I'm not convinced. Even when taking 10 minutes to fill a steel tank it will get hot and cause a pressure drop after cooling. In a well designed fill Station it's not that hard to avoid water getting near the fill whip, while still reaping the benefits of active cooling with water. And why would that increase the risk of overfilling, if you have a properly calibrated safety valve in your station? My compressor doesn't go above 230bar, no matter if I fill in water or dry. It's not like I'm filling below freezing and then heating the tank up, which would raise pressure after filling. I'm just keeping the temp constant instead of allowing it to rise by aiding thermal conductivity. Air doesn't do that very well.

@AlecPeirceScuba_SeaHunter

Ай бұрын

The use of tank water baths is rapidly decreasing. Primarily due to the problem with water around a filling station and the extra problems of water in the shop. Count the number of LDS fill stations using water baths and it's like a very small percentage of all filling stations. Be safe when filling. A

When i fill a 80cuft to 3000psi, let it cool Down to room temperature, it has about 300psi less… so filling it in water to keep it cooler while filling does not mean you automatically overfill it (90l / minute compressor)

@papaspeleo

2 ай бұрын

In france (lot cavedive center) they fill in an old cooling tank for milk and it give you for sure the pressure you asked for. It is no problem for tanks, safety test (in the EUSSR) is done at 1,5 times the workpressure. All the best

@AlecPeirceScuba_SeaHunter

2 ай бұрын

That is the recommended process by tank filling companies and tank makers. Slow, cool, slow, cool and top up. Problem is very impatient divers wanting a 10 min fill of a 3442 psi tank! Up to the tank filler to do it right or educate the diver but safety cannot be skipped. A

@markushesse3970

2 ай бұрын

@@papaspeleo same here in Germany, I just leave the tank standing in cold air after first fill (in winter), theres a pub next. A large beer or two, then it’s time to top up (and it’s little less than 30 bars then, not just 5-6 breaths). But merci beaucoup for the „ EUSSR“, love it!!

Sorry but marginally overfilling a tank does NOT damage a (modern) tank. Tanks are filled to well within their ELASTIC limits, even the 5 yearly (in the EU) overpressure certification test,which is typically at 50% or more over pressure) is still an elastic tank deformation, ie the tank returns to it's original dimensions after the test (it will fail that test if the deformation is appreciably plastic ie irreversable). So what we are talking about here is low cycle fatigue, and for steel and alluminium at the strains seen in scuba tank useage, we are talking many tens of thousands of cycles to appreciably weaken the tank (mostly through work hardening for ally tanks, steel tanks are pretty much completely un-affected). So honestly, how many times have you filled your tanks? Even if you dive 3 times a day for 10 years thats just 10k cycles,not even on the bottom of the graph for a steel tank, and perhaps 1 or 2% onto it for an ally one. It's also pretty much impossible to get any significant water into a scuba tank during refilling as the tank is almost always at some positive pressure. Even 1 bar remaining in the tank, a pressure that you certianly wouldn't want to finish the last dive at...) is 10m of water column, so unless that are filling it at the deep end of a VERY deep swimming pool then really the only way water can get in is a small amount of water trapped in the fill whip threads / fitting, which, say 0.5cc in 10,000cc is less than the amount of water that's gonna get in there through the compressor (especially if that compressors PMV is not properly adjusted, the main reason people get "wet" fills)

@AlecPeirceScuba_SeaHunter

Ай бұрын

We will have to disagree on tank water baths. My final point is how many fill stations out of all around you still use tank baths? Not many and decreasing is my guess. Take care. A

Great video ! Thanks. Been filling my LP 85 to 3600 PSI since day one. (They)oh you reduce the life of the tank. It’s been 17 years and they still pass Hydro. So what does reducing life of the tank mean? And if I get 45 years out of the tank instead of 50 years and I’ve been getting 3600 pounds instead of 2400 and have a greater Diving experience more bottom time what’s really better?

