VIP on AL cylinders = stupid $$$ game

[Crazy Fingers]

Unfortunately until cylinders are made of some clear aluminum (as of 2006 it doesnt exists) where the folks interacting with the cylinder can see inside it, a visual a year is the only way to see if moisture traps are working or not. Having the opportunity to inspect 500+ bottles a year where the vast majority turn out fine, the conditions found in some may astound some of you, from dip tubes loose in the bottom to about an inch thick of aluminum oxide mud to several cup fulls of water. There is currently a bottle sitting in the shop right now that is just over a year old, that had a large amount of aluminum oxide mud in the bottle of it, after cleaning it several deep pits were identified, this was discovered on the first annual vip for the cylinder, imagine it that was left unattended for 5 years, imagine how that air must've tasted.

What about the possibility of analyzing the air inside for moisture content with a simple moisture analyzer? Maybe take the tank down to ~250 psi and measure? If the tank is full of water the moisture content should be whatever the saturation concentration is at the tanks pressure. A correlation surely could be developed. This way you wouldn't have to devalve all the time.

 

[photohikedive]

I completely agree. However, I've seen quite a few shops require an Eddy Current on all AL tanks just because they can charge more for it. The average price I've seen is $12-15 just for the Eddy test! Granted, the equipment costs quite bit, but at what they're charging, they're making their money back pretty quickly.

heck, when I moved to FL, two out of the three tanks I had were deemed "too dangerous to fill" and I was told that no one would fill them. not because they had any signs of damage, or failed inspection, but because they were the older tanks. the shop owner took the valve off, and damaged the neck so it couldn't be filled.

 

[Rick Murchison]

... the question is whether or not it is necessary for aluminum tanks at all ...

According to Luxfer, the stress problems can be adequately tracked with the five year hydro cycle, so only if there's a problem with what's been put in the tank.
Just clean breathing mixes or air? - nope... don't need it.
A little water or oil or carbon from a malfunctioning compressor or bad filter - yep, definitely need it.
And since the best way to see if there's anything bad in the tank is to have a look, that's what I do. At least once a year - more often if I'm suspicious.
And then there's the five year old o-ring thing too. Sometimes they make it that long, sometimes they don't. I like to replace mine about once a year.
Rick

 

[rigdiver]

Since I love to rile you people up, I'm gonna throw you something else to chew on. Me and one of my local gas suppliers had a discussion about this earlier today and came to agreement.

Yearly visual inspection of modern aluminum cylinders is stupid, and yet another dive industry scam to make money. In an aluminum cylinder which does not oxidize beyond a monolayer, "rust" isn't really a concern. I think it's left over from the days when every tank was steel and interior rust could theoretically cause corrosion from the inside and failure of the cylinder. Once the industry moved over (mostly) to aluminum tanks, why stop the requirement if it gets you $15-20 per tank per year?

But the conspiracy gets worse... valving and devalving an aluminum cylinder only puts needless wear and tear on the threads, which might cause it to fail inspection, or worse. The process therefore costs a diver more money, wears his cylinders out faster, and is quite possibly more unsafe than simply hydrostating every 5 years and having no visual.

Tell that to the people that have been seriously hurt, or the family of one that got killed.

 

[cummings66]

Since I love to rile you people up, I'm gonna throw you something else to chew on.

If this is your only purpose on scubaboard you need to be booted.

However, if you desire to learn why you're wrong then look no further than your local airport. Pilots fly planes, made of what? Now, one of the biggest worries we face is corrosion and it certainly does not stop at the surface as you seem to believe. It will corrode all the way through in a non salt environment. There are many names for the types of corrosion that happens to aluminum.

You believe the VIP is a crock, yet you discount all the reasons it's important. You don't know the state of the compressor, I've seen many tanks that you could place a white cloth over the valve and open it and stain the cloth. Do you ever do that?

I've seen places give water in the air, in fact one of my tanks got water in it that way and it was discovered at the testing you so believe is not necessary.

You are so wrong in so many ways about your beliefs that I'd suggest you take an intro to scuba course and pay attention this time.

I will agree the prices seem high in some areas however, but theVIP is a necessary thing.

