Gas Refill Adapter?

Discussion in 'Fettling Forum' started by dday, Dec 26, 2009.

  1. dday

    dday Subscriber

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    Last edited by a moderator: Jul 1, 2015
  2. CWilkins

    CWilkins Subscriber

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    Hello,
    Is that really true that the LP only fills up the little cylinders half-way? I guess that would make sense as the fillup is relying on internal tank pressure to push out the liquid gas. I would think the same would follow through with the this e-bay adapter. Without a pump to push out the gas you are at the will of gas expansion and the pressure it creates.

    Chuck
     
  3. Wim

    Wim Subscriber

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    Maybe it would help if the "receiving" canister is put in ice? Just a thought.

    Regards,

    Wim
     
  4. dday

    dday Subscriber

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    Hi Chuck, I get the LP cylinders a little more than half full and thats all they take. As Wim pointed out I also tried sticking the empty cylinders in a freezer for a half hour or so before filling and might have got a bit more in them that way. I guess it would probably make sense then that it would probably be the same with butane. I was a little dissapointed with my $18 LP filler, so I'll probably stay away from this butane one :frown: . Thanks for your input Gents.
     
  5. G1gop

    G1gop United Kingdom Subscriber

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    Yep hot towels around the top one and put the bottom one in the fridge/freezer first.
    Works for me
    Alan
     
  6. Lance

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    Depends on how brave you are but there is a pressure release valve on your cylinder and if you push it to make it work then you can bleed off the Gas and get more fluid in.

    Takes guts and out-of-doors and no flame within 500 feet and three rabbits feet in your pocket, and two eyes of newt under you bonnet. And you will need three hummingbird tongues, 6 frogs ears, ten chicken lips, and 14 beaver feathers.

    Don't forget to toss it far and wide if the pressue release valve gets stuck open.

    lance
     
  7. RonPH

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    I would think that taken the necessary precautions, you should be fine and it should work. Just remember that the partly empty tank should be on the upright position and the tank with the liquid gas will be on the opposite position in order to get the liquid into the receiving tank as depicted in the picture. If it was the reverse, the empty tank will only get the gas (not the liquid) ahd would fill the tank quite quickly and if connected to the burner will only last a few minutes.

    Ron
     
  8. G1gop

    G1gop United Kingdom Subscriber

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    I used to work with gasses and we refilled small cylinders from big ones often. These were at many thousands of psi. You should treat ALL gasses with respect (just like all fuels). but if done carefully and outside (of course with a flammable gas!), then its it no more dangerous then refilling a cigarette lighter. After all thats the same principle.
    I usually put the empty in the fridge (or outside if its cold) and the full resovoir in the house nice and warm (near a radiator (if its not a naked flame etc!!) to warm up first. Then wrap the resovoir in a warm wet towel and go outside with them and refill. They will only refill until the pressure is equalised. So as the resovoir decresses in pressure, so does the amount you can piut in the other.
    Alan
     
  9. Jim Henderson

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    You can fill upto 100% but there is about a 10% leakage rate, so the cylinders must be checked and kept away from flame. Also if the cylinder is too full, they can leak when exposed to heat.

    There is a reverse schrader type valve on the shoulder of the cylinder that is pulled out, not in. You fill the tank while holding the valve open. When a lot of white mist comes out the tank is full enough. Needle nose or foreceps work on the valve.

    I have filled cylinders for decades this way. But like I said... 10% LEAKAGE.

    EXTREME CAUTION REQUIRED IF YOU TRY TO FILL WITH MY METHOD.

    CAVEAT EMPTOR.

    Jim Henderson
     
  10. hikin_jim

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    Jim,

    Are you talking about filling the green Coleman propane tanks?

    The little backpacking canisters don't have a valve on the "shoulder."

    HJ
     
  11. Jim Henderson

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    Propane ONLY, the big heavy steel ones including Coleman, about the size and weight of a steel short Stanley Thermos. These have the big(1 inch?) threaded adapter with a schrader valve inside and ALSO have the valve on the shoulder, this valve is a pressure relief valve.

    Butane or butane/propane mixes like Campingaz, Primus etc come in lightweight cans. Pure propane has too high pressure and can burst the "backpack" cans. DO NOT refill thin steel cans with propane. It is said you can refil these cans with BUTANE. Ihave not tried this.

    If there is confusion about what types of tank and gas are to be used, you should not refil until you know for sure. A mistake can be costly and/or fatal.

    Jim Henderson
     
  12. hikin_jim

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    Hi, Dan,

    Do you have a photo of the adapter you have now? And is the adapter you have now for the green heavy steel Coleman propane tanks or is it for the far smaller backpacking canisters?

    HJ
     
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  13. hikin_jim

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    Gotcha

    Good advice. I've pretty much come to the same conclusion. Even if the original backpacking canister came as a propane blend, I probably wouldn't try to refill with propane because of the high vapor pressure associated with propane.