@AlecPeirceScuba_SeaHunter

Ай бұрын

It's still overfilling so do be careful. Regular VIS and hydro are really important so stay safe. A

Love your videos. I am here in Florida and I dive steel Low Pressure 108s. In the winter when I get fills in the outdoor water tanks it typically in the 30s I get fills to 3500. When I get in the 72 deg spring water and do my checks before the dive my tanks will drift up to 3800 to 3900. Which gives me a much longer dive. I dive side mount so the extra psi adds up especially with the LP 108s.

@AlecPeirceScuba_SeaHunter

Ай бұрын

Those are big boy tanks! Good for long spring dives. A

Hey Alec! I saw in this video that in one of your inserts you were at Silver Springs ( glass-bottom boat in the background)! I remember that! 😎

@AlecPeirceScuba_SeaHunter

Ай бұрын

Yes sir. Sea Hunt Forever 2017 & 2019. Good fun with my vintage friends. A

I was taught to use water when filling tanks and I think it can still make business sense. Our compressor ran fast enough that if I filled them to 200bar, they'd be somewhere from 180-190bar after cooling down. We had complaints from guests about that, so the choice was a) overfill to compensate, or b) cool them down with water while filling. As a dive center having to choose between: - unhappy guests who don't get their expected 200bar - slight risk of some water getting in (which can be negated by being careful) - guaranteed shorter lifespan due to overfilling The slight water risk seems like the lesser of 3 evils

@mikkosport2300

2 ай бұрын

It's just about physics: (P1*V1)/T1 = (P2*V2)/T2, where P is pressure, V volume and T temperature (in Kelvins). If volume stays constant (i.e. the tank) the pressure has to drop when temperature drops. Colling about 15 Kelvins(e.g fron 315 to 300K i.e near room temperature) means about 5% loss of pressure. This time Alex has misunderstood the physics, I asume.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

I ran many dive shops and had the same issues. My solution was no water bath as is didn't cool the tank air, just the outside and only slightly during a 20-30 min fill. Customers got a full 3,000 psi when cooled to room temp. Very few complaints, cleaner fill area, better smelling (oh yes). Everyone has to pick which solution to use and deal with customers. Safe filling. A

I love your videos Alec, you should write a book like Dottie Frazier about your life ! All the best from the UK, Dale

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Maybe one day someone will. I think between my two KZread channels I have shared more than any book could hold. Thanks for watching. A

Hi Alec, Down in Sydney (Australia) Frog Dive - (great name for a Dive Store) has a refrigeration unit that he runs his lines through pre-compression, this is mainly to allow for condensation of water vapour pre compressor and thus a much drier air hitting his air bank, but he also has his post bank air run through another chiller so that when it his the tank for a fill it's at a lower temperature and improves the fill temp and pressure (Charles's Law comes into play). Theoretically if the gas is cold enough you should be able to put a set volume in at a certain temperature and the tank will not expand, therefore eliminating the thermal expansion stress on the cylinder. What I will mention is that a lot of dive stores in Australia refuse to fill ANY cylinder where the manufacture date is greater than 20 years old - not sure how they come up with this number as it defies the laws of physics. But then again we are the only country in the world which requires annual visual and hydrostatic testing - would love to hear your thoughts on that in a video.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Did not know any country hand a date limit on tanks. My vintage divers would freak out as we use 1960's era steel 72's in single and doubles. I don't see annual hydro testing being that beneficial as annual VIS would detect early cracks. Love the store name and unique compressor setup. I did several videos on hydro testing, process mostly, not country specific. May be a good idea, thanks. A

@ppsselwyn

2 ай бұрын

Not the only country. NZ does the same. Hydro one year, visual the next. Repeat.

@Arjen1992

Ай бұрын

Same for Spain, once a year.

Thank you Alec great points I was actually thinking about this watching my tank get filled today steel cylinder .

