I am rethinking the wisdom of directing the exhaled air back into the regulator body. It doesn't take a direct path to the exhaling valve outside the reg, but must go through a circular gap between the outside of the white plastic tube and the cast aluminum manifold surrounding it. That increases the exhalation effort some, but even worse, any water getting in the mouthpiece can be introduced all over the inside cavity and not easily make its way out the current exit to the duckbill. See red arrows for directions that exhaled air can take before making its way to the final outlet. Can leave a lot of water sloshing around in the cavity.

Green arrows show the incoming air direct path to hose loop through the casting, plastic tube and brass tube. But water trapped in the cavity can also go around the brass tube and into the inhalation hose.

Now I'm thinking about attaching only the inhalation hose at the breathing air fitting, just as was done on the original configuration. The exhalation hose would be attached with a fitting to the external body, but no exhaled air or water from a flooding of mouthpiece could get into the main body.

I'm open to suggestions.
28.airflow.jpg
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Re: "Build Your Own Diving Lung" in 2018

Tue Aug 14, 2018 12:59 am

Interesting. Of course, the pilot using this diluter didn't (usually) have to contend with water entering the regulator body, so diverting exhaled air outside the air box wasn't necessary, and it's much simpler to send it through the main body. But, I would not want a double hose scuba regulator that could allow the air side of the box to be flooded. On your project, it would be far better to direct the exhaled air to the opposite side of the diaphragm and out as double hosers do. Or devise a good purge system! Having water enter and spurt around the air side just isn't a great idea for a lot of reasons. It seems to me that there's also a chance of too much rebreathing of exhaled air.

The exhaust outlet should be as close to the center of the main diaphragm as possible, but I've seen examples of regulators that don't direct the exhaled air into the can at all, but exhaust through drillings at the base of the horn. I believe the original Cousteau design had the exhaust come right off the mouthpiece? This didn't work well, of course.

But, to have a separate air side and exhaust side you'd have to make a bottom can with enough space to allow for an exhaust mushroom or duckbill (DBE?). The cover of the diluter doesn't look like it could be easily modded to work.

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Re: "Build Your Own Diving Lung" in 2018

Tue Aug 14, 2018 10:46 am

Lucky for the aviators that there is no provision or need for return of exhaled gases and moisture to the regulator, as it is just exhaled from the oral/ nasal mask directly into the cockpit. Diverting it back through the regulator was an early diver-devised flub, and is potentially dangerous. (Ha, the whole idea of diving with a regulator meant for flying seems kind of dangerous).

Water that may have entered from a dropped mouthpiece, hose leaks or other sources is just much too difficult to remove from the convoluted chambers within the regulator body. Also, as Phillip mentioned, there is a lot of dead air space to be re-breathing exhaled gas. I don't know just how much problem that would actually be gas wise, but certainly moisture from exhaled air would build up during the dive, and be hard to fully eliminate. Not impossible, but in my limited experience of 16 minutes I found that it wasted a lot of air.

After my first experience I am now convinced that it will be much safer and more comfortable to dive with by devising an external outlet for the waste gas. I have some ideas that will be both simple and can be facilitated with materials and technology available in the 40's and 50's. I won't be following the inadequate magazine article to the letter, but trying my best to make modifications that someone could have actually devised at that time. And some probably did.

OK, this is a call for ideas, and I like to hear them no matter how far out because it helps to get me thinking outside the can. :D
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