Good stuff as always :) Down here in Australia we have to have the Hydrostatic test done once a year and it's more expensive like $100 which feels like over-kill
Oh wow! Bet your incident of tank failures is very very low. North America is 5 years hydro and 1 year Visual Inspection. Stay safe and cool my friend.
Dear " maestro " if people are teaching any subjects like you do; everyone will be out of the streets and have a good job or at list enjoy a better quality life!!! As Amalfi coast and in general Italian coasts scuba diver of over 55 years ( I am 59, early years in Apnea ) I applaude you and thank you!!! Grazie molte.
Thanks very much for the compliment Armando. I hope you're watching my 'Vintage Scuba' playlist. You certainly qualify! I'm not a 'special' teacher. I just keep it simple, no fancy and unnecessary stuff if I can avoid it. Thanks for watching. Alec
It's not a toy, it is your life and that is what many divers forget/ignore. Many divers take better care of their car hub caps! Thanks for the feedback.
Hi Alec, I just recently started SCUBA diving and I wanted to thank you for your continued effort putting out all these videos with all that valuable information. From what I've gathered so far DIN valve steel tanks are a lot more common in Europe than INT valve aluminum (or INT steel?) tanks. DIN interconnects seem to have the benefit of being able to easily convert to INT with the inexpensive yoke adapter and the added benefit of being able to handle up to 300 bar (~4350 psi) with the appropriately rated tanks. The INT interconnect seems to be able to only handle 200 bar (~2900 psi) operating pressure. I am not sure what the situation is like in Northern America regarding 300 bar fillings of tanks, but I feel that if you are in need of a bit more air, the DIN / 300 bar combination of regulator and tank might be the slightly more flexible but also heavier solution compared to INT / 200 bar. Service intervals for tanks are the same as john b mentioned here in Germany. Maybe because of universal European regulations? I don't know for sure. I'm sure you know all this, I just felt like sharing this information. Anyway, keep the Tech Tips comming. :)
+oBsRVr666 Thanks for your comments. You are quite right. The DIN is needed for higher pressure tanks. That's all. They are NOT better valves nor a better system, a better seal or anything else. The trapped O-ring design of a DIN valve is needed for pressures over 3500psi. So if you're using higher capacity tanks or any tank that is filled to 3500psi or more, you'll be using DIN. If you're using standard 3000psi tanks, the yoke is not only perfect but it's cheaper, just as solid and quicker to mount. Some divers want the increased negative buoyancy of a steel tank but do not want to use DIN so you can now get steel tanks rated to 3442psi. Someone asked why 3442psi. The answer is simple and you now know the answer - DIN is not needed at 3442. 60psi more and a DIN valve is needed with increased cost for both the valve and the regulator. The best comparison is an outboard motor. It's almost impossible to buy a 10 horsepower outboard. You can get 9.5, 9.7 even 9.9, but not 10. Why? At 10 hp, the standards for manufacture of the engine increase substantially and so does the cost. So a 9.9hp motor might cost $900; a 10hp would cost $2000.
+Scuba 2000 You make a good point but: INT system uses 2 O-rings (if the valve is convertible with an DIN/INT adapter - like in this video) DIN system uses only one O-ring INT system is great for dive centers because is easier to mount and there they should have plenty of spare O-rings DIN system is better for personal use, not only because it holds 300 bar but also it's lighter, you have a smaller profile ...
Hi Alec, great video! However, I also have a question regarding steel cylinders. I was curious about the process companies use to prevent rust from forming on steel tanks after they preform a hydrostatic test on the cylinders, do they use chemicals to protect the tank or another method such as filling the tank with some kind of oil instead of water? I hope this question isn't repetitive, I just couldn't find to much on the web about this subject. Thanks.
Here in Sweden alu-cylinders are almost only used for stage/deco tanks. I'd guess it's because of the buoyancy "benefit" of the empty steel tank when diving in cold waters. So aluminum cylinders aren't likely to be seen here in Sweden. Interesting video tho!
Why do people use low pressure tank vs high pressure tanks? I’d love to see a video about it if it’s a long answer? Does the buoyancy characteristic change? Can you hot fill a low pressure tank? Thanks for the great videos🙏🏻
Alec, is it common practice to pull a vacuum on a serviced cylinder? I know in HVAC, you pull a vacuum after you open the system to remove any moisture that might be in there. Seems like it might be adventitious for scuba cylinders as well, since water causes corrosion. Just wondering.
We don't do that. In fact very few high pressure cylinders, even oxygen, are vacuumed. It's hard to do, costly and for scuba, not a big advantage. Our tanks are mainly aluminum and contain 80 cubic feet or more. And the air we use is very dry so generally we simply fill the tank with dry air. The ambient volume of the tank is very small so a couple of fills with dry air and it's dry in there!! Alec
Assuming no abuse or damage, can a tank be filled literally hundreds of times through the years and still be safe so long as it has not gone beyond it's expiration date? I'm just trying to understand what actually contributes to a failed test; pressurization cycles, time, or some combination.