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Glad I you liked it. Looks like lots of feedback from views on this topic. A

The term thermal conductivity is a measure of how well a material conducts heat (W/m K). Heat transfer occurs more rapidly through materials with higher thermal conductivities. Steel, for example, with an approximate thermal conductivity of 50.2 W/m K transfers heat more slowly than aluminum (~205 W/m K). This means that aluminum dissipates heat up to 4.5 times faster than steel. And since there is at least double the material in an aluminum tank vs a steel tank that means that the 4.5 becomes at least 9 times faster heat dissipation for an aluminum tank, vs a steel tank. And that is why steel tanks are hotter than aluminum tanks, when being filled .

@maxtorque2277

2 ай бұрын

It's more to do with the specific heat capacities of the material not the thermal impedance! Ultimately the heat leaves the exterior surface of the tank through convection and radiation.

@AlecPeirceScuba_SeaHunter

Ай бұрын

You math is not perfect. I prefer to use what the pros publish such as PCI which is the authority on scuba tanks and filling. Safe diving my friend. A

I learn something every time

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Glad to help share some old man knowledge. A

I can understand that somebody can enter water in a tank by prodeeding a sloppy way but in fact, most of the water you can find in a tank is the result of a compressor that draw humid air and that is inadequatly cooled and filtered. the heat produced in the tank is the thermodynamic effect of the pressure rise within the tank.there is no way to get rid of that other than proceed very slowly to permit to the heat generated to be transfered from the compressed .air to the tank wall and to the ambiant atmosphere. so, I believe that dipping the tank in a cool water bath is a good way to cool it while it build pressure and avoid overpressuring it to reach the certification pressure when cooled at room temperature.( I seen 3-400 PSI over certification pressure at inflating to reach certification pressure at room temperature ) If there is humidity to condensate, it will condensate no matter how you fill the tank dipped in a cool bath or at free atmosphere. when the tank will reach its stocking temperature On a fast fill, I prefer that the operator cools the tank because with temperature increase, the material loses its initial properties and is more sensitive to fatigue damage and of course to the overpressure required to deliver a tank to the required pressure. very good topic excellent video.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

It is a personal choice whether to use a water bath or not - at least until the practice is discontinued. There are numerous ways to ensure a good fill without compromising the tank or the operator safety. The best is slow filling. At my last dive shop, where we had lots of tanks to fill. we would commonly fill tanks at a safe rate then disconnect them to work on other tanks. After 15 minutes or more, we would then top up those filled & cooled tanks. Worked for us.

Since you mentioned the elasticity of a tank, I think of an interesting experiment. If you heat up an old / defective tank that has more elasticity left and then let it cool down slowly, it should regain some of the elasticity (not that I would want to use a tank after such a traetment, but it would be an interesting experiment).

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Once stretched, steel does not recover elasticity. Take a coat hanger and straighten it. Now, pick a spot and bend it back & forth many times until you feel the heat. Be careful. It can actually get quite hot. Years ago we did this to get rid of the hook on the end so we could use the wire to break into a car!! It was once common for people to always have a wire coat hanger in their trunk. Now set it aside for a while then go back & start again at the same spot. It will break much sooner than if you start over at a new spot. Metal when stretched will recover but never wholly. Hence Hydro tests. Divers mistakenly think a Hydro Test measures the strength of the tank metal or even the elasticity. Nope! A hydro test measures the amount of permanent loss of elasticity after a tank is stretched. There is always some loss of elasticity, every time your tank is filled. When a tank has lost all of it's elasticity, it can no longer be filled.

When you fill a tank up to 4500psi can you still use a regular first stage? Is the spring strong enough? Thanks for your reply

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Most modern regulators, that is, less than 5 years old, will be rated to 4500psi. Some even higher. But I've never been a fan of taking any piece of technology to the limit. If 4500 is the pressure limit, is 4400 safe?

