Purchasing advice for used steel HP tanks

[Seaross]

Do these even have DOT and TC ratings for use in North America?

should they?

 

[2airishuman]

There have been a few twinsets with bands and manifold of used HP100s (fewer 120s) listed in my area.

Typical used prices are $150-$200 per cylinder for HP100s and HP120s in "as found" condition i.e. out of hydro, in uncertain condition, and with a valve that is probably shot. Early PST cylinders with the 7/8" valves are usually worth somewhat less, unless they come with valves with a lot of years left on them, because the cost of replacing the valves is so high. The PST cylinders are usually slightly lighter, the Worthington cylinders don't have the "PST HP hydro problem," I figure the values are about the same. Bands add to the price.

What is the life of a scuba tank to pass hydro? They were born in the early 90s. Any advice as to what to look for or out for?

They will last indefinitely unless they are mistakenly condemned by a hydro shop (which is common), or are corroded as a result of water intrusion into the cylinder. I have galvanized steel cylinders from the 1960s that I still use. For welding and other industrial uses, it is not uncommon to encounter cylinders in active use that were manufactured in the 1920s; these are made to largely the same standards as scuba cylinders but are not galvanized.

Ideally you would pull the valve and inspect the tank, by putting a small flashlight inside. If there is visible pitting or there is rust that is visibly raised above the surface of the wall, the cylinders may fail hydro.

I have noticed some misleading statements such as in hydro and VIP when after looking at some of the pics of them they are not. Some listed for anywhere between $320 to $600. I estimate the VIP, O2 clean, hydro and assembly will be about $125-150 for the set at LDS depending on whether they need tumbling. Any advice or experiences would be appreciated.

The prices, and the services available, vary widely regionally and between shops.

Typically it is no longer necessary to O2 clean primary dive cylinders because partial pressure blending is now rarely used. Tumbling can be expensive, but it is unusual for a tank to truly need it. Usually a whip and bottom brush will clean up any surface corrosion.

 

[-JD-]

Are you saying those HP100s had a brand new hydro and VIP, and yet your LDS "took a peek" anyway and found rust?

Yep.
Used tanks. Hydro and VIP within the prevoius couple of months of my late February purchase so I doubt anybody had taken a dive and flooded them after.
This was NOT just a hint of rust either ...

My LDS is Northeast Scuba Supply, and John has a LOT of -stuff-. I had been waiting for a batch of HP100s from him to be finished recon, but they got sold out between trips to the shop so I was left to look elsewhere ...

 

[rjack321]

should they?

no shop can legally fill them in North America without DOT and/or TC approval so there's that

 

[rvojr]

I had bought these a few months ago but am unable to tell the brand or the thread size. Could you explain how to figure it out?

 

[aviator8]

Those look like pst hp 3500 cylinders with 7/8 neck thread

 

[rvojr]

The valves are a little weird but they work ok. I need to get them VIP'd shortly. Are manifolds for that size difficult to find? I could just change over my 100s to doubles.

 

[aviator8]

Yes that is one disadvantage to the 7/8 size. Manifolds are hard to find.

 

[rvojr]

Are there any special issues with a twinset of HP120 2014 Worthington Steel Cylinders? I think I have deciphered the neck markings correctly.

 

[JohnN]

There have been a few twinsets with bands and manifold of used HP100s (fewer 120s) listed in my area. What is the life of a scuba tank to pass hydro? They were born in the early 90s. Any advice as to what to look for or out for? I have noticed some misleading statements such as in hydro and VIP when after looking at some of the pics of them they are not. Some listed for anywhere between $320 to $600. I estimate the VIP, O2 clean, hydro and assembly will be about $125-150 for the set at LDS depending on whether they need tumbling. Any advice or experiences would be appreciated.

I've only purchased used steel tanks. Make the purchase contingent upon them passing Hydro and you're good-to-go.