Your tank stretches and shrinks every time you fill it and empty it. It's actually quite measurable. As with any metal, if it is bent back and forth it loses elasticity and becomes brittle. Think about a wire coat hanger which you can break by bending rapidly many times. When a tank becomes brittle, it will not stretch when being filled and will shatter. Granted, it takes thousands of bends (or stretch/shrink cycles) for this to happen but there are so many variables that a 5 years test period of the tanks remaining elasticity is reasonable. So, to answer your question, it is not time, temperature or any other factor other than pressurization cycles - stretch and shrink cycles if you like. Alec
@@AlecPeirceScuba_SeaHunter That's good to know. I use my (aluminum) tank strictly in the back yard swimming pool as I am not a diver. It helps when doing underwater repairs, but also is used occasionally for recreation. It's only been refilled literally a few times over the many years, and I purchased it brand new. However, it has never been hydro-tested. For that matter, I also have a couple CO2 tanks. Same story. All my tanks have never been abused or damaged, nor have they ever come close to having zero pressure (contamination risk). Based on all that, I would presume that they are relatively safe. I know you cannot advise other than what industry standards/law prescribes, nor would I want you to. That said, just curious your opinion of my risk assessment.
Pretty low risk I'd say. You should know that it's best to store tanks with low pressure rather than filled. I know that's a nuisance since you have to go and get them filled to use but storing for long periods under high presure can lead to slightly shorter life. It's not really a big deal but good to know. Perhaps you could live with the scuba tank at say 1500 psi instead of 3000. That will still give you 45 minutes+ in a pool. Take care. Alec
Hi Alec, Firstly I would like to thank you for all amazing information you are providing. I need help, I have 18L tank, how can I know how many CU FT of this tank? I’m not able to fit properly my Eon Core on this tank.
I checked and this is a good comparison from Australia: Using standard Australian Sizes: 10L tank = 80 cu ft tank (when filled to 226.5 bar / 3285 psi) 12L tank = 100 cu ft tank (when filled to 236 bar / 3420 psi) 15L tank = 125 cu ft tank (when filled to 236 bar / 3420 psi) 18L tank = 150 cu ft tank (when filled to 236 bar / 3420 psi) please note these calculations are using Australian conversions where 1 ata = 1 bar = 14.5 psi and 1 cu ft = 28.32 Litres.
Thank you for the great content! For the hydrostatic test, does that also include a visual inspection? Or if your tank has been out of test for a number of years would you require both hydro and visual tests to be undertaken? Cheers.
Well, Ultimate. What can I say? You must have binge-watched my Vintage Scuba videos. I appreciate that and I'm glad you enjoyed them. This is a single answer to all your comments (sorry). I watched your UA-cam video of diving with the US Diver 2 hose. We wouldn't really consider that a vintage regulator you know,. But it's neat all the same. I also saw your speargun collection. I have dozens of them and am slowly selling them off, along with most of the stuff you've seen in my vids. Subscribe to my eBay site and watch it. I list a bunch and then rest for a while so don't give up. Or you can ask me for things that you're looking for. Reach me at seahunter@vintagescuba.com . Take care. Alec
Thanks for your vids, I especially like the vintage equipment ones. My question is about Hydro testing and more specifically over filling. A while back I had my 14 cu ft 2015psi pony tank hydro tested. I didn't use it right away but when I did I noticed it was at 3000psi. I figured it was my small gauge on my utility tire filling reg. The second time I was present when I had it filled and I watched them hot fill it to over 3100psi. When I asked them why I was told all pony tanks where 3000psi, lol... They let some air out and I was mad but went on my way. Could my tank be harmed? Thanks
The greatest danger of overfilling a tank is the blowing of the safety, or extrusion of the neck O-ring. Your tank is probably just fine. However, the safety on a 2015 tank is set for 3200psi (I think I'm right here). Somehow it didn't let go. 1. Find a dive store that is more professional 2. Watch and check the air pressure after a fill 3. If storing if for a long time, don't fill it. 100 to 200psi is all your need. Couple of more things: 1. I had a 1800psi pony. 2015 is odd but 2250 and 3000 is common. Yours may have started life as something other than a scuba tank. My first pony was an old fire extinguisher. 2015 is common for oxygen tanks. 2. The store MUST check every tank for the right fill pressure. I'd be firing that guy!! 3. Don't be afraid to ask to check the tank after a fill. A good dive store won't mind and will even give you a tank checker gauge to do so.
Going by this random web search it is an aluminum 14, all the measurements match. scubatechphilippines.com/scuba_blog/wp-content/uploads/2011/07/Luxfer-metric-cylinder-sp.jpg I'm guessing the burst disc if correct one is installed was about 100psi from bursting. I didn't watch the first fill because I left it there for inspection and the second one was done by I believe the owners wife so she still has a job. I'll be finding another place to fill. If they miss that detail what else do they miss. I keep full tanks around for convenience around the house but perhaps I'll change to a CO2 tank for that. Thanks for your insight!
Good question. I should have mentioned that. The dip tube is there in the very unlikely case that some dirt or water get into your tank. The tube will prevent that dirt or water from going into the valve and into your regulator if, again in the very unlikely case, that you completely invert the tank while diving. However, the regulator also has a filter that would stop any dirt from entering it - not water. So you can see that not having a dip tube, while not normal, is not a big cause for concern. Note that if there's dirt or water in your tank, there's a bigger problem at play that must be solved. Alec
Great video Alec, I wanted to ask, is it safe to leave a cylinder fully pressurised at 230 bar through winter? Do you think it's likely to age the tank prematurely.
Yes. It will prematurely age the cylinder. Mind you, they last 50 years but it's still best to lower the pressure to 100psi if it's not in use for 6 months or more. Realize that the cylinder is stretched when full. Plus there's force on the valve and neck O-ring. Alec
+Alec Peirce European Union regulations dictate that a visual inspection must be performed no longer than the halfway point between hydrostatic testing...thus the requirement is the visual must be done no later than the 30th month since the last hydro...it can be done more frequently. Here in Europe the tanks are impression stamped to indicate the visual was performed. Not sure about Canada but if I recall correctly, in the US they place a sticker on the tank to indicate a visual inspection was performed.