@indosauro

Ай бұрын

@@AlecPeirceScuba_SeaHunter Totally agree. Mine was just pure curiosity. Thanks for your answer though

Its one thing filling from a static compressor with cylinder banks and radiators where the pressurised air is at ambient, the filled tank stays near ambient. its another where the air is supplied directly from a compressor where the air heats as its compressed.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Certainly some truth to that statement --- assuming the fill is slow. A fast fill from a bank is still going to create more heat.

Is there a site you can go to and check if a hydro stamp is legit? I bought a pony bottle and it looks like separate stamps instead of the normal small four stamp.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

In the USA there is a government web site that listed all valid tank hydro fillers and their stamps (if using a unique stamp). Most tanks are now just MMYY and logged by the tester. Good question to post on www.thescubamuseum.com to see what info is available. A

When I used to dive duals the shops would offer to keep the tank overnight and slow fill it. Any other time I have had tank fills it's always a slam dunk. When I hit the Cool spring water with my hot tank I'm down to about 2,700 right off .

@AlecPeirceScuba_SeaHunter

2 ай бұрын

I know as a shop owner as well that a tank at 3000 psi in the store (even overnight), drops pressure in cool/cold Canadian waters. My answer was usually "what would you do with those missing 5 breaths?". It mostly quieted them down. A

Might I suggest taking the Air Fill Station Technician & VIP Inspector classes (or the equivalent for your preferred training agency ) as a bit of education could clarify some misconceptions. All of these topics are covered with DOT /CCMTA data to justify answers.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Yep! And biennial updates!

It appears the local dive shops have stopped using water tanks. Now tanks are sometimes filled so fast that they are too hot to touch. The shop I am going to now will take my super hot tank and dip it in their swimming pool, cool it down, and add more air. I have often seen my 3500 hp tanks filled to 4000 psi over the past 20+ years. They still pass hydro and VIP. Dive shops are going to do whatever they want regardless of what divergent sides insist.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Getting rid of water baths but then using quick fills & a dip in the pool is simply put, dumbass! There is a proper procedure for filling a scuba tank that reduces the risk to the operator & the diver and does not compromise the integrity of the tank. Any other ad hoc or homemade steps to sidestep that process also sidesteps the reason it exists - to keep the operator, the diver & the tank safe. If your LDS says their their method is OK because they've never had an accident, my suggestion would be to find a modern, professional LDS. Dive shops will do whatever keeps the money rolling in.

I dive light hot-dipped steel tanks which essentially form a corrosion-resistant alloy all over the tank. Faber make them. It is sort of a take the best of both worlds deal. Very light tanks (both lighter than regular steel and aluminium) out of the water, almost neutral in the water (12kg empty with 12l volume) and corrosion-resistant like an aluminium tank. Only drawback other than cost is the fairly low pressure rating of 200 bar. I got mine filled from 0 to 200 bar and ended up with 169 after cooling off. While filling a 232 bar tank still gets you ~200 bar after cooling off. Though this is less of a big deal when you do a more typical fill from 60-100 bar after a dive. These tanks are quite popular in the sidemount community due to the nice buoyancy characteristics.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

I'm still impressed that tanks are still being improved upon. My first was a steel 72 with a 2240 psi fill (only tanks for scuba), and very susceptible to internal rust. So many choices today so enjoy the diving. A

Maybe we need a Refrigerated Containment Fill Station? This would be the best of both worlds keeps the tank cool to achieve a better fill while protecting from tank rupture.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

My opinion is it would be like filling tanks in freezing water, not good for the tank. Take the normal temperature gradient from inside (hot) to outside at 72F then reduce the outside temp to 40F. It introduces a greater temperature gradient which stresses the metal even more. Todays system of SLOW fill, wait, then a SLOW top up to 3100 or 3150 will cool to about 3000 psi. This is both safe and smart for everyone. A

I have been on live aboard dive boats that did not use a water bath. One filled all takes at once that we’re strapped around the boat.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Yes. Me too. Although I have never let anyone fill a tank while still on my back!!

