bottle of Argon leaking or ?

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OK, I'm still very new to welding so am not sure:just got a 20l refill bottle of Argon and screwed the regulator on and left thebottle in the corner (I'm cleaning up and won't be doing any practice welding for a few days). Being new to all this, I'm also checking everything maybe more than one would normally do.With the valve on the bottle closed and the valve which allows argon to the welder closed, I've been eying the incoming gauge for a few days - it moved down ever so slowly (a hairline - I know because it was on a line before and now it's below - yes I was looking at it square on  ).I have brushed some dish-washing liquid/water on all places where it could leak (except for the bottle itself) and found nothing. The weather has cooled down a bitthe last couple of days - does this make any difference. Is this all normal or what  Don't tell me that argon escapes if you don't use it quickly
Reply:If the valve on the bottle is closed, don't sweat the small stuff. You have a minor leak, very minor. Just remember to close the valve when you aren't welding.Lincoln PrecisionTig 275Miller 251Miller DialArc 250Bridgeport millHossfeld bender & diesLogan shaperJet 14 X 40 latheSouth Bend 9" 'C'Hypertherm 900Ellis 3000 band saw21"Royersford ExcelsiorTwo shops, still too many tools.
Reply:I disagree with the previous post;  I don't think you have a leak.  I think you've just had an introduction to Charles' Law of gas pressures.  As you somewhat suspected, temperature DOES have an effect on pressure and volume in a closed cylinder.  As your temperature cools, you will notice a decrease in your pressure.  I used to fill my own SCUBA and SCOTT-Air-PAK SCBA bottles and can tell you that a "hot fill" (the bottle was filled quickly without being placed in a tank of cool water) will get hot and it will have less indicated pressure when it cools down.  That's why your gauge might read 2200 when the LWS unhooks it from the bank of cylinders, but when you get it home, it's 2150.As you said, it's been cool lately and your pressure is only a "hair" lower.  I think when it warms back up, you'll see the needle move back up a hair.Lincoln AC225 & MigPak 140, Lincoln Magnum SpoolGun, Miller Spectrum 375-X Plasma, Syncrowave 200 TIG, Millermatic 252 MIG, Miller Digital Elite, General 7x12" horiz/vert bandsaw, 3' box/pan brake, 20 ton press, milling machine, 12x28 lathe, etc.
Reply:Also, just to further rule out any tiny leaks, make sure you have PTFE (Teflon) tape on the threads of all your fittings.  I had a regulator that without Teflon tape, you could almost WATCH the pressure gauge dropping.  Lincoln AC225 & MigPak 140, Lincoln Magnum SpoolGun, Miller Spectrum 375-X Plasma, Syncrowave 200 TIG, Millermatic 252 MIG, Miller Digital Elite, General 7x12" horiz/vert bandsaw, 3' box/pan brake, 20 ton press, milling machine, 12x28 lathe, etc.
Reply:Originally Posted by AquafireAlso, just to further rule out any tiny leaks, make sure you have PTFE (Teflon) tape on the threads of all your fittings.  I had a regulator that without Teflon tape, you could almost WATCH the pressure gauge dropping.
Reply:why is teflon tape being used???????????welding fittings are a tapered compression fittong made of brass. if teflon tape is beong used there are problems with the fittings and they need to be changed out. if this is being done on oxygen and acetylene fittings that is commiting sucide. leaking fittings are extremely dangerous. if an inert gas is leaking and it fills a space and someone walks in and breathes it they are instantly DEAD. lack of oxygen or breathable air dispalced by inert gas is DEADLY. using a soap and water solution to check for leaks is perfect. when the leak is dected shut the system down and see why the leak is happening at that particular. the rubber that hoses are made from has a life, as they age they get brittle and will leak ever so slightly. a lot of times will take quite a bit of testing and sometimes will not be detected. if the hoses are over 10y/o and there is a question then remove them and cut the brass fittings off and that them to a welding supply and have a new hose made or a hose supplier and have them hook up the fittings and test them and if they leak have them replaced/
Reply:Argon in  bottle? Attached ImagesLast edited by Fat Bastard; 10-10-2011 at 04:55 PM.
Reply:Uhm, the OP said the bottle was closed.  And the valve to the welder is 'closed' (either the solenoid or the flow/pressure), he has a very slow leak passed the valve to welder.  Big deal.  In fact, because the needle is moving oh so slowly, one can safely say that everything is OK.  If I don't see the needle (low pressure side) move in 15 minutes, I assume everything is OK.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Originally Posted by con_fuse9Uhm, the OP said the bottle was closed.  And the valve to the welder is 'closed' (either the solenoid or the flow/pressure), he has a very slow leak passed the valve to welder.  Big deal.  In fact, because the needle is moving oh so slowly, one can safely say that everything is OK.  If I don't see the needle (low pressure side) move in 15 minutes, I assume everything is OK.
Reply:I think I'm in agreement with con_fuse on this one.  If the bottle is closed then the gauge is showing residual pressure (just whats in the fittings between the bottle and regulator).  If it takes a few days for that to bleed off then there is no problem worth worrying about.My name's not Jim....
Reply:Originally Posted by BoostinjdmIf the bottle is closed then the gauge is showing residual pressure (just whats in the fittings between the bottle and regulator).
Reply:Originally Posted by AquafirePTFE tape is not required on the straight threads at the tank connection (though it can't hurt) but it is needed on the tapered threads of the regulator/flowmeter and where it connects to the machine.  As I said, I was losing gas without it on a previous MIG (which was brand new with new fittings).