+Jeff Greenfield You're right. We must have a visual every year and it's simply a sticker. BTW, that's an industry standard, only in scuba diving for scuba tanks. There is no 'law'. Other high pressure tanks don't have visuals. That's why there can be discrepancies. In Florida, stores want a visual no more than 6 months old. It is a high volume dive area with a high temperature and salty environment. Plus they have had more than their share of incidents with tanks. Alec
Hah! I have watched with great amusement as divers and even dive store staff have struggled to get a tank onto a tank. Everyone has different ideas on how to do this - most don't work. I've seen divers boil the boot in hot soapy water, smear the tank and boot with grease, even attack the boot with tire irons! The problem is that the boot is designed to be a tight fit. You don't want it coming off. So, of course, it's had to install it. The way I have always done it is very simple, so simple that Diana, and others too, curse at me every time I show them how it's done. 1. Place the boot on a firm floor surface, not carpet. 2. Hold the tank with one hand by the valve about 18" above the boot and steady it with your other hand. 3. Aim down the side of the tank to make it as straight and in line with the boot as possible. 4. Sharply drop and push the tank down until it makes contact with the boot. Make it a follow-through push. That is, don't stop pushing when it contacts the boot. You must make it a hard shove INTO the boot. 50% of the time the tank will spread the top of the boot and slide in. You will almost certainly have to pick up the tank with the partially installed boot hanging from it and drop it onto the floor a few more times to get it fully seated. On a firm floor, you'll hear the difference when the tank reaches the bottom of the boot. With practice, you can increase your success rate to 75% or 90%. Even I missed a couple of times. Good luck. Alec
Good question and that's why a dive store won't fill an empty tank. If the tank has no air in it, there's no way to know what IS in it. So, to answer your question, empty tanks are inspected before filling. Alec
Hi Alec. i just ordered 2 hp steel tanks. with those exact same vales as shown in your vid. now my 1st stage is a din. and i noticed in this video that after you removing the yoke insert i dint notice an "O" ring at the back of the valve for din. maybe im blind or mist it. but shouldnt there be an o ring in there? for din should i be expecting an o ring with my faber order. or will i need to get those or is none needed. your video got me scratching my head a bit
With DIN the O-ring is on the regulator. You will see it on the DIN threaded insert on the reg. There is no O-ring in the valve itself. That is often quoted as a benefit since tank valve O-rings do fail often but that usually lack of care on the diver's part. Alec
Sure. If it has a current hydro stamp (not more than 5 years old) and a current visual sticker (not more than 12 months old), it should be fine. Personally, if I was buying a used tank, I'd want a very recent hydro (2 months old) and a visual from a recognized dive store. Apparently it's possible to buy Visual Stickers on-line and stick them on your own tank! So check it out first. Call the store to be sure. Note as well that new tanks are not expensive - maybe $199. A good used tank may not be worth the small saving.
YS Teo Just take your time to consider if the kind of diving you will be doing merits spending money on a tank. Aside from tank maintenance and inspections, Is it practical for you to be carrying it around to your dive sites? Are you willing to get into enriched air / nitrox? Happy and safe diving mate
Great video but I'd appreciate more detailed info about inspecting the exterior of the tank. Mine has gained a few dings and scratches over the years. Could I know when it is going to fail the test and save myself the six hour round trip to the test center?
Simply, if there is anything on the interior, it requires a second look. A tank insides should be clean and spotless - top to bottom. Not every mark is a reason to fail. Many are normal and some can be properly removed. But, every mark must be evaluated. I'll look into a video on visuals. Alec
Hi, what 3AL stands for? i have an 1985 Luxfer with probably 5 dives and i cant tell if it as the 6351 alloy, scuba shop is telling me to discard it but its like new, how can I be sure? Thanks
3AL means it's an aluminum tank - that's all. It tells you nothing else. There is a list of tanks that are no longer useable but if it's a Luxfer tank, it's simple. Assuming it's an 80 cubic foot tank, if the 1st test date is 1989 or later, it's ok. Prior to 1988 it was probably made from 6351 aluminum and should be replaced. The dive store should give you a trade-in for it. Maybe $50 to $100 off a new tank. Try it. Alec
40-50 dollars!!! Not in Norway. Over here its 100 dollars just for someone to hydrotest it. Cleaning is another matter. May as well buy new every five year here. Another reason to move to Canada 😁
Hardly fair Steven. Lots of "pros" (whatever that means!!) use aluminum 80s even if for convenience. I suggest that divers on a luxury liveaboard in the Maldives or Galapagos are far from "cheap" but they will almost certainly be using aluminum 80s. If you think that you can recognize a pro from the tank he's using, I'm afraid you're in for some unhappy diving experiences. We have lots of newer divers come in to buy a steel tank 'cause it'll make them look like a pro = trouble! I guess someone told them that to be a pro you just have to buy a steel tank. Those steel tanks usually show up on Kijiji a few months later. What do cheap pros use?? Thanks again for your input Steven. Alec
Wow! You must dive only in continental Europe. The aluminum 80 is the standard throughout the Western hemisphere (North America, South America, Caribbean and Pacific. Even when I was in Greece and the Red Sea a couple of years ago, that's all we were given. The aluminum tanks is actually heavier than a comparable capacity steel tank - common misconception. The reason is that an aluminum tank has walls that are twice as thick. The aluminum tank has less buoyancy but NOT less weight. The reason its so popular is also simple - it doesn't rust. In theory and practice, with modest care, an aluminum tanks will last indefinately - that is; forever. Thanks for watching. Alec
okay so if an alu cylinder weights more and has less buoyancy than a steel cylinder then the alu doesn't even have an advantage on surface/land then the steel cylinder is an obvious winner. just because shops are trying to keep things cost effective and give out alu cylinders cause they want to prevent rust and having to buy new cylinders that is why alu cylinders are the standard cylinder.. but in my opinion buoyancy is one of the most important things in scuba diving so the steel tank wins in the water and coming out to land also cause it weights less and as far as rust goes i have had my tank for years and it hasn't rusted yet . with good care your steel cylinder can last a long time and the buoyancy makes it a enjoyable dive. i don't care if had to buy a steel cylinder every six months the buoyancy makes it worth it... people stop being cheap and dive with the best scuba gear and enjoy your dives to it's full potential...