@magiclarry7688

2 ай бұрын

@@AlecPeirceScuba_SeaHunter that is wise……lol

My steel tank is typically filled to 3500 psi by my dive shop... I think I've gotten a few 3600 fills now and then.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

That is actually an overfill if the pressure is say over 3300 psi at 70F. Not a big problem if it's a few times a year, but a dive shop filling it 2 times a day, then you need regular VIS and hydro testing to monitor for acceptable flexing. I knew a dive shop that regularly filled to 3500 then noticed lots of tanks failing hydro. Replacing lots of tanks is very expensive vs an acceptable fill. A

💯💯👌

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Thank you very much. A

I'd also note, whilst i wouldn't want to stand anywhere near a scuba tank that lets go at any pressure, i'd much rather stand near one that lets go in a water bath. No, it won't stop the explosion, but it does massively reduce the exit velocity of the pieces of fractured tank, as water is 1,000 more dense than air. This means if you are a few meters away you stand some chance of not having some important part of you ripped off by the shrapnel. Ok, these days, a lot of modern fill systems now have proper tank "cupboards" that are thick steel and have blow off panels facing away from the front, so a tank letting go during filling in one of those is gonna give you a properly fright, and you'll probably need a change of underwear afterwards ;-) but you ought to walk away from it.....

@AlecPeirceScuba_SeaHunter

2 ай бұрын

There are pictures and stories online about tanks bursting from filling or O2 tanks knocked over. The damage to persons and property was terrible so safe and proper filling, even if the customer takes issue, is first. A

I don't know how accurate it is because I don't see one officially from a manufacturer, but the commonly quoted number is that a tank is good for 10,000 hydro tests. If I get 10,000 dives out of my over filled tanks, I consider the $600 well spent as they are a wear item no different that the parts in my first stage. Even if it is only a 1,000 dives that is still like $0.60 per a dive, far less than the $10 it would cost me to rent a set. I've actually tested it, it was an anecdotal test, but I hooked up a set to the same cascade, one in the back of my car another in a water bath. When they cooled down to 72 degrees the water bath tank was 200psi higher. That might not seem like much, but that might be the difference between a 1,000psi third or a 1,100psi third.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Your analysis is interesting. I have not researched it. 10,000 hydros sounds like a lot. That is essentially 50,000 years of use (hydro every 5 years). You certainly ought to be able to log 1000 dives in 50,000 years!!! I do not quite get the jump in logic to that figure making it OK to overfill. Besides the legality & the increased risk, that will blow your 10,000 hydros out of the water. I fully realize that overfills are quite common. Heck, we did that with old 2250psi tanks back in the 1960s. Being a common practice does not justify it. In theory, if not in practice, tanks filled at the rate of 300psi per minute at room temperature, whether in air or water, should be very close to the same pressure. In my books, 200 is very close. If my dive buddy was trying to calculate his safe dive to an accuracy of 200psi, he would be diving alone! Whatever. Be safe.

@Teampegleg

2 ай бұрын

​@@AlecPeirceScuba_SeaHunter Ignoring the legality of it, as it is questionable that they apply to non-DOT regulated facilities. I've seen arguments for and against, and the DOT doesn't care since the contents aren't hazardous. The risks are minimal with steel tanks, 40 years of cave fills and the only accidents are aluminum tanks which are never over filled. But the logic behind noting that the tanks are good for 10,000 hydros means that they are over engineered, so they have plenty of life for years of over fills. It is a different mindset in that it is acceptable accelerated wear schedule. At some point I will have to condemn them, I will remember all the thousands of dives I've done with them. I will shed a single tear as they are turned into bells, lamps, or whatever. In your books it is fine, but when one is operating by the rule of thirds, 200psi is a big deal because it reduces the whole team's gas limits. If one person has a 1,000psi third because he hot filled it in the back of his car and everyone else slow filled and water bathed to a 1,200psi third, everyone else still has to dive the 1,000psi third. That 200psi is another 5-10 minutes of penetration time.

