need some advice please

[standingup]

When last I used double hose it was with steel 72's @ 2000 lbs---- Now with these dang new al 80 @ 3000- do I need to bleed them down to 2000 to use my rebuilt double hose aqua master-- or will the regulator take the 3000 lbs
thanks for your thoughts

[captain]

U S Navy used them at 3000 psi, not a problem

[YankDownUnder]

The working pressure stamped on my 1954 Broxton triples is 2600 psi, so apparently high presurre is not a new thing. 3000 psi aluminum 72s were being sold by US Divers concurrently with the last of the Aqua Masters. The tanks were lousy, but the regulator worked fine.

The US Navy non-mag 90s were 3000 psi working pressure tanks and the regulator was basically an Aqua Master with a normal yoke and a different paint job. (I have one in new condition and the yoke appears like any other.) Again, the tanks were lousy, but I had no trouble using an Aqua Master on mine.

Now I have a Royal Aqua Master, which has a long yoke and I use it on Faber 3400 psi (232 bar) tanks with no problems so far.

[standingup]

did they change the al 80 after the 1980's if not why did they catch on, over the steel

[captain]

The aluminum 72 had bad bouyancy characteristics. Aluminum was being advertized as rust free with no need for internal inspections, that didn't last too long

[JES]

did they change the al 80 after the 1980's if not why did they catch on, over the steel

IMHO there are three major reasons that aluminum 80's caught on;

1) Price
2) Price
3) And Finally Price

The difference in the cost of a steel tank compared to the cost of an aluminum tank is very large. A steel 80 tank can set you back $300.00 while an aluminum 80 can be purchased for about $120.00.

I firmly believe that steel is by far the better choice. However, for the majority of divers it is hard to justify the price difference.

[1969ivan1]

JES is right as usual.

[treasureman]

I buyt used steel 72 , hydro and vip foir under 120 cdn which is a steal pardon the pun. I strip em and galvilite them and dive em til they turn blue. Steel is the way to go and steel 72 can be had cheap

[Nemrod]

Thing is, back in the day, steel 72s did not cost very much and I don't remeber them being any more than an aluminum 80 or actually less. The overlap in time between when steel 72s went away and modern type aluminum 80s came on the scene was small however. I think it is because steel tanks rust up in sea water and a spate of incidents with the plastic lined tanks that haunts us to this day. I don't think it was cost. Does anyone have a price list from back then?

James

[YankDownUnder]

I have a friend who runs the scuba repair shop which local dives shops turn to. He has been in the business for 20 years now. He tests fire department scba tanks, and the equipment used on ships. I spoke to the employee who actually tests the tanks. His name is Ross. He has spent most of his working day for the last 4 years testing tanks. He said he does not remember failing a steel 72 and they are tested annually here in Australia.

Aluminum tanks can suffer sustained load cracking and seem to fail more often he said. If steels are used with high oxygen content and get moisture in them, they can rust rather quickly. If the rust is caught in time, it can be stopped by tumbling or brushing. Most tanks will test okay unless there has been neglect ie. moisture inside according to the owner.

The only prices I have are in my collection of local diving magazines and books from the 50s. In 1955 most rigs were sold complete with regulator and harness. A USD single was $160, a twin was $260, and Navy triples sold for $295. (Ref. DIVE, Carrier first edition, 1955. Aluminums did not hit the market for another 10 to 15 years I believe. I bought my first aluminum 72s in 1971.

[dhaas]

Amigos,

Aluminums have failed very minimally considering the bazillions being used out there every day. A gang of Luxfer tanks is the only known neck thrread cracking scenario, and this is so minimal s to be not even considered.

They DO have some buoyanncy differences you have to adjust for, but not a big deal.

AS JES states price, plus the fact that dive resorts / ops using them year after year in salt water gained a maintenance advantage over steel.

I have 3 aluminum 80s (one over 20 years old) plus two low PSI steel 72s for vintage gear (I have an old Mistral with skinny yoke and a Conshelf VI).

Each for a specific purpose....

dhaas

[dhaas]

GEEZ,

We need a way to go back and EDIT our posts, plus I need to double and triple check my spellin' before hitting the "Submit" key

dhaas

[Nemrod]

When did steel 72 go out of production? I think the last one I bought new would have been around 1976. Since I was a poor college student I did not buy the expensive aluminum tanks.

The bad alloy Luxfers are the only incidents of neck cracking and it was minimal. There is a FAQ on the Luxfer page for this that dispells all the myths.

Everyone claims there are all these steel 72s around but in the four years or so I have been looking for them these are the only three unlined--unrusted--in hydro--sreel 72s I have come across. That is why I was and am SO HAPPY. I hope to pick up a couple of more fine specimens of the breed and maybe some steel 38s or such as that as money and good fortune permit.

James

[Bryan]

Rip and I have discussed the edit thing and there is NO easy way to allow everyone the ability to edit posts on this style forum. All members would have to be made moderators with admin ability and that's not going to happen. If I have a long reply to do, I usually do it in word or E-mail and spell and grammar check and then paste it here.....I know it's a pain, just and idea though.

[1969ivan1]

i donnt seee a probleem with speeling erors?