Which brand of steel cylinder / tank should I buy?

[Thomas Ivey]

Originally posted by jobowker
I think 7 pages ago, the original question was 'what brand of steel tank'. There were one or two responses mentioning this, but I didn't see the answer to the differences in buoyancy characteristics in Faber vs. PST.

Here it is...
PST LP-95 VS FABER 15 LTR


PST
2640 PSI
Cu.In. 940
Cu.ft. 96.50
Weight 41.0 lbs
Bouyancy/Salt -2.3

Faber
2640 PSI
Cu.In. 915
Cu.Ft. 93.93
Weight 37.2 lbs
Bouyancy/Salt +1.69

data is for tank only.

ti

 

[Warhammer]

Originally posted by Thomas Ivey

This other tank come from Japan and is heavier, longer, and bigger in diameter, is not hot dipped galvanized. Plus it is a made from tubing which is not the preferred way to make a scuba tank.

ti
[/B]

This tank from Japan that you are speaking of wouldn't happen to be ASAHI Steel tanks, would it? And why is tubing a no no for scuba cylinders?

 

[Thomas Ivey]

Originally posted by Warhammer

Originally posted by Thomas Ivey

This other tank come from Japan and is heavier, longer, and bigger in diameter, is not hot dipped galvanized. Plus it is a made from tubing which is not the preferred way to make a scuba tank.

ti

This tank from Japan that you are speaking of wouldn't happen to be ASAHI Steel tanks, would it? And why is tubing a no no for scuba cylinders? [/B]

Yes, it is Asahi. The reason it is not the preferred design is due to the method in closing the bottom of the tank. A tank made from tubing, the starting material look like a big drinking straw. Then one end is thermically closed. This area, which is in the bottom of the tank, can develop cracks. Since cracks are prevalent in spun bottom cylinders the wall thickness in the bottom of the tank is increased, making the tank very bottom heavy.

With this type of design and the nature of moisture collecting in the bottom portion of a scuba tank, these tanks are prone to fail a visual test and concerns of the combination of localized cracking in a area where moisture is collected is the reason for my statement.

This why all PST scuba product is made from a deep drawn process, where the starting material is a solid piece of steel.

ti

 

[scubakat]

Hi Thomas!
I just went to my LDS to purchase a pair of PST-LP-80's & I was told that they have been discontinued. Is this true?

-kate

 

[Warhammer]

Thanks again for the explanation. Did asahi, at one time, use the "Hot Dip Galvanizing" method? Reason that I ask is that I've read somewhere before that they did, but my local dive store was telling me the other day that they had some new Asahi HP120s in and they were painted. So I assume they now use the powder coating like Faber.

 

[Thomas Ivey]

Originally posted by Warhammer
Thanks again for the explanation. Did asahi, at one time, use the "Hot Dip Galvanizing" method? Reason that I ask is that I've read somewhere before that they did, but my local dive store was telling me the other day that they had some new Asahi HP120s in and they were painted. So I assume they now use the powder coating like Faber.

It is my understanding that PST is the only company that has ever hot dipped galvanized a scuba tank. The Asahi tank has been in the market place since 1998, and they have always been painted.

ti

 

[Warhammer]

Ok, thanks Thomas, I'd heard you say before the PST *is* the only one the uses HDG, but wasn't sure that had always been the case. I read that about Asahi in a couple of threads the other day on Rodale's board, while researching the Asahi tanks. Guess the poster just got his info mixed up.

 

[devjr]

OK, Thomas, I believe the tank I saw was an AquaAire manufactured by PST. It was not marked PST which caused the question. Also, as I said, the shoulder and neck looked a bit different from the original Genesis PST 100's that I had seen. Come to think of it, it had a sticker saying something to the effect that PST would not honor replacement warrantee unless the hydro was performed to specific criteria contained in some bulletin. What is that all about?

>>If it is stamped with DOT E-9791 it must be a PST product. In 1986 we sold exclusively to
Sherwood and then later to other companies, then from 1996 to the end of 1999 to
Aqualung/S Divers.

This is another 3500 psi that comes from Japan. It is not hot dipped galvanized, is
heavier, and bigger in diameter. The tank is made out of tubing, which we consider a no
for scuba tanks. The bottoms are real thick, and sometimes they will leak out of the
bottom.

Manufactures can use there name (PST) or will use a M# (MXXXX) only two formats
allowed. The IA/81 is the third party DOT inspector that checks our product.<<

 

[greg somers]

I have just gone through the whole thread and... wow !

How did it get sooo heated so quickly and for sooo long?
I am a strongly opinionated person myself, but I try not to let it get personal. Maybe it's easier to be harsher when you're talking on a thread than in person, but we belong to this thread people because we have a common love for scuba and we ALL want to be better, safer and more knowledgable.

The way that many of the opinions were expressed here was disappointing. I don't believe that any of you are idiots. We all receive different training from different global locales and we tend to reflect that training in our opinions that we share. Please keep this in mind with disagreements in future and consider how a newbie to the threads would feel about this board if they thought that they would get lambasted everytime they expressed an opinion. We want to encourage,not tear down.

As to the original question, I can't answer it because in New Zealand we don't dive with pony bottles.I have never seen a diver use one in 16 years. All pony equipment has to be imported from the US,where pony diving is taught and encouraged by many. It doesn't seem to be warranted in my country and the training reflects that.

Maybe our diving is less demanding here. On a note about dive deaths,all the latest deaths that have been recorded in our country would not have been avoided with a pony system as other factors were involved, (ie 2 divers went into a wreck without a safetyline and got lost inside... wait,that wasn't here,it was in Vanuatu... 3 divers got dragged down deep by currents when they went diving outside of slacktide. They were training as OW divers and the circumstances were uncovered in a trial and the instructor and dive shop were at fault and prosecuted.)

Let's remember that we all have our opinions and we have been diving with those beliefs for years.I'd be willing to dive with most of you, ponied or not, and I think that we are all a great bunch of people from varied places brought together by a love of diving. AMEN.

The one and only Gaspreacher.

 

[Thomas Ivey]

Originally posted by devjr
OK, Thomas, I believe the tank I saw was an AquaAire manufactured by PST. It was not marked PST which caused the question. Also, as I said, the shoulder and neck looked a bit different from the original Genesis PST 100's that I had seen. Come to think of it, it had a sticker saying something to the effect that PST would not honor replacement warrantee unless the hydro was performed to specific criteria contained in some bulletin. What is that all about?

>>If it is stamped with DOT E-9791 it must be a PST product. In 1986 we sold exclusively to
Sherwood and then later to other companies, then from 1996 to the end of 1999 to
Aqualung/S Divers.

This is another 3500 psi that comes from Japan. It is not hot dipped galvanized, is
heavier, and bigger in diameter. The tank is made out of tubing, which we consider a no
for scuba tanks. The bottoms are real thick, and sometimes they will leak out of the
bottom.

Manufactures can use there name (PST) or will use a M# (MXXXX) only two formats
allowed. The IA/81 is the third party DOT inspector that checks our product.<<

Any AquaAire cylinder that fails hydro, PST should be notified so the tank can be evaluated. Since 1902 PST, has always stood behind the products we make. There are two supplemental Technical bulletins that pertain to our products. They can be retrieved from our web site http://www.pstscuba.com

If it is a scuba tank manufactured by Pressed Steel Tank Co. it will have “PST” permanently stamped into the shoulder.

ti