Concerning Filling the Tank. They develop Microfractures? And like a car tire, Every 10 Degrees F, +or- 1 Degree. I noticed with my Dewalt tire inflator. I'll set it for a specific PSI. As it inflates, Tends to go over .2 to .3 PSI. Once stopped and starts cooling, Drops slightly. I would rather have my AL80 Slowly Filled. You get a better fill. And it's easier to monitor for problems.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

I've not seen anything about "Microfractures" but it makes sense that the cracks start small & grow until they are visible. You're quite right though Chris. Slow & steady still wins the course, or in this case, a good, safe fill.

Need some engineering here. The ideal gas law (simplified) explains the nature of the pressure and volume in relationship with temperature and the ideal gas constant (derived for normal compressible and uniform gases). It is expressed as: P = Pressure. The unit atm (atmosphere) must always be used. V = Volume. This is always measured in liters n = number of moles of gas particles R = ideal gas constant = .08206 T= temperature. This must always be measured with the Kelvin temperature scale Because R is a constant, its value doesn't change from one calculation to the next. Note temp must be expressed in terms of Kelvin so normal 70 degrees (F) is 294 K while 90 F is 305 K. If T goes down then to share the equality and with volume fixed (ignoring the miniscule flex in the tank) then P goes down. Similarly, if T goes up then P goes up. But, the ratio is not 70 F versus 90 F it is 294 K to 305 K. So temp effects are less than one would assume just using the F scale. That said, your points about flexure in the material are sound. What I wonder is the effect of water pressure at depth. ATM at sea level is 14.7 psi and increases 1 atm linearly every 33 feet (approx). Therefore the tank exterior will be presented with 3 ATM overall. Is this flexure not greater than any temp effect ? I think that is also a factor to consider

@richardwilliams9471

2 ай бұрын

PV = nRT not sure why the equation didn’t come out

@Yggdrasil42

2 ай бұрын

@@richardwilliams9471But the ideal gas law doesn't apply with high pressure containers like scuba tanks.

@peterjulianphotos4659

2 ай бұрын

@@Yggdrasil42 Please explain when a Gas Law cannot be applied to high pressure containers- equations and calculus accepted as part of your solution.

@AlecPeirceScuba_SeaHunter

Ай бұрын

Thank you for the feedback. Watch my videos on tanks in the sun for my excellent math: S11E06 Scuba Myths - Tanks In The Sun, and S11E17 Scuba Myths, Tanks In The Sun #2. A

Last thing I heard about a water bath has nothing to do with overfilling. The shop owner fills to the allowed limit, lets it stand in the bath for some time (for a little faster cooling), then tops it up again.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Problem is the chance of water getting into the tank from the bath, a wet whip or just splashing. No water bath is required by law or tank filling makers. It's just a carry over from the early days that is still around. A

If you want a graphic example of the effect of explosive force in water (depth charges a good example), in a container, just look at hydroforming; this being an extreme example of this. kzread.infopm6hM77JD3w?si=eRBhsZDsbEM5y_OE

@AlecPeirceScuba_SeaHunter

2 ай бұрын

I have seen the results of tank failure and that is why my stores did not over fill / rapid fill. My staff were more important than your waiting 30 minutes. A

...mmm WAIT A MINUTE !!! How in the hell is water getting inside of a pressurized tank at the dive shop ??? my LDS will not refill an EMPTY tank until they do a Visual on it .

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Water gets splashed onto the filling whip head so water is PUSHED into the tank when filling. This is how moisture is introduced into the tank. A

@jeffconley6366

2 ай бұрын

I was taught to crack the valve open on the cylinder and the fill whip before attaching to the cylinder to blow any water out. I thought that took care of the problem. This was when I worked in Dive Shops in the 70's and 80's. We filled a lot of cylinders in south florida. We were setup to fill 6 cylinders at a time. If we didn't have the water bath it would have taken a lot longer to fill the cylinders and a lot of unhappy customers.

