how much pressure

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I think I got shorted on my Oxy tank.  Fresh from the shop it's 1500 psi.  I was thinking it should be closer to 2500 psi.Did I get shorted or am I having a brain fart?  To tell the truth, I never paid much attention to the high side but had occasion to hook my regulator up to someone elses tank to check my gauge and I seem to recall it reading alot more than 1500 on a new tank.david
Reply:The one's i get run about 22 00 to about 2500 never had one that low!!
Reply:Take it  back & get one that is full. The supplier ought to swap it out unless you've had it for a couple of days.
Reply:Plain and simple you got screwed!Ron ShopFloorTalk Millermatic 350P, M-25, M-40 gunsDynasty 300DX, Coolmate 3, Crafter CS-310 TorchTrailblazer 302, 12RC, WC-2430A spoolgunSpectrum 2050Thermal Arc Plasma Welder PS-3000/WC-100B
Reply:avg reading full is 2200
Reply:An O2 tank that is properly filled should show 2200psi at 70 degrees temperature.  Readings slightly higher or lower are normal  at temperatures above or below 70 degrees.One of 2 things has occurred; Either the valve on that cylinder is leaking, or it's an old cylinder that has been derated and was only filled to 1500psi.  Some gas distributors are, shall we say, sneaky basturds who run a lot of 1500 psi loads out the door to customers they figure won't check.Appreciation Gains You Recognition-
Reply:Interesting point Franz.  What determines if it's derated?  It's about as old as you   but has a very recent hydro date on it.  I think the original date on it was 1953.  I don't think the welding shop is screwing me, but their supplier may be.I think I'll be buying a CGA 540 nipple, nut and oxy gauge for the next trip to the supplier.
Reply:Honestly, I don't know when a cylinder has to be "derated" and quite frankly, I think the derating of cylinders for welding gasses is a crock of HORSESH!T that some suppliers are using to screw the customer.There are 2 plants here that refill cylinders, and I've seen with my own eyes that one of them fills a compeditor's cylinders for them, and oddly, the ones with the refill capability are the used oat merchants telling their customers the derated cylinder story.I probably own in the neighborhood of 20 cylinders, and have never had one that was "derated".  I have had cylinders that came to me with bad valves, and they were definitely underfull when they slid across the dock.  The guy who unhooks the cylinder from the manifold at the fill plant is supposed to check the valve after unhooking and before screwing the bell on, but I doubt they do.One thing that has interested me for a while is that Co2 cylinders have a brass cap for the valve, but the caps don't seem to be available for oxygen cylinders.Appreciation Gains You Recognition-
Reply:From what I understand the cylinders get de-rated when the hydro test is done.  I guess the cylinder isn't safe at the higher pressure so down it goes.  In stead of shafting customers they aught to de-rate them for CO2 cylinders and make use of them that way.
Reply:Don't believe the derated horse**** you are being fed.  A cylinder that does not pass hydro that means it split/exploded and has a f***ing hole in it or is in peices.  Oxygen, argon, nitrogen etc. are hydrotested at 4500 psig.   If they fail they blow.  Seen two do it.  The first time I needed new underwear.Acetylene due to that they are low pressure tanks and filled with diatomeaous earth and acetone are never hydro'd.  SCUBA and SCBA tanks witch have a working pressure of 4500 psig are tested at 9000 psig.Hydro testing cylinders involves removing the valve filling the cylinder with water.  Then the testing valve and hose are attached.  During the test the cylinder is submerged in a tank filled with water.  Our tank was 1" HY100 steel and acted as a scatter sheild.  When they are test the pressure is brought up to and maintained at 4500 psi for 30 minutes (USN procedure).Last edited by Shade Tree Welder; 05-29-2004 at 11:56 AM.Ron ShopFloorTalk Millermatic 350P, M-25, M-40 gunsDynasty 300DX, Coolmate 3, Crafter CS-310 TorchTrailblazer 302, 12RC, WC-2430A spoolgunSpectrum 2050Thermal Arc Plasma Welder PS-3000/WC-100B
Reply:After lugging an actelyne tank home, dragging it to the back of my shop and hooking it up to find it empty (I noticed that they were not astounded to see this, but rather, "Oh, another one??"), I now ask the shop to put a gauge on it and let me see how full it is.  They seem to understand, and I notice they have a number of gauges lying there to do just that.  I wouldn't bother hauling the tank back, but I'd tell the shop. and say when you do bring it back they owe you a freebie- a good shop will.At the Lake
Reply:I don't know when a cylinder has to be "derated"
Reply:Thanks for all the info guys.  Very informative.I'll probably mention it to the welding shop so they know they may have a problem with their supplier.  I don't think I'll be asking for anything as I feel like they gave me a pretty good deal when I upgraded my little tanks to 125s.
Reply:Is the +10% for filling them without cooling?  And then when they cool, they would drop back down to normal full pressure?Or is it for being 10% overfull for delivery to customer?
Reply:Is the +10% for filling them without cooling? And then when they cool, they would drop back down to normal full pressure?
Reply:Around here anyway - if your cylinder fails hydro  - its returned with either a hole drilled in it or the valve is removed and the threads have received the chisel treatment.  Those are the only options.Here in the Great White NorthMosquitoes can't fly at 40 below
Reply:Snidley,Most places I've seen here (Southern California) have an understanding with the customer.  We buy the tanks from them and COULD exchange them anywhere we damn well please but take them back to the seller for refill (actually exchange).  In consideration for this business, they assume responsibility for the costs of hydro testing.