Stainless Steel Tanks?

[rjack321]

Okay I bit but no luck. "rock bottom"?

Sorry, I was trying to avoid opening another thread on the topic.

Rock bottom is the gas it takes 2 stressed divers to ascend while making a reasonable number and duration of stops (for me that's a 1 min stop per 10' starting at 50% of depth)

Roak was nice enough to post some links to relevant threads.

HP80s are just too small for me (and reserve gas for my buddy) below 60ft. Above that and I get about 50 mins to an hour out of one.

 

[GDCB]

Sorry, I was trying to avoid opening another thread on the topic.

Rock bottom is the gas it takes 2 stressed divers to ascend while making a reasonable number and duration of stops (for me that's a 1 min stop per 10' starting at 50% of depth)

Roak was nice enough to post some links to relevant threads.

HP80s are just too small for me (and reserve gas for my buddy) below 60ft. Above that and I get about 50 mins to an hour out of one.

Thanks I appreciate the consideration. I had your collective ears and didn't want to start a new thread. I broke this thread awhile back when I went to tank buoyancy. What you did was further this discussion. All of this pertains to my question of tank purchase. Gas planning is something I had'nt given enough consideration. Now the compact AL 80 would be good for my GF who has been using a AL 63 and I need a 100 or better.

Good stuff, keeps me thinking/learning.

Carl

 

[agilis]

"slope " brings up other connotations, like a bad dream from another time in my life. Any mathematician understands the use of the term "curve". It has nothing whatsoever with a deviation from a flat line or surface. It's a trigonometric construct, a descriptor. However, I promise to avoid its use if it creates problems.

The point of this thread was "why no S/S tanks?". I think that has been answered, as has the difference between hp80s & traditional al80s. Price seems to be the main issue there., along with using only one type of cylinder. Another issue, interjected and not part of the thread, is the contention that 80c.f. is not enough air, in whatever container. That, it seems to me, is a personal choice reflecting gas management and the kind of diving one does. I seldom dive deeper than 60 feet, usually return with 800 to1000lbs. I do a lot of rocky shore entries. Steel hp 80s are just perfect for me. Certainly not for everyone.

 

[fire_diver]

the tank weights are terrible for me. I tried one on and AL80 and it threw my balance off so much that I couldn't swim anything other than vertically. I stick with AL80's cause they are cheap and everywhere, I have bought a couple of used ones now and haven't paid over $100, and that's after the money for the Hydro and VIP. Basically my thought is, if I always dive the same basic cylinder then I have one less thing to screw with when I travel.

Are you talking about those crappy "weight lifters" weights that are held under a tank boot? I don't doubt you had problems with one of those. AL80 users should instead be using a weight on a seperate tank strap. It removes the positive bouyancy of the tank when empty, plus it can be positioned on the tank to HELP your trim.

FD

 

[meesier42]

Are you talking about those crappy "weight lifters" weights that are held under a tank boot? I don't doubt you had problems with one of those. AL80 users should instead be using a weight on a seperate tank strap. It removes the positive bouyancy of the tank when empty, plus it can be positioned on the tank to HELP your trim.

FD

Yup those stupid things are what I tried, luckly I didn't have to buy it. The thing I used to do was clip a 3lb ankle weight about the bottle neck. But then I got a BCD with trim pockets and I dumped the ankle wieght.

 

[royalediver]

Nickel and chrome are two major components of SS and today the price of nickel is $12.06 per lb. All my studies tell me that ss in high pressure cylinders is that is is unsafe as it is extremely brittle and unpredictable due to the inability to get a refined grain structure within the metal.

 

[rjack321]

Nickel and chrome are two major components of SS and today the price of nickel is $12.06 per lb. All my studies tell me that ss in high pressure cylinders is that is is unsafe as it is extremely brittle and unpredictable due to the inability to get a refined grain structure within the metal.

I don't get it. The vast majority of my compressor station is 316 SS. Working pressures in the 3500 (manifold) to 9000 psi (tubing) ranges depending on the part. I have hoses with a SS braid and they are flexible and have a WP of 3000 psi.

Most of the solid parts have a 4x safety factor (burst from 12,000 psi on up). So SS can be plenty strong and not necessarily brittle either.

Is there something about how steel cylinders are made that is incompatible with SS?

 

[GDCB]

Yah, I'm a bit confused too. I know some of the SS steam systems I've worked around held pretty high pressure and went through lots of work cycles. I KNOW SS WILL WORK HARDEN AND GET BRITTLE BUT....the movement from air fill cycles is pretty minimal. As always I'm still learning.

Carl

 

[royalediver]

This goes back many years ago when Dacor was trying to intoduce a Justus stainless tank. It never developed beyond prototypes. my understanding was they could not get the blank to draw in the die without developing "hard spots" and when trying to heat treat the cylinder could not get a refined grain structure within the cylinder.

 

[rjack321]

Thats what I figured