Hi again Steven. Thanks for watching and sharing your ideas. Let me start by saying that I have no agenda. I would definitely prefer if divers purchased steel tanks. I make a lot more by selling steel tanks than aluminum. In fact, I often sell aluminum tanks at a loss as a deal closer! Money is not an issue for me - or you apparently. For many, it is. However, the fact is that steel tanks cost almost 3X the cost of aluminum - $200 versus $500 to $600. There has to be a substantial advantage for one to choose steel. Let's see. Steel tanks, size for size, that is, an 80 cubic foot steel compared to an 80 cf aluminum, are slightly lighter to carry. However, most steel tank lovers opt for larger capacity tanks. We seldom sell any steel tanks less than 100cf and the most common is the 120cf followed by the 130cf. These tanks are heavy. Our staff is not allowed to carry a customer's steel 130cf tank. Many of our steel tank customers use a dolly to transport their tanks. A definite negative (pardon the pun) for many divers who are smaller or older. Also, steel tanks are much more likely to suffer from corrosion. As you say, vigilance in their care will keep them is service almost indefinitely but, that's the case for aluminum without the diver having to be so concerned. So long as either is treated with a modicum of care and is never allowed to go empty, either will last forever. Care and longevity is equal. Besides larger capacity, the main factor in choosing steel tanks is their relative buoyancy. For some diving activities a negatively buoyant tank is an advantage. It may allow you to use less weights and it may allow you to having greater buoyancy control in some circumstances. However, the simple and logical fact is that these are not important factors for the vast majority of divers who dive infrequently and strictly for fun at that. That is, for the occasional recreational diver on his annual trip south with 4 dives on a pretty reef at 50', having a tank that is very slightly negative at the start of the dive is good and having that tank slightly positive at the end of the dive is even better. Let's call this a bonus for aluminum although it's a personal call. Steel tanks cost more to own. Besides the initial cost, many stores charge more to fill a large capacity or overpressure steel tank. Some charge more to perform the annual visual. It is more involved. If the interior shows significant rust it will need to be cleaned before a visual is performed and that has a cost. The 5 year Hydrostatic test costs more since the tank will require extra work for drying plus a rust inhibitor treatment. Definate bonus for aluminum. Good or bad, dive resorts and stores worldwide have chosen the aluminum 80 as their choice of tank. The reasoning is based on the above thoughts but mainly I suppose on the likelihood that the aluminum 80 will last longer in a rental environment where diver care is probably less stringent. So the aluminum 80 is the most common tank encountered both in local rental and while traveling. I'd say that's a bonus for the aluminum tank. So, while each diver chooses and should choose the tank that is best for their diving activities and personal preferences, there are clear advantages to the aluminum 80 for the vast majority. Again, please, please buy a steel tank in my store (luv ya) but please don't say it's the best tank for all divers to use. That is simply not the case.
i would always suggest trying both steel and alu cylinders before deciding which is best for you...... i would definitely buy a steel tank from you when i need one..
Alec, you do such a cool put down to anyone who puts on bad comments, "if they're not useful, then don't watch!!" brilliant, you're a bro!
Good stuff as always :)
Down here in Australia we have to have the Hydrostatic test done once a year and it's more expensive like $100 which feels like over-kill
Oh wow! Bet your incident of tank failures is very very low. North America is 5 years hydro and 1 year Visual Inspection. Stay safe and cool my friend.
This is only barely referred to in the SCUBA certification course -- very nice to have it explained at length.
Very enlightning video, as usual. Keep these nice videos coming. Greetings from Rio de Janeiro, Brazil.
Dear " maestro " if people are teaching any subjects like you do; everyone will be out of the streets and have a good job or at list enjoy a better quality life!!!
As Amalfi coast and in general Italian coasts scuba diver of over 55 years ( I am 59, early years in Apnea ) I applaude you and thank you!!! Grazie molte.
Thanks very much for the compliment Armando. I hope you're watching my 'Vintage Scuba' playlist. You certainly qualify!
I'm not a 'special' teacher. I just keep it simple, no fancy and unnecessary stuff if I can avoid it.
Thanks for watching.
Alec
Thanks Alec for the videos. You seem like a nice dude. Seriously though the videos are well paced, concise and entertaining.
I--for one--learn something valuable in almost every word Alec. Thanks for everything.
Wow! That's a lot of words Raymond but I appreciate the support. See Diver Dave's comment below.
