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Post by scubalawyer on Sept 25, 2020 19:36:53 GMT -8
Those look like twin 72's. Far to heavy for me these days but we used to get lots of bottom time from them. Good score! I wasn't sure what kind of time to expect since they are 1,800 PSI tanks. At 1800 psi those might be twin 53's. Very similar in physical size to a 72 but obviously lower working pressure.
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Post by james1979 on Sept 26, 2020 3:37:28 GMT -8
I just picked up a set of USD 1800 psi twins that look almost just like rikdog7's.... only with a USD J-manifold and a higher price than he paid. Lucky bum! lol. From what I've seen researching it looks like they are the twin 53's Scubalawyer mentions. Mine are getting separated for the my youngest to use as singles.
Respectfully,
James
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Post by SeaRat on Sept 27, 2020 17:16:07 GMT -8
I just picked up a set of USD 1800 psi twins that look almost just like rikdog7's.... only with a USD J-manifold and a higher price than he paid. Lucky bum! lol. From what I've seen researching it looks like they are the twin 53's Scubalawyer mentions. Mine are getting separated for the my youngest to use as singles. Respectfully, James James, Assuming that the volume is the same as a 72, the ratios would become: 71.2 / 2475 = X / 1800 so, 71.2 / 2475 = 0.03 0.03 x 1800 = 51.78 I'm not too sure about this calculation, but it seems to work out. Anyway, rikdog7, I have that same valve, and it a great valve. I have used it with my single stage, double hose regulators and put a single hose regulator on the other post, which was equipped with both a LP hose for my inflator for the BCD and a pressure gauge/computer. It works really great. I would suggest that you put your efforts into getting this unit going, and leave the other unit for display unless you really want to fiddle with the two plugs on each side and the 1/2 inch valve, sealed with teflon tape, and the valve itself with a teflon washer instead of O-ring to seal against the regulator. Concerning the tank bands, many older Scubapro backpacks (even for single tanks) have two vertical holes that can be drilled out for use with your double tank bands. It would look like mine here: IMG_1630 by John Ratliff, on Flickr IMG_1629 by John Ratliff, on Flickr I still haven't gotten that set wet yet. Oh well, maybe soon. By the way, there are some older jacket-style BCDs that will also handle the two vertical attachments to the tank bands. I repainted the bands silver before putting them on the tanks. John
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Post by rikdog7 on Sept 28, 2020 6:10:47 GMT -8
I just picked up a set of USD 1800 psi twins that look almost just like rikdog7's.... only with a USD J-manifold and a higher price than he paid. Lucky bum! lol. From what I've seen researching it looks like they are the twin 53's Scubalawyer mentions. Mine are getting separated for the my youngest to use as singles. Respectfully, James James, Yes, I couldn't believe it when I walked in and got them at that price. SeaRat, Thank you for the advice, and that is a nice setup. Thank you for sharing the pics so I know what to work towards. I think that is what I am going to do. I may go back to the original guy and buy the whole lot of gear he has so I can acquire the double hose from him. He has at least 4 old AL tanks with vintage valves and several Horse collars and fins, plus regulator sets. If I get it I will do an inventory and post some pics. Some of it might be serviceable. It seems as though I always come up with projects for myself to do... now to make a realistic schedule. Luckily viz increased enough this last week at my local lake that I could actually see my dive buddy over the weekend, and not just their light. That's a bonus. Rick
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Post by SeaRat on Sept 28, 2020 13:26:44 GMT -8
Rick,
I have an extra one of those backpacks, and could send it to you for a nominal price.
Also, I'd stay away from old Aluminum tanks, as they have a sustained load cracking problem in their neck threads. I have several that I have decommissioned, and only one still in use. I use it specifically with my Dacor Nautilus Constant Volume System (CVS), and it is not stored full.
John
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Post by rikdog7 on Sept 28, 2020 19:29:06 GMT -8
Rick, I have an extra one of those backpacks, and could send it to you for a nominal price. Also, I'd stay away from old Aluminum tanks, as they have a sustained load cracking problem in their neck threads. I have several that I have decommissioned, and only one still in use. I use it specifically with my Dacor Nautilus Constant Volume System (CVS), and it is not stored full. John John, Thank you for the offer. I ended up buying all of the old gear from the Green tank guy and it has several backpacks. I will check them first to see if any will work. If none of them will, I will send you a message and see what we can do. Right now I'm digging through all of the gear to see what is salvageable and what needs to go on display in my office. Goal one is to do a build similar to yours. Rick.
