Looking at buying a set of PST HP100’s, need advice

[Kyle0692]

Hi all,

My local dive shop has a couple of used Pressed Steel HP100’s that will be available for $250/piece after they go through VIP/hydro. The tanks are the 3,500 PSI style with 7/8” necks and were made in the 90’s and are hot-dipped galvanized. I am looking at buying these tanks for my first set of doubles to add to my tech kit that I am working on building. My understanding after searching through posts here on the board are that these are quality tanks and they must utilize 300 bar valves.

Doing some searching online for 300 bar valves of the 7/8” neck size is not turning up too much. XS Scuba makes them, but they specifically state that they are for air only. Not sure if the internals of the valves are different than most 300 bar valves that can be o2 cleaned to be utilized with nitrox or what. I will definitely be using nitrox in these tanks more often than not. Anyone have thoughts on valves I could look at buying?

I will also need a manifold/bands. Will any 300 bar manifold work with these tanks with them requiring the 7/8” valves? Not sure if the neck diameter matters here or not, but just want to be sure in case it influences the connection size of the manifold that is required. Can someone confirm the tank diameters are 7.25”?

Thank you!!

Kyle

 

[Jim Lapenta]

Will the nitrox be from banks or partial pressure blending? If the latter then O2 clean is called for. If banked then they don't need to be O2 clean.

 

[Kyle0692]

Jim,

I would like to have the option to fill both ways. My local shop has a membrane system to generate nitrox, however, many south Florida shops utilize partial pressure blending and this is where I dive most often.

Thanks,

Kyle

 

[Jeremy Williams]

To the best of my knowledge there is no longer a manifold being manufactured for tanks with a 7/8 neck. That makes sense in a certain way because those tanks have not been produced in many years. The current market for new 7/8 neck valves is very small.

Those manifolds do pop up here for sale periodically.

 

[runsongas]

XS Scuba Thermo DIN Manifold 7/8-UNF 3500psi

there is an option to get the 7/8 manifold, but it is pricey and usually a special order

standard 7.25 bands work just fine.

 

[Jeremy Williams]

XS Scuba Thermo DIN Manifold 7/8-UNF 3500psi

there is an option to get the 7/8 manifold, but it is pricey and usually a special order

standard 7.25 bands work just fine.

At one point I had one of those on order for about six months. This was a couple of years ago. I cancelled the order because there was no reasonable expectation that it would be possible to fulfill it. YMMV. If you get a brand new Therno from XS I’d love to know.

 

[happy-diver]

I am looking at buying these tanks for my first set of doubles to add to my tech kit that I am working on building.

Dude I feel it, but the best way to set yourself up is patiently.

Doubles already set up from the used market is the only way

Unless the dive shop is able to provide you these tanks set up as doubles it's a bad deal
Even if the dive shop is able to provide you these tanks set up as doubles it's a bad deal

Why is the availability of 7/8 things limited


I woke up early on new years day one day and drove to Sydney to grab these
That's Nick, not hard to remember his name, he wanted 400 for the tanks, a 100 for the H wing

Nick is smiling because I'm funny and also I gave him an extra 100 on top because I'm smiling too

Thanks again Nick, hope you and the family are well

Can you imagine driving through Sydney and over the bridge with virtually no traffic

 

[Kyle0692]

Dude I feel it, but the best way to set yourself up is patiently.

Doubles already set up from the used market is the only way

Unless the dive shop is able to provide you these tanks set up as doubles it's a bad deal
Even if the dive shop is able to provide you these tanks set up as doubles it's a bad deal

Why is the availability of 7/8 things limited


I woke up early on new years day one day and drove to Sydney to grab these
That's Nick, not hard to remember his name, he wanted 400 for the tanks, a 100 for the H wing

View attachment 532660

Nick is smiling because I'm funny and also I gave him an extra 100 on top because I'm smiling too

Thanks again Nick, hope you and the family are well

Can you imagine driving through Sydney and over the bridge with virtually no traffic

Oh, I am patient! I was thinking these may be a good deal until I saw how much a 7/8” manifold was, hah. If they have a manifold to go with them, that may be the way to go. I haven’t committed yet, just said I was interested. I can buy new faber HP100’s for $350 and not have to worry about parts availability. Will keep my eyes open, but is good to know that mainstream 3/4” 300 bar manifolds will not work with these tanks.

Kyle

 

[Scared Silly]

IMHO I would skip 7/8" cylinders because of the limited availability of valves. Personally I would get a pair of LP85 and double those up. Get a good fill at 3100 psi at you have the same amount of gas in cylinders that have a lower dry weight.

 

[2airishuman]

There are manifolds out there but they usually come with cylinders.

I have two Dive Rite-style manifolds in 7/8". One on a set of PST 100s and the other on a set of PST 120s.

They are nearly impossible to purchase by themselves but if you watch long enough you might find someone who had a cylinder fail hydro for some reason who is therefore selling the manifolds.

There are HP galvanized steel PST cylinders with 3/4" necks. I have one of those, too. It's mate suffered an early death because a hydro place needlessly condemned it because some of the galvanizing was flaking off. Choose your hydro place carefully. I like hydro places that are careful and conservative. I don't like hydro places that wreck perfectly good tanks out of ignorance

The Worthington ones are OK too but are IME a few pounds heavier.