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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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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Sat Jul 27, 2019 12:51 pm

antique diver wrote:
Sat Jul 27, 2019 9:13 am
Vancetp wrote:
Fri Jul 26, 2019 8:32 pm
I got a great deal on a super clean Bendix oxygen diluter. CRAP!!! I really wasn't going to do this..... Maybe I'll be satisfied with just looking at how it works.
Keep us informed!
It is really doubtful it will go anywhere. I don't like the metal bellows in the first stage, and am concerned about how long it can last w/o fatiguing. If it could be adapted to a rubber diaphragm, that would be better, but that takes the whole thing beyond what would have been done in that era.

Besides, I already have poor breathing, dangerous regulators in my collection! :)

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Sat Jul 27, 2019 1:08 pm

simonbeans wrote:
Sat Jul 27, 2019 12:00 pm
Trying not to be the wet blanket on this thread, but the discussion of DSV on this forum section is beyond the scope of Classic Vintage Diving. The OP discussion on the Bendix is fine, but addition of DSVs (might be the new one for the Argonaut?) is NOT. You could discuss the DSV's use on other forum sections.
I agree... thanks for keeping us on course. :)
The older I get the better I was.

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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Mon Jul 29, 2019 7:35 pm

Got the diluter today. Cool.

I took it apart, and found a pretty decent diaphragm, but probably unusable for diving. Bill has done a pretty amazing analysis of how the thing works, which I'm grateful for, seeing as how the thing is pretty convoluted in some ways.

I can't help but think there's a way around that bellows, which seems to me to be the weakest link. I think a smart feller with a will could find a way to use a rubber diaphragm setup to replace that hot mess...

Speaking of the first stage, and I say this with no knowledge of its potential; is the low output of the regulator to the diver a problem with the second stage? The orifice is small, and I'm wondering if the second stage is throttled by the small opening. As I understand the way this thing works, at this early stage, the 2nd stage output can be modified so it is piped directly into the air horn. Bill modded the complicated stock setup to do this.

But, if you caused the can to be charged by a secondary jet(s) and used a venturi aimed into the air horn, might you pick up more volume from an under-utilized first stage?

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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Mon Jul 29, 2019 7:43 pm

Got the diluter today. Cool.

I took it apart, and found a pretty decent diaphragm, but probably unusable for diving. Bill has done a pretty amazing analysis of how the thing works, which I'm grateful for, seeing as how the thing is pretty convoluted in some ways.

I can't help but think there's a way around that bellows, which seems to me to be the weakest link. I think a smart feller with a will could find a way to use a rubber diaphragm setup to replace that hot mess...

Speaking of the first stage, and I say this with no knowledge of its potential; is the low output of the regulator to the diver a problem with the second stage? The orifice is small, and I'm wondering if the second stage is throttled by the small opening. As I understand the way this thing works, at this early stage, the 2nd stage output can be modified so it is piped directly into the air horn. Bill modded the complicated stock setup to do this.

But, if you used a venturi aimed into the air horn and added secondary jet(s) to charge the can , might you pick up more volume from an under-utilized first stage?

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Tue Jul 30, 2019 8:21 am

I don't think the first stage bellows is really of that much concern for a catastrophic failure. In use it really doesn't flex very much to open the HP seat. As well as that system was designed for its intended use I think the whole thing must be pretty bullet proof for the aviation industry to rely on it. On the other hand I am keeping an open mind on that, so keep me informed on that subject.

As far as danger goes, the whole shebang is not designed to dive with anyway, is inherently dangerous in that use, and warrants a pretty good dose of caution to use underwater. I dive it with the assumption that something in it could fail at any time, causing either a loss of or over-abundance of air flow. I keep hearing the words of John Coffee, and would never subject mine to 3000 psi service (as he did) for fear of a loud noise and disappearing parts. I'm sticking to 1800 psi.

I look forward to hearing more about your project!
The older I get the better I was.

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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Tue Jul 30, 2019 11:56 am

antique diver wrote:
Tue Jul 30, 2019 8:21 am
I don't think the first stage bellows is really of that much concern for a catastrophic failure. In use it really doesn't flex very much to open the HP seat. As well as that system was designed for its intended use I think the whole thing must be pretty bullet proof for the aviation industry to rely on it. On the other hand I am keeping an open mind on that, so keep me informed on that subject.

As far as danger goes, the whole shebang is not designed to dive with anyway, is inherently dangerous in that use, and warrants a pretty good dose of caution to use underwater. I dive it with the assumption that something in it could fail at any time, causing either a loss of or over-abundance of air flow. I keep hearing the words of John Coffee, and would never subject mine to 3000 psi service (as he did) for fear of a loud noise and disappearing parts. I'm sticking to 1800 psi.

I look forward to hearing more about your project!
When electronics burn up, it's called "letting the black smoke out". I wonder what the equivalent saying would be with regulators?

I suppose your assessment of the bellows is correct. However, we don't have a ready supply of replacements.

I've been thinking about your exhaust issue. Why not plumb the duckbill so it crosses the center of the domed cover instead of off to the side?

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Tue Jul 30, 2019 11:11 pm

About the duckbill location.... I placed it to one side for a couple of reasons. Initially it was chosen for the convenience factor. There was an unused opening at that location where I had removed the gas metering and mixing apparatus, I sealed it up internally and used it as a secure mounting device for the copper tee that the duckbill was attached to. Also I reasoned that the exhaust valve in that position would be at virtually the same level as the demand diaphragm, and that would help prevent a free flowing exhaust that could possibly occur with it in a position just above the dome. That would place it almost an inch above the diaphragm in a lower water pressure location when in a swimming position, maybe inviting a free flow.