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Post by SeaRat on Sept 29, 2020 14:12:41 GMT -8
Rick, I have an extra one of those backpacks, and could send it to you for a nominal price. Also, I'd stay away from old Aluminum tanks, as they have a sustained load cracking problem in their neck threads. I have several that I have decommissioned, and only one still in use. I use it specifically with my Dacor Nautilus Constant Volume System (CVS), and it is not stored full. John John, Thank you for the offer. I ended up buying all of the old gear from the Green tank guy and it has several backpacks. I will check them first to see if any will work. If none of them will, I will send you a message and see what we can do. Right now I'm digging through all of the gear to see what is salvageable and what needs to go on display in my office.k Goal one is to do a build similar to yours. Rick. Looking your BCDs over, it looks like a couple of backpaks may work. You're looking for a backpack with two depressions in solid plastic or aluminum that can be drilled for a single hole, about twelve inches apart. Be very careful not to drill into the air bladder though. Best wishes on your vintage diving adventures. John PS, I do not think you should go for another double hose regulator, at least not just yet. Take your Voit and fix it up, as it is not that difficult. Then use it with your double post manifold on the center post. Then use one of your modern single hose regs on the other post with your LP inflator, SPG and the regulator as an alternative. The Voit double hose will be harder inhalation, but just as easy with exhalation as any double hose regulator. You will find it an interesting contrast to the modern regulators, but you will find one thing none of the others have, and that is extremely quiet breathing. I have a DA Aqualung (Broxton green label), the USD equivalent of your Voit. I like it for very close observation of fish, even with the harder breathing. Remember also that the Cousteau team, and the U.S. Navy, used this regulator for over ten years.
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Post by rikdog7 on Sept 29, 2020 15:55:40 GMT -8
Thanks John, I measured the double band and it is exactly 12 inches. I glanced at the BCD's and it is going to be close. I am going to try to look at it better tomorrow. I agree with the regulator advice and I like a good challenge so I am going to work on the VOIT. And yes I am going to use a newer regulator on the other post until I learn how to dive a double hose. I need to start working on getting the tanks back in service while I am figuring out how to rebuild the old regulators.
Would you use these middle size steel tanks, or swap out for two of my bigger tanks I just got? I think they are 72's from what I can tell. They have 2250 on them and measure 26" tall. Rick
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Post by SeaRat on Sept 29, 2020 16:31:22 GMT -8
Rick,
Unless you plan on deep or long dives, I'd go with the 1800 psi tanks. They will be somewhat lighter and easier to move around.
Don't worry about the disrance between the bands; you can change that to the needs of the backpack/BCD.
John
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Post by rikdog7 on Sept 30, 2020 21:30:30 GMT -8
Rick, Unless you plan on deep or long dives, I'd go with the 1800 psi tanks. They will be somewhat lighter and easier to move around. Don't worry about the disrance between the bands; you can change that to the needs of the backpack/BCD. John John, That sounds like a good plan on which tanks to use. I was able to pull the backpack out of the Dacor and it is going to work perfect. It is molded to weave a full harness through and the indents for bolts have good spacing. Also, my tank bands have a curved section that should sit nicely in the single tank spot on the backpack. I don't have enough time to put it all together until next week, but when I do I will post a picture. I got a lead today on a place that might be able to do my hydro's. I don't mind taking one or two tanks to my LDS, but I have 9 tanks that need done so I can figure out what I am going to do with them. Thanks Rick
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Post by surflung on Oct 1, 2020 8:03:02 GMT -8
The bushings and valves on your original green tanks are a bit different than the usual set up. The hex head on top of the tank looks like a bushing but it's screwed in flush... Where a usual NPT tapered thread bushing would leave a gap for future tightening. So, I'm wondering if that one is maybe a sealed ADAPTOR rather than a tapered thread bushing. Maybe sealed with the old pipe dope method.
Then on top of that you have another more traditional looking tapered thread bushing, but it is smaller than the usual setup. The two angle pieces look like they came from a non-scuba application... Which is entirely possible because the center yoke valve is actually a standard CGA connection even though it is specifically Scuba.
I believe the center yoke valve can be swapped with a more modern USD version that uses an O-Ring. BUT the other pieces may have to be re-used as configured.
Typically these surplus tanks have a large 1" tapered thread. You put a bushing in there that reduces to 1/2" tapered thread. Then this fits the complete USD 1/2" tapered thread double tank manifold. But the flush mounted tank bushing on your tanks will have to be examined to see if they can be done that way or not.
