TargetTalk

Ok,
So I need an air tank & regulator for filling a fwb & walther airgun(s) live near beach so is it ok to by a used tank? options? tank the best method?
Any helpful hints regarding this topic including regulators issues would be appreciated. Thanks!!

A tank is certainly the easiest method if you have access to divers' air.

You might find this article useful.

Used air tanks are usually found, at least around here, for $50 to$60 on Craigslist. They usually need an inspection and pressure test before a dive shop will refill them. I have found that many places will refill without that if they know it's just for airgun (paintball shops, too?).

You will not need a regulator for a 3000psi (200 BAR) tank, just a connector to the adaptor for your gun; not very expensive. If you buy a higher pressure tank (not common) and have a 200BAR gun, then you will need a pressure regulator to fill.

For both ease and low price go for the 200 BAR tank. It will last a long time and cost around $10 for a fill.

You don't need a regulator at all. Even with a 300 bar bottle to a 200 bar cylinder on your gun.

All you do is connect, open the tank up slowly, watch the needle on your gauge go up to 200. Close the tank. If you have a screw-on cylinder like most 10m gear does, then unscrew, if you have a fly lead for use with a QF adapter, use the bleed valve on it, then detach.

Simple.

You are better off finding a 300 bar tank, as if you fill at 200 then a 232 bar tank will soon have you looking for it to be refilled. With 300 you will see a lot more fills before you see your pressure drop below your tube's ideal fill pressure. But there's no harm in filling lower, regs in rifles are set at between 60-120 bar so you should see no problems even filling down to 150 bar. Just a lower shot count before refill.

robf wrote:You don't need a regulator at all. Even with a 300 bar bottle to a 200 bar cylinder on your gun.

All you do is connect, open the tank up slowly, watch the needle on your gauge go up to 200. Close the tank. If you have a screw-on cylinder like most 10m gear does, then unscrew, if you have a fly lead for use with a QF adapter, use the bleed valve on it, then detach.

Simple.

You are better off finding a 300 bar tank, as if you fill at 200 then a 232 bar tank will soon have you looking for it to be refilled. With 300 you will see a lot more fills before you see your pressure drop below your tube's ideal fill pressure. But there's no harm in filling lower, regs in rifles are set at between 60-120 bar so you should see no problems even filling down to 150 bar. Just a lower shot count before refill.

I'll agree with Rob, you want a 4500 psi tank so you can top off to 3000 psi. No regulator needed. Depending upon the airgun, you can get 30 - 50 fills before topping off the tank. I personally would not get a scuba tank, I would advise a SCBA tank. I think a SCBA tank at 600 bucks is very inexpensive. With the cost of (5000) pellets and including the cost of a SCBA tank, it is super cheaper than 1 case of Eley. Naturally the second sleeve of pellets is even more cost effective. In a discussion of shooting costs, it is a real bargain. Good luck..

I can't believe I am reading these comments folks.

If you want to kill yourselves or others then go ahead and fill a 200b air rifle cyclinder with a 300b bottle and no regulator.

The danger of inadvertently overfilling by a sudden inflow of air and then having to quickly empty it.........More importantly - overstressing the cylinder is practically impossible to know it has been done. Other than by the person who has done it. And you can guarantee they wouldn't own up to it.

If you happen to later onsell the cyclinder you are endangering yourself while you still have it and then the new owner.

Not to put it too mildly, there is a horrendous amount of energy stored when you compress the air to 200b. 300b is even better!!! A stressed bottle is then almost certainly in a work hardened state and future cycling of the tank from empty to fill will almost certainly improve the chances of it going bang.

When this will happen???? You place the bet. Because I won't.

The risk is too great.

Stick to a 200b bottle for a 200b cyclinder. Leave the 300 b to those with a regulator or a 300b cyclinder.

For training purposes the tank can go down to 150b and you will still get plenty of shots out of it. So what if you have to fill it each night.

If it $10 bucks to fill, then it is cheap insurance.

All of you who know who have done this, let me know and I will make sure I never buy a thing off them. At all.

As an aside here is a trick for maximising your fills for those who have access to two tanks. Fill from the lowest pressure tank first. (Assuming the lowest pressure tank is more tank your cyclinder currectly is holding) Then top up with the highest pressure tank. This is especially so if you have had to empty it. Even the partial fill from a tank with 100b in it will ensure the full tank is maximised.