 

[Guba]

Okay, I'll throw in my two cents worth...first, the story.
While on a dive in Playa del Carmen, I rolled (inverted head down) to take a picture of a turtle. About a breath after righting myself, it became apparent that something was wrong...very wrong. At BEST, I was getting about 25 percent air delivery. That meant that I couldn't exert myself at all and I had to draw my breaths veeeeeeery slowly to get enough to survive. Swimming upcurrent to my buddy (only 10-15 feet) wasn't a possibility, and I didn't relish the thought of ascending 65 feet in a controlled emergency ascent. Instead, I dropped to the divemaster who just happened to be 10 feet below me. We made a slow ascent with no further incident. When I removed my first stage, imagine my surprise (and that of the dive operators) to see it totally plugged with a white, powdery residue--aluminum corrosion! Not only was the tank fowled, the tubelike "snorkle" on the valve stem was completely gone, allowing the debris to roll around and clog my first stage.
So I dispute the idea that aluminum doesn't corrode (I'm also a chemist), and this points out that vis inspections are to do more than just check for it. They also catch other problems with the valves and other equipment.
It appears that guidelines in Mexico are either lacking or are not enforced like they are here. When it comes to a paltry 20 or 25 bucks for a vis inspection, I'll pay it. That amount seems like only pennies when you're at depth and can't get sufficient air, trust me!

 

[mike_s]

heck, when I moved to FL, two out of the three tanks I had were deemed "too dangerous to fill" and I was told that no one would fill them. not because they had any signs of damage, or failed inspection, but because they were the older tanks. the shop owner took the valve off, and damaged the neck so it couldn't be filled.

I've notice that a lot of the shops in Florida won't fill the 6351 tanks. But shops elsewhere will. I think that part of that is because of all the "transient tanks" coming down on vacation and they don't know who visual'd them.

He damanged your tank because he made the determination not to fill it? that's absurd. DOT just published a bulletion on now to inspect older 6351 tanks. They are perfectly safe as long as they are inspected properly.

Did he damage the tank w/o your knowledge? I'd be pissed if they did that to mine. What was the name of the shop Fred?

 

[PhilEllis]

Since I love to rile you people up, I'm gonna throw you something else to chew on. Me and one of my local gas suppliers had a discussion about this earlier today and came to agreement.

Yearly visual inspection of modern aluminum cylinders is stupid, and yet another dive industry scam to make money. In an aluminum cylinder which does not oxidize beyond a monolayer, "rust" isn't really a concern. I think it's left over from the days when every tank was steel and interior rust could theoretically cause corrosion from the inside and failure of the cylinder. Once the industry moved over (mostly) to aluminum tanks, why stop the requirement if it gets you $15-20 per tank per year?

But the conspiracy gets worse... valving and devalving an aluminum cylinder only puts needless wear and tear on the threads, which might cause it to fail inspection, or worse. The process therefore costs a diver more money, wears his cylinders out faster, and is quite possibly more unsafe than simply hydrostating every 5 years and having no visual.

You and your local gas supplier had a discussion and came to an agreement. Unfortunately, you guys must have been using some bad assumptions to begin with, because you and your local gas supplier reached an "agreement" that flys in the face of common sense.

First, don't assume that EVERYTHING that goes on in this business is just a "scam" to get money out of your pocket. Trust me, if I was devising a "scam" to get money out of your pocket, it would target something a little bigger than a ten spot. lol. While the interior of your cylinders is ALWAYS SPOTLESS AND TROUBLE FREE, don't assume that is the case for everyone. The internal appearance of a dive cylinder, filled maybe 30-50 times during a year, is much more revealing of troubles than you might assume.

Second, the claim that removing the valve once a year (15 times over the normal expected life of an aluminum cylinder) creates more damage than is detected during annual visual inspection, is well.........fools engineering logic. The threads in an aluminum cylinder can withstand thousands and thousands of insert and removal cycles from the valve.

Third, why is it ok for YOU to assume that anything I do for a profit is a scam, yet what YOU do for a living is perfectly just and beneficial to society? Remember, the viewpoint of the Thanksgiving turkey is totally dependent on which side of the table you are on. Anyway, thanks for your comments and generation of interesting topics for discussion.

Phil "tank fill monkey" Ellis

 

[captain]

stop being soooo cheap its only $25 max. Learn to support the industry. I wish divers were more like golfers

I have 7 tanks, I'd rather have the $175 for gas for my boat than in a LDS's pocket for something I can do myself.

 

[fire_diver]

stop being soooo cheap its only $25 max. Learn to support the industry. I wish divers were more like golfers

Maybe you should quit being cheap and actually buy your own tanks. At $25 a pop, I could buy a new tank ever year for the cost of all my visuals.

FD