Want to buy my first air cylinder

[Mr. Ed]

When I complete OWC I want to buy first air cylinder, I am considering a steel container, but I am unclear of differences between high and low pressure and which one is best suited for me.

it seems steel cylinders require a lot of preventable maintenance?

i prefer steel over aluminum based on size, weight and buoyancy.

Your thoughts and experience appreciated.

Mr. Ed

 

[Jim Lapenta]

There are pros and cons to steel. Though for many of us, the pros far outweigh the cons.
The first con is the initial cost. Often twice as much as an aluminum. Second is the wide variety of choices.
However, that is also one of the pros. For "main cylinder(s)" anything from 50 to 130 cu ft is possible. With those lower ends usually being combined as doubles or sidemount pairs.
The choice of LP vs HP is personal and dependent on a few factors.
1. Can your supply source fill HP cylinders and will they give you a good fill. If they have a practice of filling to 3000PSI and that's it, the HP cylinder is a waste because you'll never get a good fill. A HP 100 is only 100 if it's filled to 3442. At 3000 it's only 87 cu ft. A LP 85 is 85 at 2640. If you find a shop that fills steels with a bit of generosity and they take that 85 to 3000 or even 2900 it's now carrying 96 cu ft @ 3000.
Steel cylinders, as long as they are not completely drained require no more maintenance than an aluminim. Pop the boot off, rinse, allow to dry and you're done. Some boots don't need taken off if they drain properly.
Choosing the right one for you is going to depend on primarily to begin with, your budget. If that's not a factor then you need to determine what your air consumption is and what kind of dives you plan to do.
For many of my local shallow sites a steel 72 is fine for me for 2 hour long dives.
Deeper stuff like the great lakes and deeper quarries I dive then the smallest I want is an LP95 and those are usually filled to 3400 for those dives. Effectively giving me 120 cu ft of gas.
I only own and dive LP cylinders because I am pretty much guaranteed to get a good fill. At some of the quarries when they get busy they fill from 3000 PSI banks or they say they don't have time to put 3400+ in a HP cylinder unless you want to leave it overnight.
If I get a 3000 PSI warm fill it's only going to cool down to maybe 2700-2800 which means I still have a full cylinder.
Also, steel cylinders have a much longer life span. A number of shops won't fill aluminum ones more than 20 yrs old regardless of the alloy. They just won't. I've got steel 72's from 1954, 1956, and 1970/71 that still pass hyrdo and get filled with no questions asked. In the long run they are cheaper.
If you are going to buy a tank, might as well buy 2 right off the bat. Unless you know you are only going to do one or two dives and call it a weekend you'll wish you had a second cylinder filled and ready to go so your don't have to wait in line for a fill or rush back to the fill source before they close to dive the next day.

 

[Angelo Farina]

I own a Faber steel, 15 liters, 200 bar. It is more than 30 years old now, and looks as new.
Cressi dual-valve with reserve (reversed T), which allows me to use two fully independent regs (two first stages, two identical second stages) for maximum redundancy and reliability. Dual-purpose posts (DIN and INT), of course I use DIN, after having converted several of my old Scubapro MK5s with the original DIN conversion kit.
Perfect balance in water, proper amount of air (3000 liters, I do not know in Cuft) for most recreational dives ( I do not exceed 40m since at least 20 years, so my twin set is getting dust in the garage).
With this tank, I did never need to use my 3-liters pony tank in the last 20 years.
If buying new, I could be tempted by a 15 liters 232 bars, as my son's one. More weighty, but you can save a couple kg of lead in the belt, so in then end it does not change a lot. And in many places nowadays they can fill at 232 bars...

 

[TMHeimer]

I had a steel '72 from 1976 that I used until maybe 10 years ago. Sold it in favour of larger tanks. My first tank was a steel 120. Great in the water, not so much walking around. I currently own 4 AL 80s which are the right amount of air, and I need not change my weight going from tank to tank. They are all from the early '90s and pass visual each year at the shop, so I don't know how long they may last.

 

[broncobowsher]

Buy 2
Actually great advice. Not sure where your local dive sites are at. Because that is where you will be bringing the tank to. Tanks travel great by car, not by plane. So local is where you will be using it at. Most of the time people will show up and do a 2-tank dive. Weather it is a boat ride or a local quarry. About the only time owning 1 tank makes sense is if you own a boat and just want to have an anchor recovery rig.

 

[Mr. Ed]

Good advise everyone, much appreciated!

 

[Mr. Ed]

I’m considering a Faber 100 cu ft galvanized spray steel cylinder. When buying online are valves included or bought separately? Black Friday/Cyber Monday sale.

 

[broncobowsher]

Depends on why you buy from. If it says "valves included", you get some. If not, they typically don't come with the tanks.

Reason being is people often don't want the standard valve. Upgrade to a DIN (or DIN compatible/Pro) valve. Maybe a manifold to make a set of doubles. Or just a left and right valve for doing sidemount. There are several versions of valve that exist. Sites like DGX will put option boxes on the tank ordering form so you can add the valve you would like to get with the tank.

 

[Marie13]

I’m considering a Faber 100 cu ft galvanized spray steel cylinder. When buying online are valves included or bought separately? Black Friday/Cyber Monday sale.

Tanks rarely go on sale. There’s not much profit margin so don’t expect to get a deal. Plus there have been supply issues with the Faber steels as they come from Italy.

 

[Mr. Ed]

Can’t decide what to choose high pressure or low pressure steel cylinder? If I wanted to buy two smaller steel cylinders and a BCD that accommodates two cylinders, the smaller cylinders would likely be low pressure?

The other option is buy a single 100 cu ft high pressure cylinder and use my existing BCD that will likely replace anyway?

Are backplate BCD’s easily modified to manage duel steel cylinders and single larger steel cylinders?

What are the differences between backplate material, composite, steel, aluminum?