Posted by John Walker on January 22, 2002 at 17:21:10:
In Reply to: John Walker let us all know (I'm interested) NT. posted by Dwin on January 22, 2002 at 14:48:29:
Dwin,
Aluminum 80's are alway a good choice, aspecially if you plan to do shallower dives ot to wear a wet suit. Anything smaller than 80's is a waste of aluminum. If you are going to buy used, buy some that are farely new. Aluminum tanks have fitigue problems, aspecially if they have been repeatably hot filled. They also oxidize around the neck o-ring.
Then we have two steel choices, LP 95's and LP 104's. Other things such as galvanization v.s. paint are also important in long term life of your cylinders.
The manifold is critical. The manifold must be DIN capable. It must also have two post for two regulators. This is where the true redundancy comes from and without two post you might as well get a single tank. On deeper dives (70' and beyond)or overhead environments such as wrecks your gas supply is important. Yokes 1st stages can cock if hit and the o-ring can protrude. It is difficult to reinstall the o-rings on tanks worn on the back.
The center section of the manifold is also critical. Isolators are your only choice to shut down you right cylinder if the right post knob gets stuck in the on position or the knob breaks away. Barreled o-rings on the center sections most outer part like thoughs on Dive Rite, Scuba Pro, Halcyon, SeaElite, allow the center section to rotate if hit hard. This is a good thing. Manifolds such as Sherwood, OMS, ect, have captured o-rings and they don't rotate. If hit hard enough they can bend or even break the isolator knob off, allowing all the gas to leak out.
Don't waist money of mild steel bands. They rust and they break. Buy good bands with lots of surface area to grip the tanks. OMS make decent bands but Highland Mills make the best. They are both Stainless Steel.
I don't mind sharing this type of stuff on the interent but it is easier to shared one on one. It also allows time to become more detailed. Besides, unlike most of you playing on the computer when ever you boss turns their backs, I've have a blue colar job .
JW