The article linked to above has this pertinent comment:

"It is NOT recommended that any 300 bar/4300 psi tanks be used at airgun events due to the possibility of someone over pressurizing their 3000 psi rated cylinder. I know some colleges are exploring the possibility of using the 300 bar tank, to get longer service life between tank fills, but this requires extra equipment and extra vigilance to ensure that unsafe overfilling does not occur. From a practical viewpoint, I think the 300 bar tanks not needed, particular given their extra safety concerns."

From the same article about the stored energy:

"The pressurized air normally used is at 3000 PSI (pounds per square inch) and has enormous energy potential. The kinetic energy potential contained within an average SCUBA tank is 1.3 MILLION foot-pounds. This is enough energy to lift a 100-ton diesel locomotive off its tracks and into the air."

RossM wrote:I can't believe I am reading these comments folks.

If you want to kill yourselves or others then go ahead and fill a 200b air rifle cyclinder with a 300b bottle and no regulator.

The danger of inadvertently overfilling by a sudden inflow of air and then having to quickly empty it.........More importantly - overstressing the cylinder is practically impossible to know it has been done. Other than by the person who has done it. And you can guarantee they wouldn't own up to it.

If you happen to later onsell the cyclinder you are endangering yourself while you still have it and then the new owner.

Not to put it too mildly, there is a horrendous amount of energy stored when you compress the air to 200b. 300b is even better!!! A stressed bottle is then almost certainly in a work hardened state and future cycling of the tank from empty to fill will almost certainly improve the chances of it going bang.

When this will happen???? You place the bet. Because I won't.

The risk is too great.

Stick to a 200b bottle for a 200b cyclinder. Leave the 300 b to those with a regulator or a 300b cyclinder.

For training purposes the tank can go down to 150b and you will still get plenty of shots out of it. So what if you have to fill it each night.

If it $10 bucks to fill, then it is cheap insurance.

All of you who know who have done this, let me know and I will make sure I never buy a thing off them. At all.

As an aside here is a trick for maximising your fills for those who have access to two tanks. Fill from the lowest pressure tank first. (Assuming the lowest pressure tank is more tank your cyclinder currectly is holding) Then top up with the highest pressure tank. This is especially so if you have had to empty it. Even the partial fill from a tank with 100b in it will ensure the full tank is maximised.

Airgunning in the UK has been using 300 bar tanks on 200 bar cylinders for about the past 2 decades. There have been a few gauges fail, but they are designed to do so as a weak point. I have never ever heard of a cylinder failing.

Cylinders are run at normal pressure, but they are tested at way higher, for 300 bar, thats around 450 bar. So even if you were daft enough to leave the tap open on a cylinder for long enough to fill it to 300, it's still safe, because the test pressure it must pass to be usable at 232 is over 300.

If you are really nervous, fit a flow restrictor in, and that will take about 2 mins to get up to 300, leaving you with plenty of time to shut a valve down.

There is no need to be hysterical about air as long as you are safe. There is no danger of death then.There is no stress on the gear either if you are careful. It's the same as shooting.

I would be more worried about someone slamming open straight to 200 bar or their tanks never being inspected than topping up from 2-300 bar.

The hysteria is the same thinking that says pressured air cylinders in cargo holds is dangerous because of the lower pressure air outside, without stopping to realise it's a drop of one bar on a system designed and tested to take 100's.

It's moot with my gear, walther's take 300. That said, I won't run them at that because it give the rifle's regs a harder time.

The top 3 SCBA airgun tank sellers in the US sell a complete line of fittings and hoses. I asked all three about regulators and they said they were unnecessary. I think they would require or even recommend a regulator if there was a real liability issue.
Regulators are actually a very high failure system. I know because I work in advanced materials and generally gas is the #1 raw material. Caution and safety should never be ignored, but in this case hysteria should be ignored. If a person is more comfortable with a regulator then use it.

Hysterical? I don't recall being hysterical.

I agree "some" cylinders have been tested to "way above" their useful pressure. I would posit that every cylinder is not taken up to this test pressure. It is a design and test pressure only. I defy any engineer to then tell you that it is "safe" to take it up to that pressure regularly. If ever.

