one more time, LP tank without + rating

[eelnoraa]

I came across LP80 tank again, all vip and hydro are current, but no + rating. So faber LP80 holds 77 cf at 2640, right? Without the + rating, these tanks hold 69cf, what do you guys think?

 

[captain]

Think about what. Either it is enough for you or not, I dive 72's exclusively and it is enough for me.

 

[Scared Silly]

Ditto think about what? Buying an LP80 without a plus +? If it has the REE stamped on it then get an new hydro and ask for the "+".

 

[eelnoraa]

Oh by what, I am referring to the capacity of the LP80 tank. So is it true that it holds 77cf only at 2640? and at 2400psi, it holds 69cf? If so, these tank almost makes no sense. There are plenty of LP72 with + for much less money, like 1/5 of these LP80. Is there other advantage of LP80 over the older LP72.

The reason I am asking here is that the owner of the tank doesn't really want to answer my questions. His altitue is more like "take it or leave it" I can understand everyone is busy, but as a buyer I also want to know exactly what I am getting.

 

[rstofer]

Let's assume the tank has sufficient capacity, with or without the '+' rating and get that out of the way. If the tank is too small, it's too small.

What you are looking for, if you are diving in cold water, is a tank that is light and as negative as possible. That way you can reduce the weight on your belt and have more of it over your back. That's why the HP 100's are so popular. They weigh less than an Al 80 (and a lot less than a "Neutral" 80) so you don't have to carry the weight and they are 6# more negative at the end of the dive. Oh, and they carry more air; even if they aren't completely filled.

You need to look at tank buoyancy charts like this one:
Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

In no particular order, consider capacity, weight, buoyancy, diameter, pressure and length.

Capacity: you need enough air for the dive
Weight: why hump more than you have to
Buoyancy: within reason, a more negative tank can be a benefit
Diameter: some folks don't like the 8" tanks and readjusting cam bands can be a PITA
Pressure: can you get a complete fill? Low pressure tanks can always be filled properly
Length: too short and the weight is too high, too long and it bumps into things

LP72's aren't really very negative and, I believe, end up neutral or slightly positive. They are great for warm water and fun in the pool. I have one and plan to pick up a couple more.

Worthington HP100s start out 10# negative and end up at 2.5# negative when empty. See:
XS Scuba Worthington Steel Cylinder Specifications

I have some reservations about LP tanks in terms of capacity versus weight. For the moment, I am in the HP camp for cold water diving.

Of course, the problem with steel tanks is cost. I can buy 2 Al 80's for the cost of 1 HP 100. Maybe I don't care if I have to wear 6# more weight just to wind up with only 80% as much air. Or, maybe I do...

Richard

 

[halocline]

I think the LP80 holds a true 80 cft at 2640. I could be wrong, but I seem to remember reading that somewhere. You said its a faber, which means the REE number is right on the tank. You could conceivably find out who did the last hydro (the testor's stamp is on the hydro between the month and year) call them, ask them to look it up, and they should be able to tell you what the total expansion was. If it's less than the REE, they should be able to just stamp the plus.

You could also just live with it until the next hydro, then ask for the plus. I have a friend with a faber LP80. It's like a short AL80, correct? I bet you end up with a lot of 3000 PSI fills anyways.

 

[rstofer]

I think the LP80 holds a true 80 cft at 2640. I could be wrong, but I seem to remember reading that somewhere.

According to the chart I linked above, it holds 78 cf at +10%. Close enough to 80 cf for me!

Richard

 

[eelnoraa]

rstofer: thank for the link. My ideal tank is also X7-100HP, but like you said, cost is an issue, at least for now. I am using Catalina AL80 now. I usually don't go very deep, so I found I am OK with the capacity. Moving toward steel is mainly for bouyancy. I just switch to drysuit, the amount of weight on belt start to annoy me.

mattboy: according to the link above, faber LP80 has 78cf at 2640, so at 2400, it will have 71cf. However, I am not sure if it is the same tank because the info the seller told me is a bit different than the number listed, particularly, the diameter. He said his LP80 has 7". The listed is 7.25".

I am really having hard time communicating with the seller. I want to know what I am buying, but he doesn't seem to want to entertain too many questions. Asking for REE without annoying him is difficult. So looks like I will pass on this LP80. Not sure if he is on this board, I hope I didn't waste his time replying my emails.

 

[Scared Silly]

BITD Faber made some LP80 for ScubaPro that were 7" in diameter. I do not know the exact specs but probably similar to the one they made that are 7.25" in diameter.

With ANY cylinder that has a plus rating you ONLY get the FULL capacity when INCLUDING the 10% overfill. Many get confused over this point but you have it right.

So back to your original question should you buy it over a LP72? In many ways the LP80 is an updated version of the LP72. Faber makes good cylinders. IMHO the reason the lp72 tends to be cheaper is because they are "old", have small "capacity", etc. all of which makes them a good deal. $150 is a reasonable asking price for an updated version. I would buy it over a AL80. Go check out the cylinder and if looks good (including looking at the inside) offer a $100.

 

[halocline]

BITD Faber made some LP80 for ScubaPro that were 7" in diameter. I do not know the exact specs but probably similar to the one they made that are 7.25" in diameter.

So this one might be like a shorter version of a LP85? That could be a very nice tank to dive with, but then again why not just get the LP85?

If you fill a LP72 to 2700 PSI you get about 77 cft, so it sounds like this tank is almost identical in terms of size. FWIW, most of my local diving is done on LP72s and I wouldn't trade them for a newer tank. They weigh 26 lbs empty and are neutrally buoyant, beat that!