PDA

View Full Version : Steel or Aluminum?



james.earnhardt
09-03-2007, 04:40
I was on a budget so I bought a 30.00 tank of ebay. When I received it I found the DOT stamp was stamped 1972. With that said I went to the dive shop here in Greece to buy another one and they are all for steel tanks. I told them I wanted an aluminum tank and they almost kicked me out of the store. Is steel really better than the aluminum for bouancy. If that is the case should I buy a neutral buoyancyaluminum tank. The water has a lot more salt content than in the states maybe that is why they are wild about steel tanks here.

Aussie
09-03-2007, 05:10
I was on a budget so I bought a 30.00 tank of ebay. When I received it I found the DOT stamp was stamped 1972. With that said I went to the dive shop here in Greece to buy another one and they are all for steel tanks. I told them I wanted an aluminum tank and they almost kicked me out of the store. Is steel really better than the aluminum for bouancy. If that is the case should I buy a neutral buoyancyaluminum tank. The water has a lot more salt content than in the states maybe that is why they are wild about steel tanks here.

Hi James,
Did you get the ebay cylinder hydrostatic tested? It might be still good? got yourself a good cheap cylinder.
You in Greece, Europe?
Faber steel cylinders are very popular in Europe and Australia with the faber 12.2litre 232 bar (100cf)the most common choice. Its the same size as an 80cf Aluminum. Buoyancy characteristics of the Faber 232bar steels are that they are roughly 3lbs heavier than Aluminum. This means you can take 3lbs off your belt. I havnt come accross neutral buoyant aluminum cylinders over here but know that certain brands of aluminum cylinders have different buoyancy charactoristics. Luxfer are more neutral and Catalina's more positive.

Aluminum is very popular in the tropics, especially with the issues for rust etc etc. Luxfer cylinders have a 15 year warranty which is also good to know. I would say over here Aluminum cylinders to steel cylinders would be roughly 10:1

Aussie

Manny-R
09-03-2007, 19:52
steel tanks are good because they all (for the most part) stay -buoyancy wise even when empty, so that means you can take weigh off the belt, and the steel tanks are also lighter than aluminum tanks.

Kidder
09-03-2007, 19:57
I like the steel for the air capacity. On shallower dives where nitrogen is less of an issue steel would be cool for more under water time. I am going to get one when I can afford it.

skdvr
09-03-2007, 21:22
I would get the tank Hydro'd because it very easily could still be a good tank. It just depends on how well it was taken care of before you got it. I would not be worried about diving steel tanks in Salt Water again you just have to take care of them. They will last a very long time. I do not like the Neutral AL 80's. They are a heavy tank for only being Neutral when empty, and their full fill pressure is 3300 PSI so if you go to some place that will only fill to 3000 then you are short (it would only have 70 cf). A lot of places will just notice that it is an AL 80 and fill it to 3000 and then when it cools you are at 2800 or 2900 and that would be very short for a 80cf cylinder that is supposed to be filled to 3300.

I dive with a steel HP 130 and if I get a short fill of only 3000 PSI at least I still have 115 cf of air. Not that I am happy with a 3000 PSI fill but sometimes when they are hot filling them that is all I am going to get unless I want to sit around for an hour to get a fill...

Stick with steel tanks and you will be happy with them. There is nothing wrong with AL 80's either, I just do not like the neutral 80's

Phil

CompuDude
09-04-2007, 17:16
Aluminum tanks are fine for warm water, and for cold water, well, they're not as good, but they work and they're cheap.

Steel tanks have vastly superior buoyancy characteristics, however, for colder water use. They'll generally last longer, too, although they require more care.

If you have a tank already, and you've dove it and are happy with the way it works, you're all set. If you have the cash to spare, and want to trade up, there will be benefits... at a cost, of course.

starsfan96
09-07-2007, 22:26
Yeah about hydroing the old tank it is definatley worth your time, my dad just re hydroed his old tank he bought in like 78 or so i cant quite remember, anyway he used it for about ten years then took about 15 years off, and then started diving again when i got certifed. Got the tank stated and vis. inspected and it passed and it works great, i've dove w/ it as well as my brand new tank and i cant tell the difference.

reefugee
09-08-2007, 14:34
What extra maintenance does a steel tank have over an aluminum tank?