Designing to a greater pressure - in RobF's case to 450b - should be the norm. It does not give carte blanche to use the things at greater pressures than the design pressure.

Some may recall cyclinders now having a 10 year lifetime for competitions now. I don't know the real reason but I suspect (at least) one may have done some damage somewhere. In the article mentioned above one of the reasons which - given what I know about humidity, compressed air and corrosion - may have caused the failure, is that corrosion is one way that a cylinders safety can be compromised.

And one of the easiest methods of putting moisture into cylinders is to use a handpump with no moisture filter in the line. The mere act of compressing air will cause condensation of any moisture in the air. That is why compressors need to be vented of water from their tank regularly.

A very BIG reason why there are few compressed air cylinder accidents these days is not from luck but from a lot of people dying, discovering the physics of what was happening and then developing the engineering and metalurgy that now does a bloody good job of preventing them. People using them - or just filling them - from tanks with higher pressures is, frankly, asking for it. One day the answer will be received and it won't be nice.

And as for 10 years of "cylinder accident free shooting". Hmmm......and for relying on the gauge to act as the pressure relief?????

But all I am doing is questioning the practice. It is not necessary. It is not healthy. Just remember what it was like when you had to pump each and every shot. Filling to 200b and "only" getting 150 to 200 shots from a fill is a small price to pay for a hell of a lot of convenience. Why push the envelope. To me, it is crazy.

PS, just to make sure my hole in the head is not too big: - I work in the Humdiity and Temperature Standards in New Zealand's Measurement Standards Laboratory. The equiv of UKs National Physics Laboratory and the US NIST.

TerryKuz wrote:...I think they would require or even recommend a regulator if there was a real liability issue...

None of things get to be liability matters until there is an 'incident' and the insurance companies and the lawyers get involved - then the brown matter in the baby's nappy hits the ventilation system.

The 200bar and 300bar fittings are (or should be) different, specifically to prevent people from filling a 200bar cylinder from a 300bar source - same thread diameter and pitch but different length.
Bypass or circumvent this safety feature and chances are that YOU carry the liability - good luck.

One thing I had better clarify. Reading my last post makes it appear I am talking about filling 200b cyclinders to 300b. That is not what I mean at all.

What I am trying to suggest is that attempting to fill 200b cyclinders from a 300b tank is to seek trouble from inadvertently overpressurising the 200b cyclinder.

All cyclinders - including dive cyclinders - will expand over time from the cycling from empty (or nearly empty) to full. That is how they test them, the measure their "elasticity" - how much they expand from empty to full. Too much and the tank is rejected.

This MUST happen with air cylinders as well. We do not test them so the powers that be have put in a 10 year blanket lifetime.

Screwing with that lifetime by not following healthy and safe practices should never be condoned.

I use two 350bar, 4500psi carbon fiber air tanks for my PCP's. One is a 17cuft and the other is a 88cuft, on top of that I also have a Hills Air pump which goes to 232bar. (Air Arms S410ERB, and S410 TDR... plus a Walther LP201 which has 300bar cylinders.)

TO reseal a PCP after performing maintenance on the air cylinders an air tank is required to pressurize it so it holds air. When at the house I use the 88cuft tank or the air pump, when hunting or out plinking I use the 17cuft tank. (The PCP air tank goes to 200bar.)

The air tanks DO NOT have regulators on them but do have small air lines which act as flow restrictors, I am confident in filling my PCP's using this method. I would not trust my dad to do the same.

The issue with the air tank is find someone who can do an honest 4500psi fill and who treats it accordingly. The paintball places care less about "safe" handling of air tanks and think a 3800psi fill is good enough. Dive places are a bit better but when the tank cools down it only shows 4100psi. I haven't tried any fire departments and plan to fill them myself for now on to get the true 4500psi fill. Most high pressure fills are moisture free whereas the handpump your at the mercy of environmental conditions. (Not a problem in two years of having my PCP's as both air tanks don't exhibit any internal corrosion.)

RossM wrote:Hysterical? I don't recall being hysterical.

I agree "some" cylinders have been tested to "way above" their useful pressure. I would posit that every cylinder is not taken up to this test pressure. It is a design and test pressure only. I defy any engineer to then tell you that it is "safe" to take it up to that pressure regularly. If ever.