    That's what I've been looking at. Still trying to figure that one out. The link that Dan posted is something I've looked at. I'm all ears to hear the experiences of others with equipment like that described in the link that Dan posted or other types.

    HJ
     
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  14. Jim Henderson

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    I have seen a few of these BUTANE refil adapters. It should be relatively safe since you would be using low pressure butane. Those "paint spray can" butane cartridges can be had very cheap especially at oriental grocery stores. Something like 3 for $4.

    I have never used one of these adapters but have been sorely tempted. Main gotcha is from my college thermodynamics class... Once the pressures in the two cans equalize, that is all the transfer you will get... P1V1=P2V2, Pressure, Volume

    SO I would suspect that at best you would get two half full cannisters after refilling the empty. Better than paying the cost of a new cartridge which I think is something like $5 for half a pound versus about $4 for several pounds of the cheap butane. But you have to weigh off the cost savings against needing twice the number of cartridges in your backpack. Also what do you do with all those half empty "paint" cans?

    Also, I believe the butane cartridges are pure butane so none of the advantages of butane/xxpropane mixes. Not that I ever noticed any big advantages of the mixed gases.

    I suppose if someone got clever and put in a pressure relief valve you could then refil a cartridge to almost full(best keep it to 80% or so). Just makes me nervous figuring out how to make a leak proof modification to a thinwall can.

    Just my thoughts,

    Jim Henderson
     
  15. dday

    dday Subscriber

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    Hi Guys,
    Thanks for your input as I do not have much experience with these isobutane stoves. I do have a few coleman stoves that use the powermax cartridges and got a good deal on several cases of the small and larger bottles. I also have a crux, but the cannisters aren't cheap, thats why I was thinking of this adaptor. I agree with your (Jim), Chucks and Alans thought that you would end up with two half full containers. That might be OK for someone that uses alot of gas, but for me it wouldn't be economical considering the $30+ price for the adaptor alone.

    HJ, sorry I don't have a pic of the propane adaptor, but its just the standard cheapie ($15?) brass adaptor for refilling strictly 16oz? propane tanks from a 20lb cylinder. I never tried warming the other tank :-k , I'll try that next. If I could get them to 90% like Jim does I would be a happy camper. I have one of those coleman grills that we take camping to cook burgers or steaks on and go through several 50% tanks each outing.

    Thanks again Guys for all your input. If anyone gets one, please report how it works. I see in his listing that he has several different styles available.
    Take care,
    Dan
     
  16. Jim Henderson

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    The 16oz propane tanks can be filled upto 100% by pulling the relief valve gently out to vent the air.

    When the air turns to white mist you are about80% and ENOUGH. When liquid sprays out you are 100% and a much greater risk of gas relase when the tank warms up.

    BTW, check the webpage bottom banner for that adapter. Lots of interesting stovie parts.


    JIm Henderson
     
  17. hikin_jim

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    Jim,

    With regard to P1V1=P2V2, wouldn't the fact that the cheap butane canister would be above the regular backpacking canister make some difference? Wouldn't more of the liquid go into the canister on the bottom and the gas in to the canister on top? In effect, you'd have one virtual canister with the liquid in the bottom canister and gas only in the top canister. True, you wouldn't be able to transfer 100% of the contents of the upper canister into the lower canister, but since the denser liquid flows to the lower canister, I would think the majority of the butane would be in the lower canister after filling, yes?

    As for the "spray can" butane canisters that are left over, there are adapters that one can buy that allow them to be used with backpacking stoves and lanterns. On occasions where weight and bulk is less of an issue (car camping, picnics, etc.), the "spray can" style butane canisters could be used. When weight and bulk are at issue (hiking, backpacking, etc.), then the refilled canisters could be used.

    With respect to butane vs. blended isobutane/propane, there really isn't much advantage at normal temperatures. In cooler weather (low 40's and below?), the isobutane/propane blends will perform far better.

    HJ
     
  18. RonPH

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    I would think that formula is correct as the pressure will just equalize between the two containers albeit the transfer of liquid gas would be more than sufficient to fill up the receiving tank before the gas pressure equalizes. Again the differences weightwise of the fuel will be more noticeable on the receiving tank using the valve being sold on Ebay. You could for comparison weigh the almost empty canister and the receiving canister before and after the filling.

    Ron
     
  19. redspeedster

    redspeedster United Kingdom Subscriber

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    Hi
    I know for a fact that you can 100% fill butane carts, in this example a small receiving cart can be fiiled completely with liquid butane and the connecting hose and the bottom (top really)of the donor too.

    I think you are right about pressure equalising, but as the cartridges are set one above the other gravity will do all the work for you. When you fill a lighter the instructions tell you to invert it.

     
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  20. RonPH

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    Hey Gary just like to know what adapters did you purchase in order to get the thing to work especially the connector on your bluett.

    Ron