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[awills101]

first: i have an old aluminum aqualung tank from 1976 that i picked up for $10 at a swap meet would it be worth getting this tank viz. and hydroed? it was last hydroed in 1984.

second: ill probably be buying a new tank this weekend is it worth spending the extra money to buy a steel tank or should i just go with an aluminum?

third: if i do buy a steel tank how would that change the weight i use? i currently use 28lbs. with a 7mm wetsuit

thanks, Aaron

 

[Fishpie]

No
Yes
6 to 8lbs

 

[Couv]

Hello Aaron,

There are a lot of things consider when buying a tank, how about a little more information on the type of diving you will be doing.

Wetsuit/dry suit
deep/shallow
doubles/single

Fishpie pretty well summed it up, but you may be interested in a bit more detail. AL tanks are not all bad and have been the workhorse for most sport diving.

The main advantage of an aluminum tank is the low cost, which is an issue that can not be ignored; however, because many shops will not fill aluminum tanks manufactured before 1991 even if they pass hydro etc. it is best not to spend your money having the a 1976 tank made "legal." If you like aluminum tanks just get used one from Craig's List with a manufacture date of no earlier than 1991. There are some al tanks with an earlier date that are ok, but I'm pretty sure 1991 and beyond and all free from the dreaded "neck-of-death" issues.

There are lots of threads to read about aluminum tank failing hydro or visual inspections-just do a search and you will have plenty to read. To make a long story short, aluminum tanks manufactured with 6351-T6 alloy frighten (sometimes for good reason) fill station, VIP inspectors and people who sell new tanks. Sell the valve on eBay and the tank at your local metal scrap yard or make something creative out if it like a mailbox or wind chimes.

Steel tanks generally speaking have better buoyancy characteristics. I.e. when steels are empty they are not as positive as an al tanks; therefore less weight is required to compensate for the + at the end of the dive.

Here is a link to a thread about doubles, but DA Aquamaster has put a lot of great information about steel tanks you'll find helpful regardless of diving a singles or doubles.

http://www.scubaboard.com/forums/tanks-valves-bands/271579-right-tanks-first-doubles-2.html#post4193598

couv

 

[Scared Silly]

For item #1 Do a search on 6351 cylinders and you will find that they are more hassle than they are worth. But given that you paid all of $10 take it to your scrap yard and you will probably find you can earn 30% on your investment.

 

[halocline]

Fishpie was right on the first point; you'll never get it filled.
On the second, it depends on how important the money is to you, as well as what kind of price you're talking about, but absolutely if you're using 28lbs of lead you will prefer a steel tank.
For the third, 6-8 lbs is an oversimplification, as the buoyancy of steel tanks varies quite a bit by size and manufacturer. Here's a good chart:
Scuba Cylinder Specifications from Tech Diving Limited - 928-855-9400

 

[RonFrank]

Your first tank purchase will likely be a wash as I doubt it will hydro, but you may get a bit more than you paid in scrap.

As such a new diver, you may want to dive a few different tanks to see what you like. A Steel 100 might work well for you if you are not a great breather. A Steel 80 is a lot less expensive, but the tank profile is a bit weird (small/heavy).

My guess is you are overweighted at this point. Once you settle into diving, I'm betting you can drop a few pounds, and quite possibly a LOT of pounds! They started me out with 28# of lead in a 7mm fresh water! My guess is that it would have been 35# in salt! :shocked2:

I now use 20lbs, but with a dry suit with undergarments! I'm guessing I could do 10lbs in a 7mm fresh, so yes, they totally overweight new divers. They want NO issues with them trying to sink, or soaring the surface as they suck down the tank.