Reply:Thanks for all the feedback !I'm buying the gas, so I guess that's why I jumped to ask the question before considering (as was very nicely pointed out - at which point I was a bit ashamed of my question  ) that I'm looking at the pressure between the closed valve on the tank and the regulator. But reconsidering, I don't think it is such a "stupid" question and  I would like to pose a few more questions and confirm some issues so that I have sufficient knowledge in this area for the future - sorry if this is so basic for you guys( also, I will remember to consider temperature impacts on pressure in the future).The regulator is the same brand (GCE) and looks something like this (gauges just look different):http://www.ram-rijeka.com/off/337/of...-Rijeka.wshtmlQuestions:(a)The valve on the top of the argon tank (20l) uses teflon on the threads (teflon clearly visible) - is this normal or not (can't remember the one I gave in to be replaced (it was my first tank and I didn't think about it  )?  - since you guys were mentioning the teflon.(b)If there was a leak, I would have found it with dishwashing-liquid/soap & water - right ? - because I found no leaks on top of the tank valve "handle", where the tank valve comes out of the tank, tank/regulator connection, regulator outgoing connection or the valves on the regulator(c)The regulator is attached to the valve on the tank via the short extension which has a seal of some sort of plastic on the end of it which mates to the tank valve and seals via compression - I guess this just requires sufficient tightening and no teflon. The rubber hose from theregulator to the TIG welder has a similar type of connection with rubber o-rings - so I don't think any teflon goes there either ?(d)What is the best practice to ensure least loss of gas when not in use - close just the valve on tankor do you do more - close outgoing valve on regulator ? and always keep line to welder connectedLast edited by vjeko; 10-11-2011 at 08:34 AM.
Reply:Originally Posted by KelvinMiller told me just the opposite a few years back – no teflon tape anywhere.My understanding is that it can impede seating of the compression fittings, and, if it gets into the works, can clog stuff up and contaminate the gas/tungsten/weld.
Reply:Originally Posted by vjekoThanks for all the feedback !Questions:(a)The valve on the top of the argon tank (20l) uses teflon on the threads (teflon clearly visible) - is this normal or not (can't remember the one I gave in to be replaced (it was my first tank and I didn't think about it  )?  - since you guys were mentioning the teflon.(b)If there was a leak, I would have found it with dishwashing-liquid/soap & water - right ? - because I found no leaks on top of the tank valve "handle", where the tank valve comes out of the tank, tank/regulator connection, regulator outgoing connection or the valves on the regulator(c)The regulator is attached to the valve on the tank via the short extension which has a seal of some sort of plastic on the end of it which mates to the tank valve and seals via compression - I guess this just requires sufficient tightening and no teflon. The rubber hose from theregulator to the TIG welder has a similar type of connection with rubber o-rings - so I don't think any teflon goes there either ?(d)What is the best practice to ensure least loss of gas when not in use - close just the valve on tankor do you do more - close outgoing valve on regulator ? and always keep line to welder connected
Reply:There is teflon and there is teflon.
Reply:usually teflon tape IS used on PIPE threads ,NOT on compression or mated/flanged type fittingsidealarc 250/250 ac-dc tigidealarc 250/250 ac-dc tig #2 used for sticklincoln sp100hh125dual arbor grinder polisher30 yrs of hand tools52 pitch blocks 6p-26prake gauge -pitch gaugeG&D prop repair 918-207-6938Hulbert,okla 74441
Reply:Prop-doctor is right. Use the teflon on tapered pipe threads only. Also, be sure to use the tape correctly, so it can't get loose inside the system. Here's a link with good pictures: http://www.headballoons.com/Maintenance.htmlIan TannerKawasaki KX450 and many other fine tools
Reply:hi,just as a reminder that I was told that with argon you must open valve fully when using or it will leak at tank  valve.
Reply:Originally Posted by BD1hi,just as a reminder that I was told that with argon you must open valve fully when using or it will  [ Edit: possibly could] leak at tank  valve.
Reply:I have argon and o/a bottles of white teflon tape between the valve and the bottle and I wondered also because I have heard that it cannot be used, it looks like it may be a heavier gauge, the tanks are Liquid Air, Edmonton.Whats the story?Also look how the bourdon tube is made and connected to the needle, if it stays it may be nothing more than mechanical deviation, don't think they are their to read pressure that accurately, if it keeps moving well then you worry.
Reply:Re Teflon tape:Teflon on the valve on top of the cylinder is fine, we use it all the time.  No teflon anywhere else, as these fittings are designed to seal without tape.  You have a CGA 580 on the tank valve, and a pair of CGA 032 on the outlet of the flowmeter/reg and the inlet of the feeder.  See below for the small fitting designations.http://www.westernenterprises.com/en.../PDFS/wi13.pdf
Reply:Originally Posted by AquafireI re-read Vjeko's post and I think you're right.  He's not talking about the pressure in the bottle if he has the tank valve closed. He just hasn't purged the line and is watching the pressure bleed down on that minute volume of gas. Vjeko: the fact that it takes that long to lose a grasshopper's burp of gas tells you you have no leak in the connections. Who said anything about Oxygen?!?!  This is argon! PTFE tape is not required on the straight threads at the tank connection (though it can't hurt) but it is needed on the tapered threads of the regulator/flowmeter and where it connects to the machine.  As I said, I was losing gas without it on a previous MIG (which was brand new with new fittings).