Value question - Used Steel 72's

[Dash]

I was in a shop recently and they had a couple of old steel 72's for $75 each. They both have new hydro and viz inspections. One has an older K-valve and the other an I-Valve, which, being a newb, Ive never seen before.

My wife and I currently use Faber LP95 and MP72 steel tanks, respectively, but I thought I'd like an extra set for those dive club days where we are at a beach for half the day and would like to get in a 2nd dive.

My question is, these tanks were probably manufactured in the '70s, and with the hydro I know I have at least 5 years of service. Is there anything else I should consider, and do you think $75 per tank is a good deal. (I may upgrade that I-Valve though)

Id love to find a used set of HP72/80, but they are rare on the used market and i wont buy new.

thanks

 

[Ann Marie]

I think $75 is a good deal, especially when a new steel 80 runs about $250. I personally would upgrade at least the I-valve. I would also verify that the burst disk on the other valve is multi-directional and that it was changed recently. If not, have the burst disk changed or put a new valve on that one too. At $100 (including the price of a new valve) that is still a good buy.

As a side note, just because there is a hydo stamp for 5 years on the cylinder it doesn't mean that it will last that long. You get some water in it and at the next viz it could be condemned.

 

[Walter]

That is NOT an I valve. It is a K valve. It is the original K valve. Is it a ½ inch thread? If it is, and I suspect it may be, you will not be replacing the valve, nor is there a need to. It's also very likely not from the 1970s. It's more likely a tank from the 50s or early 60s.

 

[Ann Marie]

Dash,

There were valves made that were "superior K" valves that were a yolk style valve that has a knob on top. Some people call these I-valves but the correct name is "superior K valves".

Between the years of 58-62 there was a transition from 1/2" tapered valves to 3/4" o-ring valves. So if indeed it is a 1/2" valve it is pre-1962.

If the valve does have a single port burst disk (recommended) or lead plug (required to change ) may need to be replaced with a multi-directional burst disk.

I have attached a photo of the superior K valve.

If you had a photo or the markings on the cylinder, that would tell us moer

 

[Dash]

Thanks for the info, very interesting. I will have to look at the dates again if I consider buying these.

Walter, you are adamant it isnt a I-valve. Since I am not versed on valve history, what immediately tells you that it isnt an I valve? Curious to learn more about them..

Ann Marie, the picture doesn't look exactly like what I saw, but its hard to tell. The valve on the tank looked taller.

I guess my question now is, how old is too old? Do I care if it is a 1/2-inch thread and I cant replace the valve? Does it matter how old the tank is if it passes it's tests?

Thanks for the history lesson.

 

[Walter]

Walter, you are adamant it isnt a I-valve. Since I am not versed on valve history, what immediately tells you that it isnt an I valve? Curious to learn more about them.

Because there are no I valves. The letters J and K came from the 1953 US Divers (Aqualung) catalog where those were the identifiying letters for ordering purposes. Other items were A - I. The J and K have absolutle nothing to do with their shape. Years later, long after the K (and J) valve had been modified to put the on/off on the side someone started calling old K valves I valves. Y and H valves are named for their shape.

I guess my question now is, how old is too old? Do I care if it is a 1/2-inch thread and I cant replace the valve? Does it matter how old the tank is if it passes it's tests?

As long as they keep passing, I'll keep using them, but there are some misinformed fill stations that won't fill old tanks. That can be a PITA, but it's fairly easy to work around. The oldest tanks I regularly use are from 1955. I might be interested in these if you aren't (depending on condition, age and location).

BTW, Ann Marie is 100% correct about the burst plugs vs burst disks. The plugs can be dangerous.

 

[Dash]

Great education, thanks Walter. Even if I dont buy them, I think Ill go back just to look and see for my own knowledge.

By the way, it was the shop owner who called them I-valves. I dont want to insult the guy, so Ill have to be diplomatic if I ask him about them!

Since you are interested in the tanks, I guess it answers my question about whether the price is okay and the tanks are a good value, although I doubt you would want to pay shipping from California....