Air cylinders

[CuzzA]

At the risk of starting a 50 page thread ...wouldn't you agree the "unsafe" perception is an illusion created by the DOT and not necessarily the strength of the tank?

 

[Slym]

hm beyond price of course, I wonder why they don't make titanium tanks, a super light metal certainly stronger than aluminium but not as much as steel, seems ideal really if somebody were willing to pay the price

 

[TheHuth]

I'm not a metallurgist, but I would think Titanium tanks would be very unsafe. Titanium is a brittle metal. One good drop, and it would pop like balloon....filed with shrapnel

Based on what I'm reading, there is no real up side to aluminum. With steel there are two choices, hp and lp. Why choose one over another?

 

[PfcAJ]

hm beyond price of course, I wonder why they don't make titanium tanks, a super light metal certainly stronger than aluminium but not as much as steel, seems ideal really if somebody were willing to pay the price

still need ballast to sink

 

[Slym]

I'm not a metallurgist, but I would think Titanium tanks would be very unsafe. Titanium is a brittle metal. One good drop, and it would pop like balloon....filed with shrapnel

haha A very good reason why I am becoming an electrician and not a millwright

 

[The Chairman]

At the risk of starting a 50 page thread ...wouldn't you agree the "unsafe" perception is an illusion created by the DOT and not necessarily the strength of the tank?

Not in public, I wouldn't.

 

[seeker242]

Based on what I'm reading, there is no real up side to aluminum.

I think the upside is just that it's less expensive.

 

[Bob DBF]

Based on what I'm reading, there is no real up side to aluminum. With steel there are two choices, hp and lp. Why choose one over another?

The up side of aluminum is the price. Also there are a lot on the used market. When I originally purchased, I needed two tanks because of the logistics of making two dives and getting a fill with no fill station close to the dive site. At the time, two new Al tanks cost about the same as one steel tank and I had a budget, also there was no used market to speak of.

After that, I picked up used steel tanks as they are better because it is less weight on the belt, and I get bigger tanks than the Al80.

LP tanks are good if you have a problem getting a good HP fill. I use a LP 95 on boat dives where they hot fill and may not have time to top off. If the fills are 27 to 29 hundred, every one is short but me. Cave country likes them because they can get overfills.
The HP 100 is a nice tank and reminds me of the vintage 72. If I could only have one tank in my inventory, that would be it, lucky for me I don't.
I really like the old Faber MP tanks, both the 3000# service (3300# with +) and 3180# service (3498# with +), all the ones I've tried have been great to dive, but finding them to buy is another story.


Bob

 

[NAM001]

buoyancy is the main difference as application goes. The general rule is al for fresh water and steel for salt.

Each tank has a purpose and that purpose varies between divers needs.

 

[NAM001]

I'm not a metallurgist, but I would think Titanium tanks would be very unsafe. Titanium is a brittle metal. One good drop, and it would pop like balloon....filed with shrapnel

Based on what I'm reading, there is no real up side to aluminum. With steel there are two choices, hp and lp. Why choose one over another?

Ballasting for buoyancy and for trim uses tank position to accomplish. if you have to have a tank sit low to stay horizontal and you have a short tank you cant get to the valves. In that case use taller tanks. If yo have a choice of having an lp95 or a hp100 and you can only get a 3000 psi fill, in your area, you are way short of having a full tank with the hp100 and have another 10-15% in the lp95. a lp95 at about 3000 psi is about 108 cuft. a hp100 at 3000 psi is about 80. lp's are heavier but if you ocean dive the neg buoyancy allows you to not use a weight belt to the degree you would with a lighter tank. If you double up lp95's, they have a tendency to be top heavy (if you are tall). they are short tanks. hp100's are longer tanks and lighter. i think about 33# compared to 42 on the lp's empty. If you dive with wet suit the tanks will comp for the suit. if you dive with no suit than the tank weight / buoyancy can be your demise.
100s are smaller and more streamline than Lp's.

Up side to aluminum is that if yo dive with no suit than the al tanks have minimum neg buoyancy. Once you put on a reg they are just about 0# mt. more upsides are they are relative cheap and after a few years you can throw them away. They don't rust like steel so is some cases they can last longer. especially if you band them for doubles. If you dive them in the ocean you can get salt water corrosion as opposed to visual red rust.

If you are a small person then al tanks may be the est for you. if yo are a lumberjack type then perhaps lp120's is needed to counter ballance the positive lift of the body.

Heavy tanks on the back will tend to make you roll over so the lighter the tank the more you can remain face down. larger people dont usually have problems with this.

Selecting the right tank can be just as hard as selecting the wet suit that will fit you.