High Pressure vs. Low Pressure Steel?

[limeyx]

I have 2 worthington x7-hp 100. They are shorter than 80's and hold more air. The one problem is I usually don't get a full fill when it's cooled, but at 3000 psi I still have about 87 cf. The next tanks I get will probably be low pressure because it is easy to get a fill and they can be overfilled a little.

But the LP tanks would be bigger -- right? So say you get an X7-100. That's the same form factor (give or take) as the LP-80
and LP-95 is generally same form factor as X8-119 or E8-119

So yes you can get a "better" fill -- but you are carrying more tank around.
so getting say an LP-100 and getting a "full" fill is kind of the same as saying you got an HP-119 or 130 and got a cruddy fill

Generally I guess the HP tanks are more $ for the cft, but I tend to like them as I can sometimes get 3400 or so, but at 3000 they still give good fills, and dont have the hassles of the "+" hydros

 

[limeyx]

CD, you just responded to a post almost 2 years old

ha, so did I now -- more than once!
oops.

 

[mictrik]

High pressure Tanks are great as they can carry more air per volume of tank. So if you want 80cf of air. A tank that provides 80cf of air (measured at normal pressure) at 3500 PSI will be smaller than a tank that provides 80cf of air at 2600psi. I personally like small tanks so i use the old Genesis 3500's. They are great, Negative through out the dive and small. I watch my tank get filled every time and try to ensure that i get 3500 - 3700 before i leave the fill station. I try to make sure the tank is cooled while being filled and that it is not filled to fast. When i switched to these tanks in the late 80's (i think) i did not have a problem filling them and often got 3800 fills but now for some reason i notice a reticence on some dive shops to fill higher. With regard to the "abuse" that regulator will sustain at these pressures all i can say is I use a Mk10 / G250 and have not experienced IP creep or any other problem that could be attributed to using higher pressures. I spent a few years in Europe where 300bar pressures are common on SCUBA cylinders and still no issues. In Europe i have used very small negatively boyant doubles that provide 170 cf of air at about 4500 PSI. My favorite tanks (pony sized), they have been around for at least 25 years in europe while here in the USA we were using aluminum floaters that delivered 77.4cf at 3000; we call them 80's "close enough". The old steel 72's were nice but they are getting real old now, but we had to abandon them for these aluminum 80's in order to produce cheaper cylinders. Cheaper = better here in the USA. Anyway for what its worth get the "HP" steels. They last mine are on their 3rd hydro's...