I had seen photos of earlier conversions that placed it where you mentioned, and also noticed that the commercially sold Seahorse conversion placed it there as well. It just seemed easier to utilize the unused opening to the side as a mounting place instead.

I was pleased with the chosen location to my left of center performance wise. An added unusual bonus was that I could roll to my right side down and decrease the inhalation effort if I needed a little extra flow.

I had intended to test the other duckbill location for a comparison, but since I like the way it was working I just left it alone.
The older I get the better I was.

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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Tue Jul 30, 2019 11:56 pm

I'm all for going with what works!

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Vancetp
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Fri Nov 27, 2020 9:38 pm

Started my own diluter conversion. I wasn't going to do it, but covid social distancing has made me look for more projects. I have a few ideas to make it work better than the PopSci unit. Some are based on Bill's excellent conversion, but I have a couple of new ideas. I'm posting the long version on VSS, but will update here as I go.

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antique diver
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Re: "Build Your Own Diving Lung" in 2018, Revisited in 2021

Sun Aug 22, 2021 2:29 pm

Last week, having the urge for some good old Vintage Diving, I pulled the 1942 model Aviation Oxygen reg/Diving Lung conversion out to see if it still worked well enough for a trip to Wheeler Branch Reservoir (WBR). A quick check on the test stand at 2000 psi, and it passed with its usual one star rating. Cracking effort well below 1", and a strain to pull a heavy breath registering off the 6" scale of my Magnahelic gauge. I know that sounds bad, but it's par for this little jewel, so I decided it was going diving again.

This trip I was to be joined by a long-time old friend from the mid-seventies. Steve came to work with us at the dive shop in 1975 at the age of 15, after being certified by us a while before that. His eagerness to learn everything in the world about diving combined with his quick wit and outgoing personality made him a hit with our clientele. Francie and I quickly counted him as one of our best friends, although we were nearly twice his age.

Somehow we had recently been in touch again, and after reminiscing about the good old days we decided we must recreate some of those fun days of diving. We gathered up some modern stuff (just in case), and loaded my vehicle with a good variety of vintage tanks and regs and got an early start to WBR. On week days you can count on having the best dive sites to yourself, and this Friday was like that.

Steve made a short dip using modern gear since it had been a while, and quickly wanted to shuck that and try the Vintage goodies that were all older than him. So he made dives with the Diving Lung on a single 38 of 1951 vintage, which must have been his first dive without a pressure gauge or BC. He wondered about the subject of determining the remaining air supply, and I reassured him that the Lung would let him know with a noticeable increase in inhalation effort. We did use vintage simple inflatable vests from the 60's, but left them completely empty and adjusted weights for neutral buoyancy. I used a little 27' tank and a 1957 Aquamatic single hose (Aqualungs first single hose reg). Great dive even though the visibility was only about 8'.

Next dive he elected to use my twin 27's that are mounted valves-down, and again no pressure gauge since we can pretty well tell remaining air on those by using right side only until breathing resistance increases. Then, leaving the right side open, "decanting" the left tank into the right until equalized. We started with 2000 psi in the set, and when equalized in the above manner the diver knows he now has at least 1000 in the set. Can then shut off the left valve and repeat the whole process, later ending up with 500 psi in the set. Easy going with no gauge. Steve chose my nice little Divair for the next dive, and for some reason he liked the old Diving Lung better! I think maybe it made him feel like old Jacque. I went with the Diving Lung and used up the remaining air in the 38, staying shallow, and returning with no remaining pressure upon reaching our entry point. My kind of dive... we both came back alive. 8)

So we had a great day of diving and have set another dive for next week with another box of vintage regs and accessories.

I took a few photos in the not-so-clear water, and Steve posted a few along with his comments: Please watch https://www.youtube.com/watch?v=IDt-LU5yg2s
The older I get the better I was.

swimjim
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Sun Aug 22, 2021 3:07 pm

It looks like a good time was had by all! Neat to see the diving lung in the water!

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Sun Aug 22, 2021 5:24 pm

swimjim wrote:
Sun Aug 22, 2021 3:07 pm
It looks like a good time was had by all! Neat to see the diving lung in the water!
We had a great time, and I think Steve has caught the Vintage Bug. It's great to finally have another enthusiast nearby to share some Vintage Dives with. We will be going again soon, and I'll bet he will do a double back flip when he gets to dive with the Spaco. It breathes way better than the Bendix.
The older I get the better I was.

swimjim
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Sun Aug 22, 2021 5:36 pm

That sounds great Bill. I'd like to try that Spaco myself! I always wondered what they were really like. I'm recovering from the first of two total hips and I'll be in dry dock until Spring. So any diving content is really appreciated!! Take care.

Jim

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simonbeans
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Sun Aug 22, 2021 9:26 pm

Great job!! Love the story and photos. Thanks.
Check out my website: www.vintagescubastuff.com

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antique diver
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Re: "Build Your Own Diving Lung", Revisited in 2018 & 2019

Mon Aug 23, 2021 7:56 am

swimjim wrote:
Sun Aug 22, 2021 5:36 pm
That sounds great Bill. I'd like to try that Spaco myself! I always wondered what they were really like. I'm recovering from the first of two total hips and I'll be in dry dock until Spring. So any diving content is really appreciated!! Take care.

Jim
Hey Jim, Francie and I are wishing a speedy recovery for you. Stay off the ice skates this winter and stick with the therapy.
If you find yourself in Texas next summer I'll take you diving with the Spaco.
The older I get the better I was.

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