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  1. #16
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    Quote Originally Posted by azzrock View Post
    how often does a oxy cylinder need to be tested?
    aaron
    You dont care(if you're talking about buy a cylinder from Speed Gass) you just change it over like swap and go. But 10 years I believe is the answer to your question..... but then, I might be out of date myself. lol

    Quote Originally Posted by azzrock View Post
    this is probably not a great idea but i often thought of filling a small oxy bottle from a larger
    doner bottle
    There was a guy around that did that sort of thing with argon cylinders. Emptying one full cylinder into 3 empty ones, getting about 87.5% of the gas out. You'd want to be careful... things would get hot and cold. There was a pump on ebay a while back for transferring the dregs of many cylinders into a full one........I controlled myself hehe

    Stuart

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  3. #17
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    Quote Originally Posted by Stustoys View Post
    There was a pump on ebay a while back for transferring the dregs of many cylinders into a full one........I controlled myself hehe

    Stuart
    But if you already have a full one why would you be putting more in it?



    Kind Regards... RC the comprehension nazi..
    Light red, the colour of choice for the discerning man.

  4. #18
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    Just had a word to the sole Queensland Speedigas agent, he's at Rosevale 4340.

    For argoshield light or whatever their equivalent is in an E cylinder, purchase price for a full bottle is $485 inc GST, swap overs are $173 inc GST

    At the moment through Supagas I'm paying $90?? for a refill and $198/year for bottle rent.

    If I use 5 bottles over 10 years, at current prices Speedigas will cost me $1177, Supagas will cost me $2430. Something to think about.

    Speedigas don't do oxygen yet but it is coming 'soon', pricing will be similar to Argon.

    I know the local council pays around $35 for an E size argoshield/oxy refill, don't know what their bottle rental arrangement is.

  5. #19
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    Quote Originally Posted by Stustoys View Post
    .... There was a guy around that did that sort of thing with argon cylinders. Emptying one full cylinder into 3 empty ones, getting about 87.5% of the gas out. You'd want to be careful... things would get hot and cold. There was a pump on ebay a while back for transferring the dregs of many cylinders into a full one........I controlled myself hehe Stuart
    That is me with the 3 G cylinders. Got them for free as the test dates have expired. I use them as cheap (no rent to be paid) storage vessels for Argon. Works perfectly well. There is no noticeable heating or the receiving cylinder or cooling of the donor cylinder - I guess the steel mass of a cylinder is just too big to take much notice. Also I do the transfer slowly, maybe over 10-20 minutes.
    Why I do this? When I have no larger welding project around, a hired cylinder lasts me 2 or 3 years between refills. I was sick of choosing between paying rent for an unused cylinder, or to return a 3/4 unused cylinder just to save rent. Now I have Argon always on tap, without having to pay rent.

    Argon is an inert gas, not much can go wrong really. I would be much more mindful with transferring Oxygen. A leak can be a dangerous source for ignition. But there is no reason with due care not to fill smaller cylinders from a large Oxygen bottle, as long as both cylinders are rated for the same pressure, and are rated to hold Oxygen, and the transfer is done outside, and you have the proper transfer line with fittings.

    The transfer of Acetylene at home is IMHO a no-no. In industry acetylene is filled into its cylinders in a water curtain (under a roof but open walls for ventilation and under running water sprinklers). It happens slowly to allow the gas time to dissolve in the Acetone. A much better idea would be to use a homebuilt Acetylene generator. Essentially a container is filled with Calcium Carbide granules, and water is let sprinkling over the granules in a controlled way. Very much like the good old carbide lanterns used on early bikes and cars. To get an idea, here a link to a Swiss maker of a welding Acetylene generator:
    http://www.gloor.ch/pdf/P122_en.pdf
    The upsides are the saving of the outrageous bottle hire cost, and the satisfaction of running your own gas factory (a bit like running a steam train is it?). And the availability of acetylene gas in very remote places. The downside is that such a gas generator needs to be prepared and charged before use, and cleaned/washed out after use. Just like a carbide lantern. Chris

    PS: here an Australian plan for a carbide generator... well, it is from 1945 but it gives an idea....
    http://trove.nla.gov.au/ndp/del/article/38568050

  6. #20
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    Hi Chris

    Quote Originally Posted by cba_melbourne View Post
    That is me.
    Well I wasn't naming names

    Quote Originally Posted by cba_melbourne View Post
    There is no noticeable heating or the receiving cylinder or cooling of the donor cylinder - I guess the steel mass of a cylinder is just too big to take much notice. Also I do the transfer slowly, maybe over 10-20 minutes.
    I should have said "could" not would. Part of it would be the gas would cool leaving one cylinder... then heat back up. I wonder just how cold a gas released from say 1500psi gets?