They'll generally last longer, too, although they require more care.

divinginn
09-08-2007, 15:01
What extra maintenance does a steel tank have over an aluminum tank?


They'll generally last longer, too, although they require more care.

none,just a good rinse after diving,keep a eye on rust under the boots,it would help to pull the boot off and rinse there to prevent rust. i have a steel tank i have been using since 1980 and it was used when i got it,did have to repaint it recently though.

Charles R
09-08-2007, 15:03
I prefer steel just to get the weight off my belt and on my back!

cummings66
09-09-2007, 08:18
That's why I like steel. Steel tank capacity can be smaller or larger than an AL tank so capacity doesn't have much to do with why you'd want a steel tank.

To be honest, if weight is the primary concern then a steel HP100 is what you want. If volume is then look for the HP120's or larger, the HP120 is a good compromise tank. Just be aware that HP tanks often don't get a full fill and so the HP100 might have 80 cf of gas in it.

CompuDude
09-10-2007, 14:00
That's why I like steel. Steel tank capacity can be smaller or larger than an AL tank so capacity doesn't have much to do with why you'd want a steel tank.

To be honest, if weight is the primary concern then a steel HP100 is what you want. If volume is then look for the HP120's or larger, the HP120 is a good compromise tank. Just be aware that HP tanks often don't get a full fill and so the HP100 might have 80 cf of gas in it.

I would modify to use HP119s for the smaller size diver, since 120's are so long they give many people trouble trimming out in them, but yes.

I'm 6'3" and I don't care for 120s too much... I prefer the 119s. I know divers who are 6'0" who use them and like them, however. but I find the length of the tanks to be more trouble than it's worth. HP119s are the same height as HP100s, just fatter. (8.0" vs. 7.25")

Agree that HP100 is probably best to reduce weight on the belt. Once you take a step up from there, the weight of the tank itself goes up dramatically. (dry land issue only, not an issue in the water, of course)

CompuDude
09-10-2007, 14:13
What extra maintenance does a steel tank have over an aluminum tank?


They'll generally last longer, too, although they require more care.

You have to be extremely vigilant about rust, far more so than with Aluminum.

This includes inside the tank. If the boat crew is not good about blowing out water in the valve before hooking up the fill whip, they'll blow moisture inside the tank.

Those few drops of moisture inside will do FAR worse damage to a steel tank than an aluminum one.

cummings66
09-12-2007, 11:04
It would be good for any owner of a steel tank to learn the care and feeding of them. You've got to be religious in how you use them and get them filled, don't trust anybody who fills them to blow the valve out, or whip. Do it yourself and you know it's right.

PS, I'm 6' and the HP120's are just long enough to trim me out properly. A shorter tank will usually have me head heavy, I only carry 8 lbs of lead in a drysuit for fresh water so I can't put too much weight up high, the HP100 I have makes me a little head heavy and at stops it means I've got to move away from horizontal or I'll end up doing the stop upside down. The HP120 lets me stay horizontal which I like. There's no way to move weight lower for the HP100 and I live with it being like that when I use that tank.

It's not badly out of trim however, it's so close that you will ever so slowly find the feet moving upwards. When I'm trimmed right it's like being on a teter totter, I can move the feet up or down and change trim. I just wish I could do that every single dive at every point in it, but I'm just not quite there yet. Close enough it doesn't bother me, but not what I want yet and I'm still working towards perfection which I'll never get.

Special K III
09-12-2007, 15:40
Some guys have suggested you have that 1972 tank tested and hydro'ed. My opinion is dump the 35 year old tank. If you buy Aluminum, special order up a neutrally bouyant tank. Best of luck. :smiley20: