Filling scuba tanks

[Schwob]

I surely used the wrong word, danger, when I expressed my feelings there. I should have said, a destruction of a trip, or a situation that ruined the planned dive. Believe me it has happened to us. And yes, you are right; we would never take that attitude and try to conserve air. We both know what we need to do what we want to do; and that is the point Im saying that a short fill can ruin a day, weekend or even more.

I can agree with that.
But I check my fills on site at pickup and ask for a top off if it was done some time ago and the tank feels cool and pressure is low ...or if it just was done 10 minutes ago, pressure is nominal, but the tank feels quite warm. The latter may be the harder ask, but checking and asking so far works for me. Worst answer I ever got was somethin along the lines of: "can't overfill, shop rile, but if you can wait an hour or even half, we'll top it off".
And of course I learned that not checking and trusting just does not work, not even at the good shop.

 

[seeker242]

This tells me the author of that article had their own agenda and were not totally objective; typical of the paranoia the certifying agencies so love to preach. The total emphasis is on "protecting your a*s"; with no regard to damage you cause to other people's property.

PSI is not a "certifying agency preaching" like you describe. Tank manufacturer Lufxer recommends PSI certified technicians in order to maintain proper saftey. They would not do that if PSI was advocating unsafe practices.

 

[tursiops]

PSI is not a "certifying agency preaching" like you describe. Tank manufacturer Lufxer recommends PSI certified technicians in order to maintain proper saftey. They would not do that if PSI was advocating unsafe practices.

The OP was just showing his confirmation bias. He didn't really want to know what others thought about wet fills, he just wanted people to agree with him.

 

[papaouiee]

The OP was just showing his confirmation bias. He didn't really want to know what others thought about wet fills, he just wanted people to agree with him.

I'm only speaking on what I was taught and have had confirmed all my life. It's not a bias opinion, but listening to those defending the dry fills; their answers come from lack of knowledge of physics, the way to fill a tank (water and electricity don't mix and if a tank explodes in water it creates a bigger explosion) and the protect me and the hell with your gear attitude.

Any manufacturers out there who can give us some insight; it seems the manufacturers are saying one thing and the certifying agencies are saying another. Again, Pressed Steel Tanks' head engineer told me a few years ago that not filling them slowly in water damages them over time. Seems the people that make these tanks know a little more about them than certifying agencies. When I joined this site, it was mentioned that manufacturers monitor this site.

The other possibility is that when I talked to Pressed Steel Tanks, we were talking about steel tanks; most people dive with aluminum; is it possible that protocol is different for aluminum than steel. Seeing how hot tanks get from the dry hot fills I see them do around here, only tells me it's bad for the tanks since heating metal up like that over time weakens the metals strength; that is just basic metal science 101.

 

[The Chairman]

1.) leaves you at the dive site short up to 500 lbs of air

Only if rushed.

2.) destroys the life of tanks

This is a myth.

3.) is out right dangerous.

This is paranoia and trying to justify how they do it. Dive and let dive.

There's a lot of bogus crap, er knowledge when it comes to filling tanks. Shops often blow the 'dangers' way, way, way out of proportion in order to demonstrate to those who don't know any better, just how superior they are. Tanks are destroyed by common neglect more than anything.

 

[boulderjohn]

There's a lot of bogus crap, er knowledge when it comes to filling tanks. Shops often blow the 'dangers' way, way, way out of proportion in order to demonstrate to those who don't know any better, just how superior they are.

If you rely on a shop telling you what's what with tank rules, compare these experiences I have had.

1. A shop I used to use for fills (not technical) would regularly fill AL 80s so that they finished with about 3300 PSI--10% over their rated pressure. (They were not the AL 80s with a 3300 rating.) The manager and most of the employees, however, would not fill my steel LP 85s to their rated pressure (2640), saying it was too dangerous to do so. I had to argue to get them to fill them to 2500. Ironically, when I dived there with friends who rented AL 80s, they had more gas in those AL 80s than I had in my LP 85s.

2. Because of that, I switched to another shop just a few miles away for my fills. Their stated policy was that they would fill LP tanks like mine to 3000 PSI, but that was usually not what happened. In order to give me the nitrox percentage I wanted while topping off whatever was left from my last dive (using their banked gases), they would often fill those tanks to about 3400 PSI.

3. Taking those same tanks into any typical cave country dive shop will get them filled to 3800 PSI.

 

[The Chairman]

If you rely on a shop telling you what's what with tank rules, compare these experiences I have had.

I hope I'm not out of line here, but %50 of what some shops tell you is all about selling that shop as 'the best". It's not always obvious and it's often downright deceptive. It's the tired "If I don't sell, teach, or dive it, then "it" must be crap!" mantra. These are the shops who don't like the internet because we expose their crap for what it is.

 

[Rred]

Wait, so you guys are refilling used tanks, instead of buying factory-fresh new ones that come prefilled with guaranteed clean factory air for each dive?

Isn't that, you know, like washing dirty dishes and re-using them, instead of having a fresh new set for each meal?

Ugh.

 

[Akimbo]

Almost everyone I know (but not everyone) believes that a water bath does little to nothing of value when filling a tank.

(caution, geezer sea story)
That depends on the water bath. The first dive shop I went to was in a side yard shed next to the owner's house, who ran his plumbing company by day. He built the most amazing fill system that circulated about 50 gallons/minute between the stainless steel tank he fabricated and an evaporative cooling tower. It didn't matter how fast he jammed my tanks, they were still cool to the touch by the time I got home.

 

[BRT]

(caution, geezer sea story)
That depends on the water bath. The first dive shop I went to was in a side yard shed next to the owner's house, who ran his plumbing company by day. He built the most amazing fill system that circulated about 50 gallons/minute between the stainless steel tank he fabricated and an evaporative cooling tower. It didn't matter how fast he jammed my tanks, they were still cool to the touch by the time I got home.

My testing has shown that a water bath really helps on pressure drop later. That said, I don't bother and just fill to 3900 so they settle at about 3600.