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ontheheap
10-23-2009, 00:51
I have only used steel 80's so far, but was thinking of purchasing/trying an aluminum tank. I'm currently using 10lbs of weight for fresh water dives with the steel tank (though I think I'm a bit overweighted, actually). I've never used an aluminum before. In expect that I'll need to add more weight to make up for the difference between the materials.. is there any way to sort of guestimate the amount of extra weight I will need if I make the switch?

nrembis
10-23-2009, 00:58
will be best for you to do a quick weight check, but more than likely will be about 6lbs additional

ontheheap
10-23-2009, 01:06
Yea I'll definitely do a quick weight check. Thanks for providing me with a starting point!

CompuDude
10-23-2009, 01:55
Look at the bouyancy figures for your tank, measured empty (to simulate your lightest weight, at the end of a dive). Compare that to aluminum tank figures.

Most steel 80's (I assume LP?) are approx 1-2# negative. Aluminum 80s are 4# positive. The difference is about 6#, so yes, there is your starting point.

Scuba Cylinder Specifications from Tech Diving Limited - 928-855-9400 (http://www.tdl.divebiz.net/pub/tanks.html)

maverick
10-23-2009, 18:18
I went from Al80 2 steel80 and like steel better.

Tassie Diver
10-23-2009, 19:53
See if you can borrow an ally tank, before you buy one.

Pretty much everyone I dive with started on Al80s and then went to Faber steel 100s (12.2L/232bar).

Why do you want to go aluminium?

ratown
10-23-2009, 20:17
Definitely try one out first. They dive way different. I'm interested in why you're switching too.

underh2o
10-24-2009, 06:39
I dive steel 100's doubles and singles. Love them. But I do SAR. I dive AL80 then. I always dive over weighted when not joy diving. This way I stay low and deep on the bottom. AL80 great thing is in the blackwater I dive 90 % of the time I can not see my guages. I always dive a pony bottle and I been known to suck a tank empty YOU CAN NOT DO THIS WITH A STEEL. Then grab the pony and come up. but then a gain steel carry their own weight(you use less weight) like compudude said. AL80 are esier to manitain but steel are still better. Most people start with AL then go to steels. But, you need to make the final decision. You can always sell steels and make a good portion of your money back. But like everyone said you need to try AL before you buy.

CompuDude
10-24-2009, 21:15
I dive steel 100's doubles and singles. Love them. But I do SAR. I dive AL80 then. I always dive over weighted when not joy diving. This way I stay low and deep on the bottom. AL80 great thing is in the blackwater I dive 90 % of the time I can not see my guages. I always dive a pony bottle and I been known to suck a tank empty YOU CAN NOT DO THIS WITH A STEEL. Then grab the pony and come up. but then a gain steel carry their own weight(you use less weight) like compudude said. AL80 are esier to manitain but steel are still better. Most people start with AL then go to steels. But, you need to make the final decision. You can always sell steels and make a good portion of your money back. But like everyone said you need to try AL before you buy.

What is it that prevents a steel tank from being sucked empty?

(I agree it's not a good idea with any tank, in general, but there's nothing specific to the metal a tank is made from that prevents this)

ontheheap
10-25-2009, 00:39
I don't really have any specific reason for thinking about going with aluminum. I just got started with diving a month or so ago and I'm still sort of trying to figure out what equipment I like and don't like. It seems I'd probably be better of sticking with the steel80, but before I actually purchase a tank I'll rent an aluminum and see how it goes.

WD8CDH
10-26-2009, 07:23
AL80 great thing is in the blackwater I dive 90 % of the time I can not see my guages. I always dive a pony bottle and I been known to suck a tank empty YOU CAN NOT DO THIS WITH A STEEL. Then grab the pony and come up.

Sounds like you need a J valve.:smiley5:

On some of the SAR dives that I have done, I would never take the regulator out of my mouth.:smiley11:

Lone Frogman
10-26-2009, 08:33
I dive steel 100's doubles and singles. Love them. But I do SAR. I dive AL80 then. I always dive over weighted when not joy diving. This way I stay low and deep on the bottom. AL80 great thing is in the blackwater I dive 90 % of the time I can not see my guages. I always dive a pony bottle and I been known to suck a tank empty YOU CAN NOT DO THIS WITH A STEEL. Then grab the pony and come up. but then a gain steel carry their own weight(you use less weight) like compudude said. AL80 are esier to manitain but steel are still better. Most people start with AL then go to steels. But, you need to make the final decision. You can always sell steels and make a good portion of your money back. But like everyone said you need to try AL before you buy.

I can't imagine that style of back water diving. Diving till you run out of air in backwater. Who did you get your training with? On our dive team, if you come up with less than 1000psi, you may find yourself off the team. Our dive times are limited to 20 minutes or less depending on air. I dive with hp steel 100's. Never get close to using half the air.
I find by putting my SPG in a clear plastic bag filled with clean water and sealed off on my hp hose with a zip tie. Depending how bad the water is, you may not even need the bag. You can shine your light on your gauge to illuminate it and then press it against your mask to read it.

longtailbda
10-31-2009, 06:57
I use Al for diving with traveling and for stage bottles. For local fun dives I prefer sticking with steel due to weighting.

jupitertreasures
11-10-2009, 07:16
Why would you go from steel to AL....unless you travel with your tanks.
Most folks go the opposite route....from AL to steel.

mm2002
11-13-2009, 05:48
The only reason I've heard of anyone going from steel to al was to have more ditchable weight. In your case, though, from steel 80's to al 80's, the difference wouldn't be huge (around 4-5 lbs). With HP 100's or larger, you'll likely have no ditchable weight (depending on diving conditions, exposure protection, etc)

thor
11-13-2009, 13:04
Just out of curiosity, how did you end up starting to dive on steel tanks?

rednose83
11-13-2009, 14:23
Just out of curiosity, how did you end up starting to dive on steel tanks?

I'm not the OP but one on my LDS uses steel tanks for OW classes.

Damselfish
11-13-2009, 15:18
ditto, it's been a long time but the LDS I did OW with we used steel. I then bought AL because they were cheap, but if I'd kept diving locally for longer I imagine I'd have moved back to steel. (Cold water - in warm water I'm pretty much overweighted with a steel tank.)