Steel Tank question, vs alum.

[Jimmer]

Dosent all aluminium build up a layer of oxidation? If its such a problem why are the outsides of ali scuba tanks not covered in a protective paint layer and why dont ali boats corrode away?

Yeah 99% of the time aluminum oxide will be a protective layer. It can however get excessively thick if the tank is filled with bad air. The chances of that are slim to none. If it does get too thick it can flake off in the form of a white powder, and really isn't good for your health. Like I said the chances of it being an issue are virtually nil. If you had that much bad air, you have bigger problems. As for tanks being unprotected, most of them are clear coated to prevent there being an issue, even tho they are "bare aluminum". I've seen painted AL cylinders that got a slight nick in the paint and sooner or later they had a build up of the white oxide in that location. Either way it does happen, but it's not a big deal.

 

[cummings66]

Dosent all aluminium build up a layer of oxidation? If its such a problem why are the outsides of ali scuba tanks not covered in a protective paint layer and why dont ali boats corrode away?

There are many forms of corrosion when it comes to aluminium, my buddy lost his airplane due to that. The internals were so rotten it was scary and it failed an inspection, to be fair it was near the ocean so it has been exposed to salt air.

Yes, it does build up a layer of protection but that doesn't mean it's safe from that point forwards, it can go much deeper and pretty quickly.

Just ask any owner of an airplane what his major concerns are and corrosion will be listed right up at the top, especially if he's on the coast. It's such a major issue we have special coatings that many apply during annuals every so often that reduce the corrosion which occurs. Do you know what almost every owner will ask the prebuy mechanic to look for? Wing spar corrosion. It's serious and has killed more airplanes than pilot error.

Working at a store which also sells boats I can tell you first hand that they also corrode, and I have seen scuba tanks which had a bare outside form corrosion. It really does happen.

 

[JR Max]

I like steel Faber 120 cu ft low pressure tanks. I weigh 260 lbs, and 6'2" tall..So the size and weight of the tank is right for me..The low pressure tanks are made of the same steel that high pressure ones are made of...I also like the low pressure steel tanks as you very seldom get a low fill from a dive shop, and most of the time get extra fill pressure. So if you are a large person, the 120 cu ft LP steel would be best. If a regular size person, the 108 cu ft LP steel would be best..FYI, there is only a minimum difference in costs between the two tanks. Most also come with a convertible tank valve (DIN to yoke).I enjoy very good bottom time with my tanks. If you care for the steel tank it should give you 30+ years of service, aluminum tanks don't hold up as long.

 

[chipwd]

choose to go with a steel tank instead of AL for a few reasons not in any particular order:

1. Wanted a bigget tank. I could only find AL 100s
2. Steel Tanks last longer in general
3. I liked the buoyancy qualities of steel tanks when empty... I wear very little weight and AL tanks make me more positive at the end of a dive than I like.

I'm sure there are other reasons to buy a steel tank, but those are my reasons... You should really consider what your needs are and go with what's best for you.

Steel worked out better for me.

I agree with wysmar. I found that when I was a newer diver I "hoovered" air and the HP100 gave the extra I needed to be able to dive with much more experienced buddies diving AL 80s. I wasn't the first to call a dive due to low air.

I also like the weight I can take off my belt with the steel tank. Diving cold lake waters the majority of the time in 7mm farmer john makes for a lot of weight to carry. The 4 or so pounds I don't carry due to the steel tank helps.

I also like the size; a little shorter than an AL 80 and fits nice and compact on my back. My tanks came with pro valves so I can dive din or yoke. (I dive din)

I now have 3 HP 100's.

