- I have three such "Bushing" tanks that I use regularly and four more I am restoring to make Twin 50s and Twin 38s. The ones that were already converted to scuba valves, I simply cleaned up the original bushing and re-installed it and the valve. I have a surplus "Shatterproof" USN oxygen tank I converted to Scuba... That one I ordered a new stainless high pressure bushing from that supply house that was referenced here on VDH.
- The only real drawback to the bushing tanks is that there's a lot of Teflon taped, tapered threads to have to disassemble and re-assemble every year if you intend to comply with visual inspections every year... Compound this pain in the neck when disassembling twin tanks. The hydro test on the other hand is only every 5 years.
- In the beginning, I avoided the expected hassle of dive shop scrutiny by simply cascade filling these tanks with a tank balancing hose. But with a fresh visual sticker on a twin 38 set, I have received fills from a dive shop a couple of times and was never denied.
- But cascade filling these makes a lot of sense ANYWAY:
First, because they are low pressure 1800 psi and they are valuable antiques that you don't want some dive shop to fill them up to 2500 or 3000 psi out of ignorance.
Second, because their low pressure makes cascade filling from modern 3000+ psi tanks very practical. It's essentially what the dive shop does when filling tanks from their storage bank.
- I dove the exact same set of Bushing Twin 38 Tanks for 9 dives at the Sea Hunt Forever event and simply refilled them from 5 other single tanks. Very slick!