Vintage steel 72 rescue center.

[Eric Sedletzky]

Here is the best use I have found for cylinder that doesn't pass hydro:

That's a great idea. I would take it a step further and have the inlet and outlet at the top, then I would have a water drain valve on the bottom. Large steel cylinders will condense a lot of water as a holding tank. We used to mount a large pipe on the wall vertically with the inlet and outlet at the top and a drain at the bottom. We used this air for the paint booth.

 

[Akimbo]

That's a great idea. I would take it a step further and have the inlet and outlet at the top, then I would have a water drain valve on the bottom. Large steel cylinders will condense a lot of water as a holding tank. We used to mount a large pipe on the wall vertically with the inlet and outlet at the top and a drain at the bottom. We used this air for the paint booth.

Yeah, just screw a "T" or cross into the bottom port. I was surprised that such a small volume tank near the end of the LP air run made such a noticeable difference. BTW, have you tried running PEX for shop air yet? Works great.

Speaking of shop air, does everyone know the hazards of using PVC pipe for LP air distribution?

WoodCentral's BP Archives: Shop Air Piping

Basically, when PVC fails it shatters creating tiny shrapnel — think of an exploding cactus. Metal pipe and PEX tubing splits on failure. You don't have the problem with PVC and water because the pressure drops almost instantaneously on failure.

 

[captain]

This is going back a long time, but as I recall the "+" signifies it is ok to have a 10% overfill in the first five years of the tank. It used to be hard to find a good, cool 2500 psi fill. Eventually it became fairly common place. Don't recall many shops refusing to provide 2500 psi fills in 2250 psi cylinders even after five years however.

In almost forty years, I've seen or heard about quite a number burst steel tanks. Fortunately, never first person however. Why did they fail? The reasons varied. How many fail per year, perhaps not that many. Aluminum tanks may be more prone to failure as others have said. It is personal choice but I would prefer to use newer pressure cylinders myself.

This is a forum for vintage diving, correct? Back in the day in the early 1970's, deep air bounce dives weren't that uncommon around SE Florida and in parts of the Caribbean. Accidents during them weren't that uncommon either. Fortunately, survived my deep, ill advised bounce dives before I turned 20, all on tables and air. Used O2 on rare occasion during shallow deco stops. Grew up some, got smarter and moved on after that, largely intact fortunately. Have a bit of old gear, may get rid of it one of these days. In no particular hurry at this point however.

As long as the cylinder meets the requirement to be + rated at the time the hydro test is done the + can be issued through out the life of the tank.

It seems there is more mis-information and illogical ideas about tanks than any other piece of diving equipment.

 

[Scared Silly]

I have one tank that is current but I'm not sure if the VE is required along with the Hydro test, or annually with the VIP. At $10 per VE test, in addition to $15 or so for a VIP, they may not be worth keeping.

Since 2007 the visual eddy has been required for cylinders made from 6351 at the time of hydro. The cylinder must be marked with a "VE" after the hydro date.

Cylinders in current hydro are not required to have a visual eddy until the next hydro - however IMHO it would be prudent to have one done before hand.

What a dive shop may require is another topic. Before the VE at hydro, Luxfer recommended it every 2.5 years. Most dive shops did it as part of the yearly visual inspection.

Can some tell me what the "+" on the 72s means? I realize it means that it can be filled an additional 10% but does it need a new "+" with every hydro test, or is that "+" good for it's life?

"+" calculation at the time of each hydro to maintain the 10% over fill.

 

[rx7diver]

ZKY, PM sent.

 

[RickI]

No, I was never present when one of these tanks exploded, blasting through water tanks, walls, etc.. Happy to have missed out on that experience too. Used to fill tanks while working in a dive shop in Ft. Lauderdale over several summers as a teen in the early 1970's. So, the opportunity was there but we were pretty careful even then. It helped when we started doing VIPs. Lots of interesting tank issues with pitting, compromised internal coatings, wet fills from some other shops, boat compressors and in the islands, exterior corrosion below boots, etc.. The amount of water in some of those tanks was impressive. There were quite a few upset customers over refusal to fill questionable tanks, VIP and certification requirements in the early days. Even broke up a few fights over this stuff.

I have seen lots of the burst tanks however over the years. Plenty on here must have, at least in Florida. They were the strange trophies duckbill was talking about sitting by the air station or newspaper clippings of past accidents in some shops. Storing tanks on their sides, empty, wet fills, poor exterior coatings with corrosion below the boot line, interior coating problems, overpressure fills, lots of causes and some spectacular high pressure vessel failures. With proper testing, VIPs, filling procedures, tank care and no more "operator error" such accidents might become a thing of the past. Still hear about the odd failure though.

So I guess you never really saw any steel tanks "ripped open", right? You're just saying they're dangerous based on hearsay and rumors?

 

[rx7diver]

Mattboy, PM sent.

 

[avidhunter]

I have a steel 72 that has not been used since the 70's, I'll have to go take a closer look and maybe reconsider it.

 

[j yaeger]

if its been closed w/ air-should be ok
vip it and make the call whether to send it out for hydro
great tanks!
have fun
yaeg

 

[ksocall]

I have 2 old STEEL tanks that didn't pass hydro and are now scrap. What can be done with them now? I also have an old Steel that DID pass hydro/visual (but not yet filled), but no one can find me a new value. It has the old 1/2 pipe screw type J valve. Any suggestions?

I also picked up 4 other old tanks from an out of biz scuba shop owner - 3 alum 80's and 1 steel 80 that all did pass hydro/visuals and are now filled....and got new valves for them. I'm hoping maybe for some suggestions on how to go about pricing them for sale? I've seen such a huge range on tank prices....these are 20-30yrs old at least.