Thank you for watching. Alec
I totally agree . I personally look my tanks over everytime fill them once a year i have them inspected
After all its my life .
It's not a toy, it is your life and that is what many divers forget/ignore. Many divers take better care of their car hub caps! Thanks for the feedback.
Hi Alec,
I just recently started SCUBA diving and I wanted to thank you for your continued effort putting out all these videos with all that valuable information.
From what I've gathered so far DIN valve steel tanks are a lot more common in Europe than INT valve aluminum (or INT steel?) tanks. DIN interconnects seem to have the benefit of being able to easily convert to INT with the inexpensive yoke adapter and the added benefit of being able to handle up to 300 bar (~4350 psi) with the appropriately rated tanks. The INT interconnect seems to be able to only handle 200 bar (~2900 psi) operating pressure.
I am not sure what the situation is like in Northern America regarding 300 bar fillings of tanks, but I feel that if you are in need of a bit more air, the DIN / 300 bar combination of regulator and tank might be the slightly more flexible but also heavier solution compared to INT / 200 bar.
Service intervals for tanks are the same as john b mentioned here in Germany. Maybe because of universal European regulations? I don't know for sure.
I'm sure you know all this, I just felt like sharing this information.
Anyway, keep the Tech Tips comming. :)
+oBsRVr666
Thanks for your comments.
You are quite right. The DIN is needed for higher pressure tanks. That's all.
They are NOT better valves nor a better system, a better seal or anything else. The trapped O-ring design of a DIN valve is needed for pressures over 3500psi.
So if you're using higher capacity tanks or any tank that is filled to 3500psi or more, you'll be using DIN.
If you're using standard 3000psi tanks, the yoke is not only perfect but it's cheaper, just as solid and quicker to mount.
Some divers want the increased negative buoyancy of a steel tank but do not want to use DIN so you can now get steel tanks rated to 3442psi.
Someone asked why 3442psi. The answer is simple and you now know the answer - DIN is not needed at 3442. 60psi more and a DIN valve is needed with increased cost for both the valve and the regulator.
The best comparison is an outboard motor. It's almost impossible to buy a 10 horsepower outboard. You can get 9.5, 9.7 even 9.9, but not 10. Why?
At 10 hp, the standards for manufacture of the engine increase substantially and so does the cost. So a 9.9hp motor might cost $900; a 10hp would cost $2000.
+Scuba 2000 You make a good point but:
INT system uses 2 O-rings (if the valve is convertible with an DIN/INT adapter - like in this video)
DIN system uses only one O-ring
INT system is great for dive centers because is easier to mount and there they should have plenty of spare O-rings
DIN system is better for personal use, not only because it holds 300 bar but also it's lighter, you have a smaller profile ...
Thanks for sharing this info. I found your explanation and information extremely useful. You should have a show.
Wow, thanks!
Thank you, Alec. This was very informative.
Thanks for watching James.
Alec
Great job, as usual!
Excellent summary!
Hi Alec, great video!
However, I also have a question regarding steel cylinders. I was curious about the process companies use to prevent rust from forming on steel tanks after they preform a hydrostatic test on the cylinders, do they use chemicals to protect the tank or another method such as filling the tank with some kind of oil instead of water? I hope this question isn't repetitive, I just couldn't find to much on the web about this subject. Thanks.
Here in Sweden alu-cylinders are almost only used for stage/deco tanks. I'd guess it's because of the buoyancy "benefit" of the empty steel tank when diving in cold waters. So aluminum cylinders aren't likely to be seen here in Sweden.
Interesting video tho!
Why do people use low pressure tank vs high pressure tanks? I’d love to see a video about it if it’s a long answer? Does the buoyancy characteristic change? Can you hot fill a low pressure tank? Thanks for the great videos🙏🏻
Great suggestion! Added it to my ideas list.
so whats the advantage of alu cylinder other than rust/resistant???
Alec, is it common practice to pull a vacuum on a serviced cylinder? I know in HVAC, you pull a vacuum after you open the system to remove any moisture that might be in there. Seems like it might be adventitious for scuba cylinders as well, since water causes corrosion.
Just wondering.
We don't do that. In fact very few high pressure cylinders, even oxygen, are vacuumed.
It's hard to do, costly and for scuba, not a big advantage.
Our tanks are mainly aluminum and contain 80 cubic feet or more.
And the air we use is very dry so generally we simply fill the tank with dry air. The ambient volume of the tank is very small so a couple of fills with dry air and it's dry in there!!
Alec
Assuming no abuse or damage, can a tank be filled literally hundreds of times through the years and still be safe so long as it has not gone beyond it's expiration date? I'm just trying to understand what actually contributes to a failed test; pressurization cycles, time, or some combination.
Your tank stretches and shrinks every time you fill it and empty it. It's actually quite measurable.
As with any metal, if it is bent back and forth it loses elasticity and becomes brittle. Think about a wire coat hanger which you can break by bending rapidly many times. When a tank becomes brittle, it will not stretch when being filled and will shatter.
Granted, it takes thousands of bends (or stretch/shrink cycles) for this to happen but there are so many variables that a 5 years test period of the tanks remaining elasticity is reasonable.
So, to answer your question, it is not time, temperature or any other factor other than pressurization cycles - stretch and shrink cycles if you like.
