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Up Topic Welding Industry / General Welding Discussion / gas cylinders
- - By piperdolan (*) Date 03-20-2008 13:57
Curios to a comment made to me that mixed gas cylinders, when sitting for along period of time need to be rolled on the floor to help re establish mix. Is there any mixed gas combination that would require this? I would guess there is no brake down of the gasses once mixed.
Parent - - By MDG Custom Weld (***) Date 03-20-2008 17:01
I have heard that some He mixtures can separate when they are stored for long periods of time (6mo or more), but I can't say I've ever seen it.
Parent - - By gshuma (**) Date 03-20-2008 17:22
The new guys are always told that they have to "mix up" the gas for 15 minutes or so before welding. The easiest way to do that is to roll the tank back and forth across the parking lot.
Parent - - By James Corbin (**) Date 03-20-2008 22:07 Edited 07-08-2008 21:10
[deleted]
Parent - - By gshuma (**) Date 03-21-2008 01:36
OK guys
I believe you but I'm still gonna tell the new guys that they have to "mix up" their gas.
Parent - By RioCampo (***) Date 03-21-2008 01:45
I'd like to see the rookie's try and mix that.
Parent - - By DaveBoyer (*****) Date 03-21-2008 03:53
Sometimes it takes Me a few years to use a cylinder of C25, but I can't say I have ever noticed a seperation.
It is a good thing the earth is rotating, otherwise the oxygen might seperate from the nitrogen in the atmosphere :-)
Parent - - By piperdolan (*) Date 03-21-2008 11:22
love this comment. Maybe this is a technical question, but why would the gas seperate once mixed
Parent - - By DaveBoyer (*****) Date 03-22-2008 03:01
I think it would be dificult to seperate them, but if anyone knows an easy way to seperate mixed gasses, let Me know, and maybee I can get the flatulance out of My breathing air.
Parent - - By James Corbin (**) Date 03-22-2008 05:53
[deleted]
Parent - - By Northweldor (***) Date 03-22-2008 16:34
As I recall, we had a thread like this several years ago in answer to a question I had about C25 used in low temperature conditions. It is my impression that we concluded that separation could occur depending on the dewpoints or vapor pressure of the gases, but I can't find the thread to verify this. This had to do with the CO2 condensing out and the argon being used, thus spoiling the mixture.

Would rolling a cylinder under high pressure actually remix gases? (I can see some physics operating with a Co2 cylinder where a liquid gas is involved, but wouldn't separated gases behave like a liquid and simply return to their respective positions when the cylinder is upright again?).
Parent - By makeithot (***) Date 03-27-2008 00:34
gases when mixed all act as if that gas was alone in said mixture I am in need of some gas physic review right now as we speak and will have to go look it up, but the genral gas law,daltons law, and charles law explain what occours when gases are mixed. do they seperate when mixed in a high pressure cylinder I have to say no to that. Rolling that tank across the parking lot or shop to pre-mix before use is a good one and am going to put that to use first thing tomorrow.
Parent - - By Sourdough (****) Date 03-22-2008 19:13
Here we go fellers........hot air rises.
Parent - - By Northweldor (***) Date 03-22-2008 19:59
Sourdough:
If you are not interested why don't you just skip it, as I do when you get carried away? Why is the snide remark necessary?
Parent - By piperdolan (*) Date 03-26-2008 18:16
thanks for your comments.
Parent - - By smokey36 Date 03-26-2008 23:29
so i guess everything sourdough says rises to the ionesphere.........
Parent - - By Sourdough (****) Date 03-27-2008 15:11
You know, time after time i get these guys that get so butt hurt by what I say on this forum. If you can't take the heat get out of the kitchen..........nuff said.
Parent - By Northweldor (***) Date 03-28-2008 12:03
Sourdough:

"...time after time..."  ?? This would lead most people to examine what they write and the way they express themselves.

   "An unexamined life is not worth living."

                                                       Socrates
Up Topic Welding Industry / General Welding Discussion / gas cylinders

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