VIP on AL cylinders = stupid $$$ game

[Crazy Fingers]

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.

 

[oly5050user]

removing valve,replacing o rings, completing visual ,completing eddy test all insures that the tank is safe..Poor compressor maintance,stress cracks,prevents tank bonding to valve..see examples of tanks that have water in them and rusted so bad(steel tanks)that the valve became clogged and no air went through it.Happened in cozuumel..I have a alum tank in the store that had about 2 cups of water in it..totally pitted and the valve was a real pain in the *** to get off..failed it of course..vip had not been done in over a year and the user filled it off their own compressor.

 

[Crazy Fingers]

removing valve,replacing o rings, completing visual ,completing eddy test all insures that the tank is safe..Poor compressor maintance,stress cracks,prevents tank bonding to valve..see examples of tanks that have water in them and rusted so bad(steel tanks)that the valve became clogged and no air went through it.Happened in cozuumel..I have a alum tank in the store that had about 2 cups of water in it..totally pitted and the valve was a real pain in the *** to get off..failed it of course..vip had not been done in over a year and the user filled it off their own compressor.

Okay, it may "assure the tank is safe" (unless you want to talk about thread wear which, if no one caught it, might get to the point that bad things happen) but the question is whether or not it is necessary for aluminum tanks at all.

Your example of steel tanks is not what we are talking about. I agree that visual inspection of steel SCUBA tanks is prudent.

As for the valve being a real pain to get off, shouldn't the Compound 111 put on the threads when the valve was installed help with this? And is this not evidence that removing the valve all the time for a visual inspection of dubious usefulness is simply wearing out the neck threads? Is the use of penetrating agents to remove the stuck valve merely an excuse to charge for cleaning to remove said penetrating agent? ... in other words, if we make them get a VIP every year we can get $15 for VIP and then another $30 for cleaning to remove the penetrating agent we had to use to do the VIP!

As for the example of a user filling a tank with his own compressor and getting lots of water, I guess it's possible if the user didn't have a moisture trap or didn't maintain his compressor? But keep in mind that there are thousands and thousands of STEEL breathing air cylinders which have been in service for decades and get nothing but a hydrostat every 5 to 10 years. These cylinders surely have been filled by countless different compressors, and I haven't heard of any of them catastrophically failing... DOT seems to agree.

 

[TSandM]

My LDS has a vivid photograph of an aluminum tank that failed when they filled it. A crack in the neck of the tank, which should have been picked up when the tank was inspected, progressed and eventually failed, allowing the shoulder of the tank to blow off. I've seen them going over an Al tank with the device they use to find cracks. It detects things you can't see until the machine calls your attention to them.

 

[WesTexDiver]

You are correct, AL does not rust, but it does corrode. refer to the link for the many ways that it can. http://www.snelsons.co.uk/aluminium_corrosion.html I fill tanks every day, and do not want to become a statistic. My family even enjoys when I make it home safely, not sure I have a price that I could put on that.

 

[Nemrod]

Here we go again as a former President would say, the alumiunm tanks which had only three verifible failures were made from the 6135 alloy. Luxfer and Catalina quit using this alloy and went to 6061 alloy. Only the older aluminum tanks have had failures and only the older aluminum tanks require eddy current inspection to look for cracks in the neck area. Some of the tanks that failed were suspected of having been abused. Go to the Luxfer website and read the findings.

Aluminum tanks currently in production DO NOT GET an Eddy Current Inspection--it is not required and is not needed.

As to yearly inspections, they are probably not needed--make your own VIP stickers and inspect the tanks yourself, I do. N

edit to correct typos

 

[spankey]

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

 

[Dive-aholic]

Aluminum tanks currently in production DO NOT GET an Eddy Current Inspection--it is not required and is not needed.

As to yearly inspections, they are probably not needed--make your own VIP stickers and inspect the tanks yourself, I do. N

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.

I also agree that inspections can be done at home. I do mine, but I also went to the trouble of getting the training for it. It's not just about peaking in the tank. It's examining the outside, the inside, measuring any abnormalities, checking the threads (which I think is done much more thoroughly by a good tech than by a piece of equipment), documenting all findings, etc. BTW, I've heard of tanks that have passed an Eddy Current, but failed a manual visual inspection for a neck crack! It's not rocket science, but when it comes down to it, I want the legal protection if needed.

As for annual inspection - I sometimes get my tanks filled at shops when I'm away from home. I don't know what their compressor looks like, how it's maintained, etc. This is why I visual my tanks every year. I've seen and heard of tanks with water and corrosion inside because of bad maintainence. I hope I've chosen reputable shops, but I don't always know for sure.

stop being soooo cheap its only $25 max. Learn to support the industry.

$25 x 26 tanks is $650 a year. I'll do my own, thanks.

 

[Nemrod]

Twenty five dollars, holy cow, that is a bit steep. I would not pay that much.

When aluminum is exposed to air/moisture and other agents a layer or film of aluminum oxide forms. This layer is very resistent to further corrosion. If it is scratched through it will reform. However, serious exposure to corrosive elements of an interior space such as the interior of a tank should be inspected regulary if you suspect salt water incursion. Aluminum tanks probably really don't need a yearly VIP. Aluminum cannot rust BTW, that is a ferrous process only.

Steel, being ferrous, will rust and unlike aluminum does not form a self protecting layer of oxide. It will continue to rust until it perforates--given time. Most steel tanks today have a stabilized interior surface, it has been passivated I think is the term to help reduce rusting. Flash rust will occur when clean steel is exposed to moisture. It generally does not immediantly progress to a pitting type process and is fairly normal condition. There are agents that can be introduced after tumbling to reduce rusting.

Steel tanks can be PITA and probably do need yearly inspections to reduce the likelyhood of serious rusting.


""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.""

That is why both Luxfer and Catalina put a huge decal on the tanks clearly stating their tanks are not subject to and do not require eddy current testing and I would refuse to pay for that foolishnes. If they want to do it for free, go ahead.

"As for annual inspection - I sometimes get my tanks filled at shops when I'm away from home. I don't know what their compressor looks like, how it's maintained, etc. This is why I visual my tanks every year. I've seen and heard of tanks with water and corrosion inside because of bad maintainence. I hope I've chosen reputable shops, but I don't always know for sure."

Yes, yes, of course, that can be a huge concern. N

 

[SeaLevelScuba]

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.