Alec
@@AlecPeirceScuba_SeaHunter That's good to know. I use my (aluminum) tank strictly in the back yard swimming pool as I am not a diver. It helps when doing underwater repairs, but also is used occasionally for recreation. It's only been refilled literally a few times over the many years, and I purchased it brand new. However, it has never been hydro-tested. For that matter, I also have a couple CO2 tanks. Same story. All my tanks have never been abused or damaged, nor have they ever come close to having zero pressure (contamination risk). Based on all that, I would presume that they are relatively safe. I know you cannot advise other than what industry standards/law prescribes, nor would I want you to. That said, just curious your opinion of my risk assessment.
Pretty low risk I'd say.
You should know that it's best to store tanks with low pressure rather than filled.
I know that's a nuisance since you have to go and get them filled to use but storing for long periods under high presure can lead to slightly shorter life. It's not really a big deal but good to know.
Perhaps you could live with the scuba tank at say 1500 psi instead of 3000. That will still give you 45 minutes+ in a pool.
Take care.
Alec
Hi Alec,
Firstly I would like to thank you for all amazing information you are providing.
I need help, I have 18L tank, how can I know how many CU FT of this tank? I’m not able to fit properly my Eon Core on this tank.
I checked and this is a good comparison from Australia:
Using standard Australian Sizes:
10L tank = 80 cu ft tank (when filled to 226.5 bar / 3285 psi)
12L tank = 100 cu ft tank (when filled to 236 bar / 3420 psi)
15L tank = 125 cu ft tank (when filled to 236 bar / 3420 psi)
18L tank = 150 cu ft tank (when filled to 236 bar / 3420 psi)
please note these calculations are using Australian conversions where 1 ata = 1 bar = 14.5 psi and 1 cu ft = 28.32 Litres.
Thank you for the great content! For the hydrostatic test, does that also include a visual inspection? Or if your tank has been out of test for a number of years would you require both hydro and visual tests to be undertaken? Cheers.
A tank well past its annual Visual Inspection date is Visual Inspected before hydro testing as the tank must be empty and valve removed anyway.
great video
Well, Ultimate. What can I say?
You must have binge-watched my Vintage Scuba videos.
I appreciate that and I'm glad you enjoyed them.
This is a single answer to all your comments (sorry).
I watched your UA-cam video of diving with the US Diver 2 hose. We wouldn't really consider that a vintage regulator you know,. But it's neat all the same.
I also saw your speargun collection.
I have dozens of them and am slowly selling them off, along with most of the stuff you've seen in my vids.
Subscribe to my eBay site and watch it. I list a bunch and then rest for a while so don't give up.
Or you can ask me for things that you're looking for. Reach me at seahunter@vintagescuba.com .
Take care.
Alec
Thanks for your vids, I especially like the vintage equipment ones. My question is about Hydro testing and more specifically over filling. A while back I had my 14 cu ft 2015psi pony tank hydro tested. I didn't use it right away but when I did I noticed it was at 3000psi. I figured it was my small gauge on my utility tire filling reg. The second time I was present when I had it filled and I watched them hot fill it to over 3100psi. When I asked them why I was told all pony tanks where 3000psi, lol... They let some air out and I was mad but went on my way. Could my tank be harmed? Thanks
The greatest danger of overfilling a tank is the blowing of the safety, or extrusion of the neck O-ring. Your tank is probably just fine. However, the safety on a 2015 tank is set for 3200psi (I think I'm right here). Somehow it didn't let go.
1. Find a dive store that is more professional
2. Watch and check the air pressure after a fill
3. If storing if for a long time, don't fill it. 100 to 200psi is all your need.
Couple of more things:
1. I had a 1800psi pony. 2015 is odd but 2250 and 3000 is common. Yours may have started life as something other than a scuba tank. My first pony was an old fire extinguisher. 2015 is common for oxygen tanks.
2. The store MUST check every tank for the right fill pressure. I'd be firing that guy!!
3. Don't be afraid to ask to check the tank after a fill. A good dive store won't mind and will even give you a tank checker gauge to do so.
Going by this random web search it is an aluminum 14, all the measurements match.
scubatechphilippines.com/scuba_blog/wp-content/uploads/2011/07/Luxfer-metric-cylinder-sp.jpg
I'm guessing the burst disc if correct one is installed was about 100psi from bursting. I didn't watch the first fill because I left it there for inspection and the second one was done by I believe the owners wife so she still has a job. I'll be finding another place to fill. If they miss that detail what else do they miss. I keep full tanks around for convenience around the house but perhaps I'll change to a CO2 tank for that. Thanks for your insight!
hey Alec, I was wondering if my tank will work without a dip tube
Good question. I should have mentioned that.
The dip tube is there in the very unlikely case that some dirt or water get into your tank.
The tube will prevent that dirt or water from going into the valve and into your regulator if, again in the very unlikely case, that you completely invert the tank while diving.
However, the regulator also has a filter that would stop any dirt from entering it - not water.
So you can see that not having a dip tube, while not normal, is not a big cause for concern.
Note that if there's dirt or water in your tank, there's a bigger problem at play that must be solved.
Alec
Great video Alec, I wanted to ask, is it safe to leave a cylinder fully pressurised at 230 bar through winter? Do you think it's likely to age the tank prematurely.
Yes. It will prematurely age the cylinder.
Mind you, they last 50 years but it's still best to lower the pressure to 100psi if it's not in use for 6 months or more.
Realize that the cylinder is stretched when full. Plus there's force on the valve and neck O-ring.