Designing to a greater pressure - in RobF's case to 450b - should be the norm. It does not give carte blanche to use the things at greater pressures than the design pressure.

Some may recall cyclinders now having a 10 year lifetime for competitions now. I don't know the real reason but I suspect (at least) one may have done some damage somewhere. In the article mentioned above one of the reasons which - given what I know about humidity, compressed air and corrosion - may have caused the failure, is that corrosion is one way that a cylinders safety can be compromised.

And one of the easiest methods of putting moisture into cylinders is to use a handpump with no moisture filter in the line. The mere act of compressing air will cause condensation of any moisture in the air. That is why compressors need to be vented of water from their tank regularly.

A very BIG reason why there are few compressed air cylinder accidents these days is not from luck but from a lot of people dying, discovering the physics of what was happening and then developing the engineering and metalurgy that now does a bloody good job of preventing them. People using them - or just filling them - from tanks with higher pressures is, frankly, asking for it. One day the answer will be received and it won't be nice.

And as for 10 years of "cylinder accident free shooting". Hmmm......and for relying on the gauge to act as the pressure relief?????

But all I am doing is questioning the practice. It is not necessary. It is not healthy. Just remember what it was like when you had to pump each and every shot. Filling to 200b and "only" getting 150 to 200 shots from a fill is a small price to pay for a hell of a lot of convenience. Why push the envelope. To me, it is crazy.

PS, just to make sure my hole in the head is not too big: - I work in the Humdiity and Temperature Standards in New Zealand's Measurement Standards Laboratory. The equiv of UKs National Physics Laboratory and the US NIST.

You aren't pushing any envelope. I would have thought that you would realise that 300 going into 200 isn't an instantaneous fill, it is a controlled operation.

You are not asking for it. If you want, i can time the time it takes to fill up to 200 from 100 on a 300 bar bottle and you can say stop. On my restricted flow bottle it will take longer than the time it took to type this reply.

And yes, cylinders are tested. They have a lifespan. Materials meant for such purposes such as tubing are proofed stamped. They have a lifetime because they are not retested.

RobF says:
"And yes, cylinders are tested. They have a lifespan. Materials meant for such purposes such as tubing are proofed stamped. They have a lifetime because they are not retested."

I wish to refer you to the Feinwerkbau notification found on this page here: Pick "Compressed Air Cylinders".

http://www.feinwerkbau.de/ceasy/modules ... PageId=195

Let me quote:

"1. The compressed air cylinders manufactured by FEINWERKBAU are produced according to the German Pressure Vessel Code, but have not to be certified (i.e. by TÜV, etc.). The manufacturer must assure the safety of the compressed air cylinder."

and

"An often so called overhaul or ‘TÜV-Test’ is not possible to extend the lifetime of a compressed air cylinder."

So according to FWB, they do not test them but they make them to the standard and cover their arse by limiting their lifetime. That is their response to their risk assessment.

Asking about this situation from a metallurgist with probably 30+ years of experience backs up my concerns. His comment was that a human in the train of events that can allow higher than design pressures into such cyclinders is defying practically every H&S clause on the planet. He commented that if anyone was found to have a procedure where they were able to - let alone being allowed to - do this would be fired.

I do intend to take this up with FWB, Walther and Anschutz along with the ISSF. It seems to me that it would be useful for the manufacturs to come to some agreement on a common standard pressure and fittings for compressed air rifle/pistol cylinders and supply tanks to use.

And here is the corressponding Anschutz Information:

http://jga.anschuetz-sport.com/index.ph ... %250C%2593

I have not found any from Walther, Steyr (I presume) would come under the Anschutz umbrella(?)

They are manufactured, to a spec. That spec includes using tubing spec'd for the purpose, which is beyond a 200 bar fill.

The answer is in the small print.

For some years ANSCHÜTZ has their compressed air cylinders checked and approved according to the European directive 1999/36/EG

From 1999, they are checked and approved and marked as such. The testing after 10 years is not economically viable, so they are junked.

The spec varies between design and procduction control with inspection by the manufacturer, and it being done to an EC control/inspection. Either way, cylinders are marked.

You won't get far with Walther, they are spec'd to 300 bar fills anyway.