Finally some thoughts on the tanks. Your steel is "3A" as opposed to others with "3AA". I have singles and doubles made from both. Apparently 3AA is preferred but I have had successful Hydrotests done on both. If you can skip past the dive store and go directly to the hydrotesting facility it will be better. The process is called "Cylinder Requalification" and they do it for welding tanks, oxygen tanks, CO2 tanks, propane tanks... etc. These facilities test tanks of all ages and materials. They won't be hung up on ignorance... Such as "these old things will kill you"... That many dive shops might do.
Also, they may be more flexible. For example, we were allowed to use an odd bushing to hydro a steel 72. The hydro facility didn't have a connector that matched the bushing thread. So they used their std 1/2" tapered connector and just connected with the odd bushing on the tank. It passed well within the specs.
Finally, I believe those are 38 cf tanks at 1800 psi. Typically they can be filled 10% over to achieve Twin 42 cf capacity. That's a total of 84 cf. And they are nice and light. They may float even.
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Post by rikdog7 on Oct 2, 2020 5:58:57 GMT -8
Surflung, Thank you for such a detailed comment. That is very useful information. I was curious about the bushings and the thread sizes. I have done some research on the tanks, but your observation and clear explanation helps me understand a little better. I contacted my local fire chief yesterday and he told me where they take their tanks. You have confirmed what I thought about the size of the tanks, and they are very light compared to everything else I have. I made a spreadsheet this week to keep up with all of the different tanks. All of those tank codes, volumes, thread sizes, and dates were swimming around in my head. I will add your information to my list. I am not sure what I will do about the manifold. I don't see this being my primary twinset because I want to use my VOIT on it. I am not sure if VDH would do the Phoenix mod on my model so I would probably assign a MOD in that configuration that I was comfortable with. Thanks a bunch. Rick
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Post by SeaRat on Oct 2, 2020 12:12:55 GMT -8
Surflung, Thank you for such a detailed comment. That is very useful information. I was curious about the bushings and the thread sizes. I have done some research on the tanks, but your observation and clear explanation helps me understand a little better. I contacted my local fire chief yesterday and he told me where they take their tanks. You have confirmed what I thought about the size of the tanks, and they are very light compared to everything else I have. I made a spreadsheet this week to keep up with all of the different tanks. All of those tank codes, volumes, thread sizes, and dates were swimming around in my head. I will add your information to my list. I am not sure what I will do about the manifold. I don't see this being my primary twinset because I want to use my VOIT on it. I am not sumre if VDH would do the Phoenix mod on my model so I would probably assign a MOD in that configuration that I was comfortable with. Thanks a bunch. Rick Rick, The Phoenix mod is not available for your Voit. Yours is a first generation Voit Lung, and the orifice is pointed 180 degrees from the intake horn. It is the same as the DA Aqualung, Broxton green label regulator that I have. I recently found some inhalation/exhalation measurements I took on my regs some years ago, and will dig them out gor my Broxton and post them. John PS, on 3-14-2013 I made measurements on all my regulators at that time for inhalation and exhalation resistence, using a Dyer Mk II, Model 25 Inclined Plane Monometer, calibrated to zero inches of water and balanced to level. Here are the results for my DA Aqualung, Broxton Green Label: Exhalation: breaking, 0.8-1.2 inches of water Hard, 1.8-2.0 inches of water Inhalation: Breaking, 2.5-3.0 inches of water Hard, greater than 3 inches of water As you can see, the exhalation is fine, but inhalation is over what divers nowadays would like. Here are some photos of the DA Aqualung: Broxton Dive 8-10-2015-3 by John Ratliff, on Flickr DA Aqualung-2 by John Ratliff, on Flickr DA Aqualung-1 by John Ratliff, on Flickr Aqualung Regulator-2 by John Ratliff, on Flickr
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Post by rikdog7 on Oct 2, 2020 15:58:54 GMT -8
John, That's what I figured on the Voit, and thank you for those resistance numbers. I have never looked at monometer readings for human regulators before, just motorcycle regulators, a.k.a. the carburetor. Nice looking rig. Now it's time to read a thread about disassembly of my Voit. Rick
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Post by snark3 on Oct 2, 2020 23:06:38 GMT -8
Rick- According to the manufacturer list I have the WK&Co indicates they were made by Walter Kidde, the H in the shield is for Robert W. Hunt, an inspection agency.
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