    How easy is Calcium Carbide to get?

    Hi Bob,

    Thanks for the prices. The closest Speed Gas to me it about 30 minutes drive away, the closest BOC is about 3 minutes away.
    BOC $190 a year for rent + $117 for gas (that's a 3 year old price for a cylinder swap)= $307(I'm pretty sure argoshield54 costs more than argoshield light). I still have the same bottle(I think.....maybe there was one change), $687 v $485


    Rents paid in advance right? Then I'm paid up until 1/15


    Are you still allowed inert gases in a station wagon?


    Stuart

  7. #21
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    Quote Originally Posted by Stustoys View Post

    How easy is Calcium Carbide to get?

    I do not know. The gas makers such as BOC and Supagas will certainly not sell it, for fear of ruining their business . Small quantities you can always buy from chemical suppliers, but probably far too expensive and you do not need high purity analytical grade stuff. Maybe some people visiting caves still use carbide lamps and have a supplier? I also did read somewhere that the stuff is used to ripen Bananas, maybe someone in the Bana trade can name a supplier? Calcium Carbide used to be sold by the Kilo in sealed tins - as long as the stuff is kept dry it is pretty safe.

  8. #22
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    Regularily used to transfer medical O2 into smaller cylinders where I worked.

    Never worried about how many smaller cylinders I could get from a larger one, wasnt directly paying for it, so didnt consider it.
    Was always careful about cracking cylinder slowly; suddenly one has full bottle pressure on their hands.

    We had an actual cylinder transfer setup. Nothing complex, could be rigged up without too much pf around. Smaller cylinders are easier to use and cart around when testing equipment. If you are gunna do your own transfers I would advise checking gas sealing. We used to use this stuff in a pink and white can, but soapy water works reasonably well.

    An important thing when dealing with O2 is use O'rings that are suitable. Standard ones that are made with an oil content -- I wouldnt use em. Sorry its been a while so am a bit rusty on info. Think the ones we used were Viton. Didnt use std white thread tape, we used the green stuff.
    www.lockwoodcanvas.com.au

    I will never be the person who has everything, not when someone keeps inventing so much cool new stuff to buy.

    From an early age my father taught me to wear welding gloves . "Its not to protect your hands son, its to put out the fire when u set yourself alight".

  9. #23
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    Quote Originally Posted by Stustoys View Post
    Hi Chris


    I should have said "could" not would. Part of it would be the gas would cool leaving one cylinder... then heat back up. I wonder just how cold a gas released from say 1500psi gets?
    Are you still allowed inert gases in a station wagon?
    Well, I can say that if one were to lose a full CO2 cylinder off the back of a truck on a Tasmanian winter's morning and said cylinder was to lose its valve and therefore its contents. The cylinder would still be frozen around 4 hours later. Don't ask me how I know this, um, I just do.
    As to the inert gas in a station wagon, fairly sure that is an emphatic no due to their asphyxiant properties. We're not even allowed an aerosol can in the cab at work for this reason.

  10. #24
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    Hi Karl,

    Sound "interesting" depending on just how far away you happened to be at the time.lol Though, isnt CO2 a liquid already?

    Quote Originally Posted by Karl Robbers View Post
    As to the inert gas in a station wagon, fairly sure that is an emphatic no due to their asphyxiant properties. We're not even allowed an aerosol can in the cab at work for this reason.
    Its a car not a pressurized plane!.... but sadly you're likely to be correct.

    Where is Simon.. just how much inert gas would I need to knock me off in a station wagon?

    Super Gas had a shitfit when a mate and I were going to lay down a 45kg LPG bottle in a ute. So we stood it up at the back of the ute and tied it in. I still think we would have been better off with it laying down if we'd run into a post.. Would I be right in guessing there is a pressure release in the valve that won't work venting liquid? Now I guess they have to worry about someone picking one up and heading off to the pub parking the car in the sun?