Cylinders used for shooting actually have a better life when left with air in, as the metal is subject to less stress than if they were emptied. I would have far more concerns about a shooter constantly emptying the cylinder and refilling to 200, than going occaisionally over 200 by a few bar.

Question, when you fill, how accurate is your guage? Without looking, tell me how many bar it's error is, and at what temperature is it calibrated to?

It won't probably make you sleep well at night to know that seeing a 20 degree change will have you well over the pressure you are concerned about when filling from a 300 bar bottle and going perhaps 10 bar over by accident.

This is the reason why 200 bar bottles are spec'd to work well beyond 200 bar, because it would be stupid if they were to fail 1-2 bar over because they were left in the back of a car etc, and it would also be stupid to pick just any old ally or steel off the shelf and start a production run of air rifles wouldn't it?

232 air cylinders themselves are designed and meant to pass withstand 7 Thousand fills to 0.9 times test pressure. Test pressure at 20c is 315 bar.
That is 7,000 fills to 315 bar on 232 bar rated tanks, which can get up to 280 bar just on a careless warming when being filled out of water at 200 bar if left to rise to 60c.

I would have thought all this you should know.

Do they just pull tube off the shelf in NZ then? Or do they sneak a peek at the designed purpose and build in a safety margin, do you think?

I do wonder about someone shooting if they can't react quick enough to a fill speed of 1 bar to 5 seconds and stop it at 200.

Thanks for the reply robF.

Time to think about leaving the topic. Beginning to aim at the person rather than the message.

I have never said they will fail at 202 bar. I agreed with your comment about 300b cyclinders being designed to 450b. Where you got the idea I thought 200b cyclinders might be different I'm buggered if I know.

However. You miss the point. You may very well assure me that you can control the knob and turn it off at 200b. Congratulations. But that does nothing to assure me that others do. As I tried to explain, I cannot tell if a cylinder has been overpressurised. Especially so if I do not know - or even if I knew - that someone was filling it from a 300b tank. ONLY filling it from a 200b tank will assure me it was never overpressurised _more than it's design pressure_.

Sorry for being so thick but I don't get your comments about "filling out of water"??

How accurate is my gauge should not bother me at all if I only use a 200 bar tank to fill it. Rather, it is you who should be very concerned about the accuracy of your gauge. As far as what temp it was calibrated at I could safely say anything close to "room temperature" because I wouldn't be able to handle it if it was at 60 degC. Of course I understand the gas laws. eg The benefit of letting the cyclinder cool for a few minutes and then top it up.

As far as "all cylinders being tested". I doubt it. I believe I might be right that a sample of cyclinders were taken and tested by an "approved body" and then batches manufactured and stamped with the approval. The point of the time limit was to eliminate the need to retest all cylinders as is required by the regulations after 10 years.

As FWB (I think) point out, the retest is more expensive than a relacement.

Manufacturer's arse covered. QED.

Good luck with your shooting. I'll stay safe here in the Antipodes well away from the losing English Rugby team. :-)

RossM wrote: However. You miss the point. You may very well assure me that you can control the knob and turn it off at 200b. Congratulations. But that does nothing to assure me that others do. As I tried to explain, I cannot tell if a cylinder has been overpressurised. Especially so if I do not know - or even if I knew - that someone was filling it from a 300b tank. ONLY filling it from a 200b tank will assure me it was never overpressurised _more than it's design pressure_.

And that is my point. 300 bar is within the designed safe pressure for a 200 bar cylinder. It's not it's working pressure, that is something different. So it matters little really.

Aside from that, you will never ever know. You can't even tell if the manufacturer tested your cylinder, and thus put 350 bar into it.

The temperature comment was because although you may fill at room temp, during filling or in other environments your 200 bar cylinder will be subjected to more.

Aside from all this, how many cylinders are on record as failing due to an over fill?

The only examples I have seen have failed at the gauge and have been 200 bar fills at 200 bar cylinders. The problem, which 200 bar never solves, was someone filling from about 20-30 bar direct from 200 with the tap opened way too quick. That last scenario will account for way more failures than a 300 bar slight over fill. But it's something filling only from 200 doesn't solve, yet is more dangerous, puts more stress on the tube, but you seem completely happy with that?

We'll have our revenge where it counts. World Championships Field Target 2013 held in NZ.