Alec
only a visual every 2 1/2 years and hydro 5 here in UK :)
+Alec Peirce European Union regulations dictate that a visual inspection must be performed no longer than the halfway point between hydrostatic testing...thus the requirement is the visual must be done no later than the 30th month since the last hydro...it can be done more frequently. Here in Europe the tanks are impression stamped to indicate the visual was performed. Not sure about Canada but if I recall correctly, in the US they place a sticker on the tank to indicate a visual inspection was performed.
+Jeff Greenfield
You're right. We must have a visual every year and it's simply a sticker. BTW, that's an industry standard, only in scuba diving for scuba tanks. There is no 'law'. Other high pressure tanks don't have visuals. That's why there can be discrepancies. In Florida, stores want a visual no more than 6 months old. It is a high volume dive area with a high temperature and salty environment. Plus they have had more than their share of incidents with tanks.
Alec
great, thanks
In Germany we nearly only can rent 12-15 liter steel tanks :)
That should be good for any recreational diver. If not, doubles.
how do you put the boot on the bottom of the tank?
Hah! I have watched with great amusement as divers and even dive store staff have struggled to get a tank onto a tank.
Everyone has different ideas on how to do this - most don't work.
I've seen divers boil the boot in hot soapy water, smear the tank and boot with grease, even attack the boot with tire irons!
The problem is that the boot is designed to be a tight fit. You don't want it coming off. So, of course, it's had to install it.
The way I have always done it is very simple, so simple that Diana, and others too, curse at me every time I show them how it's done.
1. Place the boot on a firm floor surface, not carpet.
2. Hold the tank with one hand by the valve about 18" above the boot and steady it with your other hand.
3. Aim down the side of the tank to make it as straight and in line with the boot as possible.
4. Sharply drop and push the tank down until it makes contact with the boot. Make it a follow-through push. That is, don't stop
pushing when it contacts the boot. You must make it a hard shove INTO the boot.
50% of the time the tank will spread the top of the boot and slide in. You will almost certainly have to pick up the tank with the partially installed boot hanging from it and drop it onto the floor a few more times to get it fully seated. On a firm floor, you'll hear the difference when the tank reaches the bottom of the boot.
With practice, you can increase your success rate to 75% or 90%. Even I missed a couple of times.
Good luck.
Alec
How do they fill them with certainty there is no moisture or debris in them?
Good question and that's why a dive store won't fill an empty tank.
If the tank has no air in it, there's no way to know what IS in it.
So, to answer your question, empty tanks are inspected before filling.
Alec
Hi Alec.
i just ordered 2 hp steel tanks.
with those exact same vales as shown in your vid.
now my 1st stage is a din.
and i noticed in this video that after you removing the yoke insert i dint notice an "O" ring
at the back of the valve for din.
maybe im blind or mist it.
but shouldnt there be an o ring in there? for din
should i be expecting an o ring with my faber order.
or will i need to get those or is none needed.
your video got me scratching my head a bit
With DIN the O-ring is on the regulator. You will see it on the DIN threaded insert on the reg.
There is no O-ring in the valve itself.
That is often quoted as a benefit since tank valve O-rings do fail often but that usually lack of care on the diver's part.
Alec
I love all these videos. I’m getting back into diving after a 10 year break! I’ve got to get my tanks inspected and my regulator serviced
Hi, I am a new OW.
Is it okay to buy a used tank with 5-7 stamps?
Sure. If it has a current hydro stamp (not more than 5 years old) and a current visual sticker (not more than 12 months old), it should be fine. Personally, if I was buying a used tank, I'd want a very recent hydro (2 months old) and a visual from a recognized dive store. Apparently it's possible to buy Visual Stickers on-line and stick them on your own tank! So check it out first. Call the store to be sure. Note as well that new tanks are not expensive - maybe $199. A good used tank may not be worth the small saving.
YS Teo Just take your time to consider if the kind of diving you will be doing merits spending money on a tank. Aside from tank maintenance and inspections, Is it practical for you to be carrying it around to your dive sites? Are you willing to get into enriched air / nitrox?
Happy and safe diving mate
Great video but I'd appreciate more detailed info about inspecting the exterior of the tank. Mine has gained a few dings and scratches over the years. Could I know when it is going to fail the test and save myself the six hour round trip to the test center?
Simply, if there is anything on the interior, it requires a second look.
A tank insides should be clean and spotless - top to bottom.
Not every mark is a reason to fail. Many are normal and some can be properly removed.
But, every mark must be evaluated.
I'll look into a video on visuals.
Alec
Thank you Alec. That would be brilliant!
Hi, what 3AL stands for? i have an 1985 Luxfer with probably 5 dives and i cant tell if it as the 6351 alloy, scuba shop is telling me to discard it but its like new, how can I be sure? Thanks
3AL means it's an aluminum tank - that's all. It tells you nothing else.
There is a list of tanks that are no longer useable but if it's a Luxfer tank, it's simple.
Assuming it's an 80 cubic foot tank, if the 1st test date is 1989 or later, it's ok.
Prior to 1988 it was probably made from 6351 aluminum and should be replaced.
The dive store should give you a trade-in for it. Maybe $50 to $100 off a new tank.
Try it.
Alec
Alec Peirce Scuba Thank you for your quick reply really appreciated your input
great explanation but a better video would be how do they fill it with air and see that it is ready to go
We did that. Keep watching John.
Take care.
Alec
@@AlecPeirceScuba_SeaHunter you are right found your video of filling air station, sorry
Is minor pitting passable......
There is an acceptable amount of pitting allowed and the inspector actually has a tool to measure it to determine pass/fail.
Thanks
Thanks for watching Joe.
