Older steel tanks?

[Gerbs]

I occasionally help at the local tank testing place (trading muscle for testing).

The oldest tank tested (passing visual and hydrostatic inspection with flying colours) had a manufacturing date of 1934, complete with swastika.

The main issue with tanks is the varying valve threads. Here in .de we have, amongst others: small diameter conical, large diameter conical, imperial as well as metric M25 or M18. As a rule, anything reasonably new has a metric thread (storage tanks, oxygen cylinders and breathing apparatus being the exceptions). Older threads are not a problem if you keep the original valve. If you want to change (joke to DIN, single to twin regulators, doubling up), you may very well be SOL. The threads I mentioned, you can get valves for.

We found one tank (bought second hand with a single yoke valve) that had a thread where new valves are unavailable (NO SANE PERSON will dive a tank where the valve is held in by less than 2 full threads...). Even though it passed hydro (with only the 2 threads holding!!), we decided to retire the tank. The owner, one of our instructors, donated the tank to make a high volume ashtray for the diving club, which is what we are using it for now. Manufacturing date was sometime in the 70s, but the original valve was unserviceable, so selling it on was contraindicated. At least, it is still in service helping divers put stuff into their lungs...

Germany specific advise unless the same problem exists internationally: If you want to be liked by the people servicing your tank, get tanks with large diameter valve threads. It makes access to the tank for visual inspecting / cleaning / scrubbing easier. Also you can buy any and all valve configurations for M25 to set up your rig to your hearts content... Small Conical is an affliction, not a sensible valve thread on a tank

Gerbs

 

[Gilldiver]

The oldest tank tested (passing visual and hydrostatic inspection with flying colours) had a manufacturing date of 1934, complete with swastika.

I'm surprised that a swastika would be on that early of a tank unless it was put on later in the 30's or 40's. In the US we will see old Linde tanks with the swastika, but in every case the open sides have been boxed out to look like a window pane like below. Some will be a little off so you can see that the swastika was there originaly and the 4 streight lines to box it out added later.

 

[Gerbs]

I'm surprised that a swastika would be on that early of a tank unless it was put on later in the 30's or 40's. In the US we will see old Linde tanks with the swastika, but in every case the open sides have been boxed out to look like a window pane like below. Some will be a little off so you can see that the swastika was there originaly and the 4 streight lines to box it out added later.

I was fairly surprised as well, especially as the swastika is a symbol non-grata in .de (use banned unless for historical research reasons). Possibly even added later on by an overzealous part-time historian with possible dubious political leanings. Can't remember if there was a windowpane on the tank, but there might well have been.

Gerbs