    Stuart

  11. #25
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    Quote Originally Posted by Karl Robbers View Post
    Well, I can say that if one were to lose a full CO2 cylinder off the back of a truck on a Tasmanian winter's morning and said cylinder was to lose its valve and therefore its contents. The cylinder would still be frozen around 4 hours later. Don't ask me how I know this, um, I just do.
    As to the inert gas in a station wagon, fairly sure that is an emphatic no due to their asphyxiant properties. We're not even allowed an aerosol can in the cab at work for this reason.
    Karl, I can assure you that transferring the contents of a full G size cylinder into an emty G size cylinder does NOT cause the donor cylinder to even feel cool, let alone freezing. Even the 6mm copper transfer pipe I use does NOT feel cold to the touch. At work I use lots of Nitrogen in G size cylinders, and I can tell you tat emptying one over a period of 20-30 minutes only causes some slight condensation on the regulator, and the cylinder itself may feel about 10 degrees cooler than ambient temperature. I have no experience with CO2 myself, but I think it is stored as a liquid, and releasing it causes the liquid to evaporate. Evaporation requires energy which is taken from the surroundings and it is this effect that causes intense cooling.

    As for transporting an inert gas cylinder like Argon or Helium inside a car, I agree this is a nono if the car is your workplace and you must comply to OHS rules. Argon is colorless and odorless and heavier than air and certaily an asphixation risk in an enclosed area. But like with so many things, as a private individual you can do what you like, it is up to you to take responsibility for your own safety and do your own risk assessment. I personally think it is far more dangerous to use a ladder to clean out your gutter, than to transport an Argon cylinder on the back seat. The risk of the cylinder leaking is minimal. I do leave a window open for peace of mind. But I think the fuel jerrican in the boot is actually more of a hazard to my life than the Argon cylinder. Chris

  12. #26
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    Quote Originally Posted by cba_melbourne View Post
    s only causes some slight condensation on the regulator, and the cylinder itself may feel about 10 degrees cooler than ambient temperature. I have no experience with CO2 myself, but I think it is stored as a liquid, and releasing it causes the liquid to evaporate. Evaporation requires energy which is taken from the surroundings and it is this effect that causes intense cooling.
    the refrigeration effect takes place at the point of expansion..ie the regulator. The temp drop is dependant upon amount of vapour ( volume) that is expanding..remove the reg and open valve and you will see ice forming on the valve...providing you have enough nitro

  13. #27
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    Default decanting

    hi all i was only thinking of decanting oxy and argon.
    as far as the cooling affect eskimo i wasn't planing on using a
    regulator for decanting.
    I thought the the cooling effect was due to the first gas law
    pressure and temp are all ways related.
    maybe i should google that befor posting. maybe
    aaron

  14. #28
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    I did some research while at work yesterday. This was related to work stuff, but just for interest sake.

    Most of the gases mentioned in this thread, I believe come under the heading of "Ideal Gases". All ideal gases follow Boyle's law. Or all gases that follow Boyle's law are "Ideal Gases".

    This law states that the volume of an ideal gas is inversely proportional to its pressure. Apparently all ideal gases have the same volume at a set pressure. One kilogram of CO2 has a volume of about 500 litres at atmospheric pressure.

    LPG is not an ideal gas. Its volume is related to its temperature and pressure. It will stabalise to ambient temperature.

    CO2 is a liquid within a narrow range of pressures. When the valve is knocked off, some of it will turn to gas, but this will cause a large drop in temp which meant that the CO2 in the cylinder was very cold, dry ice and so would have taken a long time to sublimate and dissipate. Dry ice can last for a long time. Sublimation temperature is around -75 degrees C.

    The reason I was killing time with this research is that we were once told during a forklift refresher course that the volume of gas in the cylinder will not affect the pressure and therefore the filling/emptying of the cylinder, but when filling SO2 (Sulphur Dioxide) containers from a cylinder, the process gets very slow when the cylinder is nearly empty.

    I wanted to work out what the difference was. Now I know.

    Dean

  15. #29
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    Quote Originally Posted by bob ward View Post
    I know the local council pays around $35 for an E size argoshield/oxy refill, don't know what their bottle rental arrangement is.
    Minor correction. Current local council E size BOC oxygen refill is $29.12 inc GST - compare that to the retail customer price of $89 inc GST

  16. #30
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    Default Bunnings at Mile End

    Noticed yesterday that Bunnings now have Core Gas oxy and acet cylinders .

    $200 each cylinder deposit but no rental D size
    Plus gas
    Oxy $70.00
    Acet $100.00


    BOC ( June 2015)

    $32 monthly rental for oxy and acet cylinder

    $136 for oxy and acet gas
    this makes bunnings more expensive for the gas but overall costs may still be cheaper for those who do not use the gas within say a 12-13month period.

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