@diverdave4056

2 ай бұрын

@@jeffconley6366 yes my dive shop did this in the 70's and 80's

Assuming a hot is car is 135 degrees F, and a tank originally at 75 degrees and 3450 psi, would now be at roughly 3800 or so, what is the difference if the the tank was hot when they filled it and they filled it up to around that same pressure? Seems the same to me.

@b.h.8421

2 ай бұрын

Because rapidly cooling it while filling it ensures that the gas put in will condense more because of temperature change. Condensing the gas quickly will allow for more space of incoming gas. This inverse relationship can be illustrated by the noble gas laws: P - pressure V - Volume n - moles or molarity of pressure or partial pressure of any Gas R - Noble Gas Constant (I believe 8.314 ?) T - Temperature PV = nRT or can be arranged as PV/nRT = x if we keep this equation equal to a constant value then we will have to assume that temperature is another term to increase pressure and vice versa. So every time we decrease temperature that means on the other end the pressure will increase to hold that same constant value. I know this can possibly be confusing but I hope I cleared it up none theless

@AlecPeirceScuba_SeaHunter

Ай бұрын

For the proper math around tanks in the sun, watch S11E06 Scuba Myths - Tanks In The Sun, and S11E17 Scuba Myths, Tanks In The Sun #2. A

@Tbm-ov5ky

Ай бұрын

@@AlecPeirceScuba_SeaHunter After watching that video, seems to me there is no difference between a hot fill by the dive store to 3800ish psi and having the same tank in a hot car.

LISTEN TO THE SUBMARINER....

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Will do. A

How does water get into a pressurized system, if the water is not under more than ambient pressure? No different than using your regs. Unless you are using a deco cylinder and the regs weren’t kept pressurized, there will be no water entering your regs. So why would water enter the tank when filling? I’m not condoning overfilling tanks. I just don’t see what harm it causes by putting them in water to keep the tank at ambient temperature while filling. Even when filling under the proper psi per minute, the tank can still get warm. Maybe you lose 200 psi when it cools, which is not a problem in the real world. I’m not arguing any of those points. I am only disagreeing with your reasoning for not to do it, and that is because it can get water in your tank. Doesn’t seem logical.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Water gets splashed onto the fill whip then attached to the tank. High pressure pushes the water, even drop is too much, into the tank. Remember the air fill standards is virtually zero moisture so this is what starts rust/oxidation inside. A

My friend and dinosaur Paul Heinerth is out dated if he uses a tank bath…

@AlecPeirceScuba_SeaHunter

2 ай бұрын

There are still Scuba Instructors who advocate turning the tank valve back 1/2 turn - a long gone necessity!! Some things in scuba diving have not changed in 60 years (I'm thinking!!) but MANY things have. Scuba Instructors undoubtedly drive cars & use mobile phones. Do they think that Scuba is still a medieval sport?? Alec

You talk rubbish. Both steel and aluminum will get hot when filled fast. The rule of thumb is slow slow slower. Sit the tank in a water bath no deeper than half the tank and fill to working pressure. How water is going to get inside the tank while this is happening is beyond me.

@CaliChristopher

2 ай бұрын

Operator drops the whip in the water.

@AlecPeirceScuba_SeaHunter

2 ай бұрын

Drop into our dive store. I am happy to show you just how easily that can happen.

@ketsuno4914

2 ай бұрын

@@CaliChristopher so before connecting it to the tank operator should dry the wip connection.

@CaliChristopher

2 ай бұрын

@@ketsuno4914 “should”, doesn’t mean they do. Why are you arguing for an antiquated method which is frowned upon by the entire industry? Just fill it, let it cool down and then top it off. Why do you want a mess of water dripping all over a shop? It’s unnecessary and has caused issues.