I know this topic has been beaten to death and beyond, but something occurs to me that is perhaps too obvious for normal people to notice. If shooter safety is the goal not manufacturer revenue, it doesn't matter when the cylinder is manufactured. What matters is when it begins its life-cycle of rapid compression / gradual decompression.
What ISSF should have provided for (which would, incidentally, have given robinhoods something less to complain about) is some sort of recognized marking applied at the first retail sale. It could be a rollmark, perhaps a sticker - with a mandatory reversion to date of manufacture if a sticker is altered or removed. Manufacturers could enclose one sticker with every new cylinder whether or not packaged with a pistol.
Or is this too obvious?
Cylinder dating
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I suggested something like this in one of robinhoods' threads but it seemed to go unnoticed. Thank you william. This post is at least slightly reassuring, that rational thought does crop up now and then. Stress cycling of aluminum tube is certainly something to be concerned about. Any machinist/engineer takes such things into account when designing anything which will see a lot of stress cycles. Bicycle handlebars are one common example; ride a lightweight set of racing bars a couple of years too long and it's very likely they'll snap in half just when you need them most, like during a finish sprint, or when you're bunny-hopping over a crashed fellow competitor in the road ahead. Unhappy results as you can imagine, and obviously the potential for serious injuries is there with cylinder failure under 250bar or higher pressure - mostly likely to fail while being filled to capacity, so the shooter's face is going to be nearby. Of course none of the reputable cylinder makers are going to make such borderline engineered tanks that they're likely to fail even after 20 years of normal-scheduled use, but some day they will fail, eventually. Might take 50 years or maybe 100, but the potential is there.
So I don't object to dating cylinders, and publishing test data on random samples forced to the point of failure would be enlightening, but this arbitrary 10 year ruling is absurd when it comes to the real world fact that a cylinder begins the countdown the moment it leaves the production line, and is unlikely to reach the consumer in less than 6 months and in some cases, as robinhoods example illustrates, several years. The cylinders he bought were completely un-stressed, so it would make perfect sense to apply some form of certified marking indicating date of purchase on his essentially new cylinders regardless of their different dates of manufacture.
So I don't object to dating cylinders, and publishing test data on random samples forced to the point of failure would be enlightening, but this arbitrary 10 year ruling is absurd when it comes to the real world fact that a cylinder begins the countdown the moment it leaves the production line, and is unlikely to reach the consumer in less than 6 months and in some cases, as robinhoods example illustrates, several years. The cylinders he bought were completely un-stressed, so it would make perfect sense to apply some form of certified marking indicating date of purchase on his essentially new cylinders regardless of their different dates of manufacture.
As a mechanical/manufacturing engineer I can say the only system I would be OK with is a date stamped on by the manufacturer and a 10 year expiry.
It can be engineered to last 20 years for the worst case user, so only the sixth sigma child gets a face full of aluminium shrapnel, everyone else has to pay a smidgeon more for the privilege of shooting a state of the art PCP air pistol - bad luck.
It can be engineered to last 20 years for the worst case user, so only the sixth sigma child gets a face full of aluminium shrapnel, everyone else has to pay a smidgeon more for the privilege of shooting a state of the art PCP air pistol - bad luck.
As a Manufacturing Enginer with a Pressure Vessel Welding Cert, I concurr with the 10 year time life. It isn't necessarily the pressure cycling that is injurious to the "tank". Corrosion is a big enemy of service life, and funny as it seems, cycling the tank seems to reduce corrosion in my experience. Also many other products in commercial use have hard time limits on their lives and we dont seem to mind about them... Helicopter Rotor Blades are a key example, you fly em so many hours or so many years, whick ever comes first.........
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Chris__Colorado
- Posts: 81
- Joined: Fri Aug 03, 2007 5:17 pm
- Location: Colorado
Here's an interesting data point for the discussion:
Purchased this year (2014), my "new" FWB Cylinder was manufactured in 1985!
It does have a laser engraved/etching "1/2011" with the FWB logo.
I'll get at almost 7 years of "ISSF Compliant" use out of it...and decades personnel use after.
I'll post a pic later tonight.
My original FWB Model 2 cylinders were manufactured in 1983, so at least the "new one" I purchased IS newer by about two years. I've had the old one apart and the interiors looks fine, and am debating whether I should conduct a visual inspection on the "new" cylinder.
Given that the "old" cylinders are spec'd at 250 bar for PCP use and generally (virtually always) see less than half that pressure with CO2, I'm comfortable using them.
I do know the cylinder histories and do conduct my own annual visual
inspections. The cylinders are not abused and in a low humidity environment.
These FWB steel cylinders react differently than aluminum does to stress cycling. So, I can understand the ISSF concern. I've also dived 50+ year old steel scuba tanks...but they do get hydrostatic testing when needed. It's all about risk analysis and management. Pressurized vessels can be very dangerous. The ISSF 10 year rule makes implementation very simple--even if many think that it is not necessarily the "best" solution, it is one that is simple to understand and execute---very important when seeking compliance. The unreliability of human behavior must be factored into any solution.
When you start looking at simple cost over time (excluding TVM) , $300 for a cylinder, over 10 years, is just $30 a year, and just $2.50 a month.
That's under a dime a day....easily generated by most by tossing loose change into an empty container and leaving it alone until until a new cylinder is needed.
Chris
Purchased this year (2014), my "new" FWB Cylinder was manufactured in 1985!
It does have a laser engraved/etching "1/2011" with the FWB logo.
I'll get at almost 7 years of "ISSF Compliant" use out of it...and decades personnel use after.
I'll post a pic later tonight.
My original FWB Model 2 cylinders were manufactured in 1983, so at least the "new one" I purchased IS newer by about two years. I've had the old one apart and the interiors looks fine, and am debating whether I should conduct a visual inspection on the "new" cylinder.
Given that the "old" cylinders are spec'd at 250 bar for PCP use and generally (virtually always) see less than half that pressure with CO2, I'm comfortable using them.
I do know the cylinder histories and do conduct my own annual visual
inspections. The cylinders are not abused and in a low humidity environment.
These FWB steel cylinders react differently than aluminum does to stress cycling. So, I can understand the ISSF concern. I've also dived 50+ year old steel scuba tanks...but they do get hydrostatic testing when needed. It's all about risk analysis and management. Pressurized vessels can be very dangerous. The ISSF 10 year rule makes implementation very simple--even if many think that it is not necessarily the "best" solution, it is one that is simple to understand and execute---very important when seeking compliance. The unreliability of human behavior must be factored into any solution.
When you start looking at simple cost over time (excluding TVM) , $300 for a cylinder, over 10 years, is just $30 a year, and just $2.50 a month.
That's under a dime a day....easily generated by most by tossing loose change into an empty container and leaving it alone until until a new cylinder is needed.
Chris
Scary.. Is it an aluminium cylinder?
The aluminium used for the cylinders is one which is very easy to machine. I haven't checked its data, but from my experience the aluminium which can be more easily machined is also the worst in terms of corrosion resistance.I have lots of aluminium apparatuses which work with high pressure in my lab at university. When it is corroded you get leaks ... So I am happy with stamps at the production.... May be not the FWB stamps!
The aluminium used for the cylinders is one which is very easy to machine. I haven't checked its data, but from my experience the aluminium which can be more easily machined is also the worst in terms of corrosion resistance.I have lots of aluminium apparatuses which work with high pressure in my lab at university. When it is corroded you get leaks ... So I am happy with stamps at the production.... May be not the FWB stamps!