Cant Decide Which New Tank

[Roman_66]

tbone1004

I answered all those questions myself before ordering my tank.
I tried to understand WHY topic started looking for bigger tank than standard AL80.
Between C100 and LP108, probably you are right and LP108 is better, I just never studied LP tanks.
Regarding 3800 psi to 2640 tank, what I can say... I know that a lot of people do it and I never hear about exploding tank because of it.
I also know that tank is tested under much more pressure tank 2640 psi.
But personally I will use only HP for 3000 - 3300 psi and never over manufactory recommendation.
Regarding flat bottom, the solution exists, but unfortunately doesn't have DOT, so is not imported to USA.

 

[tbone1004]

The only LP tanks I hvae are actually 72's that never get filled above about 2800, the others are PST HP tanks, don't have any of the 3442's, but the nice thing with LP's is you are almost always guaranteed a long fill than a short fill, I know with the 3442's, very few dive shops actually give you the full 3500 psi for them. The tanks are all but identical, the factor of safety is just smaller for the HP tanks, that's essentially the only different, this has had many drawn out technical discussions on this board as well as others.
Those concave tanks are problematic because they are really ass heavy and can throw trim off, especially in sidemount and are not abundantly used.

 

[Roman_66]

Those concave tanks are problematic because they are really ass heavy and can throw trim off, especially in sidemount and are not abundantly used.

Here I can't agree with you.
According to link I gave above "Cylinder weight: 14.5kg/cylinder" which is less than 32 lb. - Exactly like most AL 80, but negative than empty.
They are not popular in US, because of DOT, but as I know, popular in Europe.

 

[Lobb4920]

Thanks for the input tbone I have never been told to do that and in makes perfect sense.

 

[tbone1004]

they are not legally allowed to be commercially used in US because of DOT, has nothing to do with popularity, has everything to do with not being able to hydro them.

Tail heavy has nothing to do with total weight, but everything to do with distribution, the couple that I've used/seen actually sit with the valve straight up when they're empty. Normal tanks do quite the opposite and AL80's to a huge extent which is irritating in sidemount, considered normal in stage diving, and helpful to most divers in backmount getting proper trim. Flip that upside-down and they can cause serious trim problems. Kiddie used to make them in 1800 psi tanks way back in the day, and that is the same type of bottom used on a lot of commercial gas bottles.
They can however help to offset the head down tendency with twinset manifolds and drysuits with too much air in the boot, so they are somewhat useful for that, but having dove them before, I much prefer to just throw a boot on the bottom. The 12l tanks are somewhat similar to the LP85's in dimensions, and are about 2lbs heavier, all in the tail. If you want to figure out what it's like, stick a 2lb weight on the very bottom of the tank. It's very strange when you aren't used to it.


Lobb, no worries, one of those tricks that should be universally taught in basic classes but very few instructors even know about. Common sense more than anything, but unfortunately it rarely prevails

 

[Colliam7]

I am definitely leaning toward the LP 108. My local shop usually only gives a hot fill and I only end up with 2700 psi. I have seen a Faber blue steel lp 108 for $334 shipped. I am close to pulling the trigger.

Halt! Take your finger off the trigger, drop the gun and put your hands over your head!

OK, a bit melodramatic. Maybe, a more appropriate admonition would be, 'Stop. Breathe, Think, Act.' You are quite possibly looking at the Faber Blue Steel LP108 on LeisurePro. While it is not a particularly bad deal (although I wouldn't buy a painted faber cylinder, or any cylinder with a Blue Steel valve), you might pause and check out some other options.

1. As tbone said, check out sites for used cylinders. Only one time have I paid anywhere near $335 for a cylinder - the one (and only) time I bought new (a HP steel). I have purchased a number of HP100s for $200, even a HP120 for $250 (and overpaid at that price). Take a bit of time to look for used cylinders.

2. Think about galvanized cylinders, such as the Worthington (XS Scuba 108 Cubic Foot Low Pressure Steel Tank LP108 with reviews at scuba.com - the URL is provided to illustrate the cylinder, not recommend the purchase of a new one.)

3. Think about cylinders with better (than Blue Steel) valves.

 

[tbone1004]

Two sets of LP-95 doubles
If LP95's aren't too short for you, then it may be worth sending Russell a message and making him an offer. I'm heading down that way the weekend of Aug 15 and could pick them up and bring them up to Greenville SC for you, grab a pair of plugs and break them down to singles if you wanted. That way you can keep the bands and the crossbar if you want to move to doubles at some point, you won't have to go scrounging around trying to find those parts, just throw them in the box and set them up at VIP time one year.