Dive tank permanent expiration?

[elmer fudd]

These shops what won't fill a tank made before 1990 because they're scared of old tanks...next year will the cut off be 1991? Then the following year 1992? Etc?

I bet you a doughnut that its been '1990' for years.

It becomes not about age of the tank, but some misinformed nonsense about the old alloy tanks. Politely inform and attempt to educate (documents in hand). If that fails, just move along.

I think the idea was just to make a simple rule of thumb for how to avoid 6351 alloy. I wouldn't be surprised if there wasn't a bit of employee liability avoidance going on as well.

 

[Superlyte27]

It's interesting to consider the cost issue from different sides. As a consumer, I see shops making a decision that retires tanks prematurely without cause. While the profit to the shop/tank may be small, the cost to the consumer is massive. It equals all tanks pre 1990 (if that's the cutoff) multiplied by the cost of those tanks at retail prices. That's a big number so I guess a discussion related to it's necessity is valid.

Ultimately I do believe the guy with the compressor gets to make the decision but let's not pretend there isn't a substantual cost attached to it.

Someone show me one piece of evidence that my 1989 Catalina Al 80 (that has passed hydro and vis) poses a threat that suggests it not be filled.

Risk is also an interesting comparison. I wonder how many shops that refuse to fill also promote rapid cert. courses or learning to dive without even knowing how to swim? How many new divers die during training/year compared to fillers from exploding Al tanks. That would be an interesting ratio to visualize and an equally interesting discussion regarding profit motive.

I can't show you that evidence, as Catalina never used the bad alloy.

---------- Post added July 19th, 2013 at 08:12 AM ----------

I don't know captain... most of the hydro facilities I have used, pride themselves on following the written procedures for each tank. I have picked up my 72s with 3600 in them way too often and that's after they had cooled down. Twice I have picked them up with over 4,000 psi. You can't exceed rated pressure with impunity. The shop isn't doing me any favors with such a hot fill.

I'm not afraid of much, but I would be terrified of a steel 72 with 3600 or 4000psi in it.

---------- Post added July 19th, 2013 at 08:17 AM ----------

I think the idea was just to make a simple rule of thumb for how to avoid 6351 alloy. I wouldn't be surprised if there wasn't a bit of employee liability avoidance going on as well.

I can guarantee you that's why we do it. We found no matter what employee we hired, we can't get them to check the chart to see if the tank is on the list. And frankly the list also states that tank X, Y, or Z might be of the bad alloy. So, we simply engaged the blanket policy on the tanks. And as I said before, we're okay with it.

 

[captain]

An example of a hydro shop that probably did not follow the round out procedure and failed two good tanks.

Vintage Double Hose ? View topic - Pig-In-A-Poke OR Maybe a Bargain

 

[chrpai]

I'm not afraid of much, but I would be terrified of a steel 72 with 3600 or 4000psi in it.

That's interesting considering your (very funny) comments about LP steel tanks having their turn pressures right on the crown.

 

[Superlyte27]

That's interesting considering your (very funny) comments about LP steel tanks having their turn pressures right on the crown.

Steel 72's are a different animal than LP85's 95's 104's and 121's. Cut any of those tanks in half and compare them to a 72, you'll see the difference.

I said something "very funny"? Did people laugh? I don't remember it. It's so rare that I say anything even mildly funny.

 

[chrpai]

Sorry, my bad. WeDiveBC actually wrote it, you just provided the smiley face. I was too busy laughing to get it right...

That's why they stamp the turn pressure on the side of the tank

 

[Superlyte27]

Sorry, my bad. WeDiveBC actually wrote it, you just provided the smiley face. I was too busy laughing to get it right...

I remember the post. I was going to comment, but then couldn't come up with the proper words. Ultimately, his post wasn't quite accurate. As tanks will show 2400 or 2640 which really isn't my turn pressure.

If my starting pressure is 4000psi, my turn is actually 2700

---------- Post added July 19th, 2013 at 11:56 AM ----------

But, truth be told, I prefer CCR to OC. And I don't got no stinkin turn pressure

 

[captain]

Steel 72's are a different animal than LP85's 95's 104's and 121's. Cut any of those tanks in half and compare them to a 72, you'll see the difference.

I said something "very funny"? Did people laugh? I don't remember it. It's so rare that I say anything even mildly funny.[/QUOTE

If they are all built to 3AA specification you can't make a comparison on strength on what the wall thickness is. The larger the diameter of the tank the thicker the walls have to be to contain the same pressure. A tank 3 feet in diameter might have a wall thickness it 2 inches. That is no indication that the wall thickness on a 72 is not thick enough. It's called mechanical engineering.

 

[corvettejoe]

After reading all the comments on getting tanks hydroed directly from the facilities that do it.. I think I know where I'm going next time I didn't know this was do-able
We have quite a few facilities in my area.

Of course I was just made aware I would still need to get a VIP when the testing was done... so... meh.

 

[chrpai]

I remember the post. I was going to comment, but then couldn't come up with the proper words.

Good thing you didn't. That level of nitpicking would have ruined the joke.