My 38 dilemma

[ScubaLawyer]

I've been trying to assemble a set of roundy-bottom twin 38's for a while now. I picked up a set for $20 at a garage sale but one of the tanks failed hydro (they only have a born date of 1941. ). I have a mint NIB USD tapered thread dual manifold and new reducer bushings from McMaster-Carr.

I can either try and find a matching tank to complete the set (my preference) or find a single tapered valve to make a single 38 test bench air supply tank or ......? Not sure what I want to do but I figured if I threw my predicament out into the universe some alien lifeform would respond. Mark

[SurfLung]

I had the same dilemma a couple years ago. Then when I looked to find another 38 to complete my set, Antique Diver offered me a closely matched set of round bottom 38s. So, I got my 38s but still had the single. Happily, I made a single tank out of it and have found it to be one of my most fun combinations for lake diving in the Summer. It is SO lightweight. I put it on with just a swimsuit, mask, fins, and weight belt. Diving 15-25 feet it lasts 30-40 minutes. I know you can dive in the ocean right in front of your house... Try a single 38 and see if you like it!

[ScubaLawyer]

I had the same dilemma a couple years ago. Then when I looked to find another 38 to complete my set, Antique Diver offered me a closely matched set of round bottom 38s. So, I got my 38s but still had the single. Happily, I made a single tank out of it and have found it to be one of my most fun combinations for lake diving in the Summer. It is SO lightweight. I put it on with just a swimsuit, mask, fins, and weight belt. Diving 15-25 feet it lasts 30-40 minutes. I know you can dive in the ocean right in front of your house... Try a single 38 and see if you like it!

Hi Eb,

I agree that it would be a fun small tank, but my ocean requires a full wetsuit so by the time I get all suited up I want to have a larger tank(s) on to have a real dive. I'm not the guy who uses the "skin" in skin diver. Maybe if I had a pool it would be different for me. Even if I set it up as a test bench tank I still have to incur the the expense of finding and acquiring a single 1/2" NPT valve. Think I'm gonna keep a lookout for a matching tank. Appreciate the suggestion though.

Mark

[couv]

Back in the summer, someone on SB had this offered up. I don't know if she was selling or giving away.
https://www.scubaboard.com/community/th ... ks.598542/

[ScubaLawyer]

Hello all, I am still looking for a mate to this roundy-bottom 38. Near as I can tell the tank is 18" tall (to base of neck), and the neck is about .75" high. It has 1" opening. This one is a USN, born date 1941.

I have a NIB ½" USD dual manifold and new bushings for putting together the set, just can’t find the other tank (the original mate failed hydro under even the most non-conservative standards ).

I sent a message on the SB post (see above) but no response.

Any new leads would be appreciated.

Mark

[antique diver]

Mark, I almost hate to show you this photo... but I'll do it anyway.



I wish that I still had one of these to send your way, but I will keep my eyes open for one.

Eben is right about diving with a single 38, but that doesn't really work well for your use. Francie's first Scuba tank (1967) was an 1800 psi 38.
The ugly black 38 on top row is now in use with my Bendix Aviation conversion. The one to left is now in service as our shared 38. Ain't it purty?

[ScubaLawyer]

Thanks Bill. I did get a line on a possible 38 tank today. I will post if it works out. M

[BigSwell]

Mark, not sure if these will help but El Cajon is just east of downtown San Diego, 20 mins or so.

-Kevin

https://www.ebay.com/itm/195311314033?h ... R7KNjtDbYA

[ScubaLawyer]

Thanks Kevin, I'll check it out!

[couv]

Mark,

I cannot help you with the tank; but if you're going to bid on something like that on "the bay" I suggest using Auction Sniper (or a similar site) rather than getting into an open bidding war.
https://auctionsniper.com/

Good luck and keep us posted!

Robert

[ScubaLawyer]

UPDATE!

Search currently over for the present. Picked up a set of 38's that look pretty good outside. According to the guy I got them from they were last hydroed and filled in 1980 (42 years ago) and never dove. They still have 1800 psi in them. I checked and oxygen content is at 21% so I'm hoping that means no internal rust. I'll know more when I drain them and pull the valve and bushings out. One has a born date of 1951 and the other 1952. Both are Walter Kiddie tanks. Fingers crossed on hydro.

The manifold is an original Voit with no reserve. I'll probably replace it with a USD J-Manifold I have.

[luis]

With 21% if it has any rust it should be light.

How do they sound when you hit them with any type of metal object, a hammer will do. That is called a hammer test and it should be done on steel cylinders before filling. Just a light tap. A steel cylinder should sound clear as a bell. Any substantial rust will make a cylinder sound dull.

If they sound clear as a bell and with 21%, you should go dive them before you empty them. The 1980 air is much better air than you will find now-a-days. That is unless it was filled with a poorly maintained gasoline compressor or something like that, but that is unlikely.

I would dive them.


BTW, You should replace that burst or at least removed them (if you are not going to use the valve). Those lead plugs just scare the heck of me. I have seen of them go. They can do some damage, like a bullet.


Good luck.

[antique diver]

With 21% if it has any rust it should be light.

How do they sound when you hit them with any type of metal object, a hammer will do. That is called a hammer test and it should be done on steel cylinders before filling. Just a light tap. A steel cylinder should sound clear as a bell. Any substantial rust will make a cylinder sound dull.

If they sound clear as a bell and with 21%, you should go dive them before you empty them. The 1980 air is much better air than you will find now-a-days. That is unless it was filled with a poorly maintained gasoline compressor or something like that, but that is unlikely.

I would dive them.


BTW, You should replace that burst or at least removed them (if you are not going to use the valve). Those lead plugs just scare the heck of me. I have seen of them go. They can do some damage, like a bullet.


Good luck.

If you are testing for a clear ring tone I think it is best done with the bands off to get a true idea of condition. They can damper the tone. Of course that would be best done with empty tanks to eliminate danger of stressing the manifold. Attempting this with full pressure will require a lot of caution and stabilizing the tank positions where that couldn't vary from the banded positioning.

Luis, your thoughts on this subject?

[ScubaLawyer]

Bill, are you trying to tell me that I shouldn't have gone out to the garage and whacked the 70-year old cylinders a bunch of times real hard with a big ol' hammer? Now I suppose you're going to tell me I shouldn't have tied a rope to the manifold and dragged the tanks behind the pickup listening for clear bell sounds when i struck the speed bumps.

[antique diver]

Bill, are you trying to tell me that I shouldn't have gone out to the garage and whacked the 70-year old cylinders a bunch of times real hard with a big ol' hammer? Now I suppose you're going to tell me I shouldn't have tied a rope to the manifold and dragged the tanks behind the pickup listening for clear bell sounds when i struck the speed bumps.

Wow... you're almost as hard on your gear as I am.