Alec
40-50 dollars!!! Not in Norway. Over here its 100 dollars just for someone to hydrotest it. Cleaning is another matter. May as well buy new every five year here. Another reason to move to Canada 😁
Your welcome and will love our winter ice diving.
steel cylinder= for pros..................
aluminum cylinder= cheap people
Hardly fair Steven.
Lots of "pros" (whatever that means!!) use aluminum 80s even if for convenience.
I suggest that divers on a luxury liveaboard in the Maldives or Galapagos are far from "cheap" but they will almost certainly be using aluminum 80s.
If you think that you can recognize a pro from the tank he's using, I'm afraid you're in for some unhappy diving experiences. We have lots of newer divers come in to buy a steel tank 'cause it'll make them look like a pro = trouble! I guess someone told them that to be a pro you just have to buy a steel tank. Those steel tanks usually show up on Kijiji a few months later.
What do cheap pros use??
Thanks again for your input Steven.
Alec
steel tanks are better then aluminum tanks. my cylinder is made of steel.
Out of curiosity, as someone who has never even seen an alu cylinder; whats the advantage of alu other than weight at surface/land?
Wow! You must dive only in continental Europe.
The aluminum 80 is the standard throughout the Western hemisphere (North America, South America, Caribbean and Pacific. Even when I was in Greece and the Red Sea a couple of years ago, that's all we were given.
The aluminum tanks is actually heavier than a comparable capacity steel tank - common misconception.
The reason is that an aluminum tank has walls that are twice as thick. The aluminum tank has less buoyancy but NOT less weight.
The reason its so popular is also simple - it doesn't rust. In theory and practice, with modest care, an aluminum tanks will last indefinately - that is; forever.
Thanks for watching.
Alec
okay so if an alu cylinder weights more and has less buoyancy than a steel cylinder then the alu doesn't even have an advantage on surface/land then the steel cylinder is an obvious winner. just because shops are trying to keep things cost effective and give out alu cylinders cause they want to prevent rust and having to buy new cylinders that is why alu cylinders are the standard cylinder.. but in my opinion buoyancy is one of the most important things in scuba diving so the steel tank wins in the water and coming out to land also cause it weights less and as far as rust goes i have had my tank for years and it hasn't rusted yet . with good care your steel cylinder can last a long time and the buoyancy makes it a enjoyable dive. i don't care if had to buy a steel cylinder every six months the buoyancy makes it worth it... people stop being cheap and dive with the best scuba gear and enjoy your dives to it's full potential...
Hi again Steven.
Thanks for watching and sharing your ideas.
Let me start by saying that I have no agenda. I would definitely prefer if divers purchased steel tanks. I make a lot more by selling steel tanks than aluminum. In fact, I often sell aluminum tanks at a loss as a deal closer! Money is not an issue for me - or you apparently. For many, it is.
However, the fact is that steel tanks cost almost 3X the cost of aluminum - $200 versus $500 to $600.
There has to be a substantial advantage for one to choose steel.
Let's see.
Steel tanks, size for size, that is, an 80 cubic foot steel compared to an 80 cf aluminum, are slightly lighter to carry.
However, most steel tank lovers opt for larger capacity tanks. We seldom sell any steel tanks less than 100cf and the most common is the 120cf followed by the 130cf. These tanks are heavy. Our staff is not allowed to carry a customer's steel 130cf tank. Many of our steel tank customers use a dolly to transport their tanks. A definite negative (pardon the pun) for many divers who are smaller or older.
Also, steel tanks are much more likely to suffer from corrosion. As you say, vigilance in their care will keep them is service almost indefinitely but, that's the case for aluminum without the diver having to be so concerned. So long as either is treated with a modicum of care and is never allowed to go empty, either will last forever. Care and longevity is equal.
Besides larger capacity, the main factor in choosing steel tanks is their relative buoyancy. For some diving activities a negatively buoyant tank is an advantage. It may allow you to use less weights and it may allow you to having greater buoyancy control in some circumstances. However, the simple and logical fact is that these are not important factors for the vast majority of divers who dive infrequently and strictly for fun at that. That is, for the occasional recreational diver on his annual trip south with 4 dives on a pretty reef at 50', having a tank that is very slightly negative at the start of the dive is good and having that tank slightly positive at the end of the dive is even better. Let's call this a bonus for aluminum although it's a personal call.
Steel tanks cost more to own. Besides the initial cost, many stores charge more to fill a large capacity or overpressure steel tank. Some charge more to perform the annual visual. It is more involved. If the interior shows significant rust it will need to be cleaned before a visual is performed and that has a cost. The 5 year Hydrostatic test costs more since the tank will require extra work for drying plus a rust inhibitor treatment.
Definate bonus for aluminum.
Good or bad, dive resorts and stores worldwide have chosen the aluminum 80 as their choice of tank. The reasoning is based on the above thoughts but mainly I suppose on the likelihood that the aluminum 80 will last longer in a rental environment where diver care is probably less stringent. So the aluminum 80 is the most common tank encountered both in local rental and while traveling. I'd say that's a bonus for the aluminum tank.
So, while each diver chooses and should choose the tank that is best for their diving activities and personal preferences, there are clear advantages to the aluminum 80 for the vast majority.
Again, please, please buy a steel tank in my store (luv ya) but please don't say it's the best tank for all divers to use. That is simply not the case.
i would always suggest trying both steel and alu cylinders before deciding which is best for you......
i would definitely buy a steel tank from you when i need one..