 

[texspeleo]

Your trim in the water is a very personalized thing, but I feel that generally a diver is the most effecient and under the best control when the head is slightly below the fins in a horizontal plane. I was introduced to this as a concept in a cavern diving course, but I also find that I prefer it in open water. Cavers use it primarily to ensure that their fins stay out of the silt on the floor, but it's also nice for keeping your fins (and fin wash) away from the reef as well. You're a lot less likely to bash your face against someting. A steel tank does take some of the weight off of your belt and places it higher on your torso, which makes this position easier to maintain. I like Faber 95s and PST 104s personnally, but I'd try out as many as you can get your hands on.

Cheers----Chris

 

[squidster]

Were in colorado can i get a faber tank?

 

[CompuDude]

Were in colorado can i get a faber tank?

Online.

Seriously, there may be some local shops that carry them, but I wouldn't know, as I didn't dive when I lived in CO. Try www.techdivinglimited.com and if you're not in a hurry keep an eye out because Joel and Randy have sales very frequently.

 

[TSandM]

The decision about what tank to buy is made by considering a number of factors:

a) Capacity
b) Bouyancy characteristics
c) Longevity
d) Cost

I listed capacity first, but it's probably the most potentially misleading. New divers often want to buy much more capacity, because their gas consumption is high, but it's quite possible to end up with a tank you don't like diving at all in the search for MORE. One of my dive buddies did this -- He bought a large steel tank that was incredibly negative, and he could not adjust his trim to horizontal while using it. It was eventually sold. Most people would advise to buy a tank of reasonable size and better buoyancy characteristics, and accept that one's dives will be shorter than ideal until one's gas consumption falls with experience and better technique.

What is acceptable or desirable in terms of buoyancy depends greatly on where one is diving, and what exposure protection is being used. When I dive in the tropics, an Al80 is entirely acceptable to me. It requires about six pounds of weight, which is something I'm willing to carry, and CAN carry in such a way as to be able to maintain horizontal trim. In Puget Sound, in a drysuit, I have to carry 38 pounds to sink an Al80, and that's more than I'm willing to do, and more than I can easily distribute correctly. If I dove fresh warm water, the steel tanks I dive in Seattle would most likely be too negative, so that I could not achieve the state of being neutral at the surface with 500 psi and an empty wing.

The physical size of tanks can become quite important when you dive doubles, but I don't think that's nearly the issue with a single tank.

Steel has a much longer life than Aluminum, but unless you are sure you're going to be diving for 30 years, that's probably not a high priority consideration.

Steel tanks are considerably more expensive than aluminum, which can be a significant factor for new divers, who are in the process of laying out the considerable amounts of money required to get into their own gear.

Putting weight on your back will not make you unstable or make it harder to swim. It may well make it EASIER, in that you will find you tend to be more horizontal. However, if the tank you select is too large and too negative (big Fabers) you may end up with the opposite problem, being head heavy. (This is what happened to my friend.)

 

[CompuDude]

Steel has a much longer life than Aluminum, but unless you are sure you're going to be diving for 30 years, that's probably not a high priority consideration.

Steel tanks are considerably more expensive than aluminum, which can be a significant factor for new divers, who are in the process of laying out the considerable amounts of money required to get into their own gear.

I would add one thing and one caveat to this: Steel tanks also tend to have a much higher resale value than aluminum, should you decide to get out of diving. The caveat is that the tanks must be taken care of well, because if you overfill the heck out of them and they fail hydro, that expensive tank won't be worth beans.

One advantage to the higher resale, however, is the prospect of working your way up to shiny new tanks. Start buying used tanks, treat them well, and you can probably resell them for close to what you paid, and later apply that money towards a shiny new tank of your very own.

 

[texspeleo]

I don't know who carries Faber around here. I bought mine in Austin, TX in the early '90s. Ebay is a bit of an expensive gamble, for something like a used tank. I doubt that you would be able to recover your money very easily if you bought a tank that couldn't pass hydro. I seem to recall something about Scubapro buying Faber, but I'll have to do some research. If that's the case, any Scubapro vendor should be able to get them. I do like Scubapro's steels, but don't own any.... I'll do some looking around.
Cheers----Chris