mig and flux core tips and techniques, equipment, filler metal
Does a gas mix like C-75 which is 75% Argon and 25% CO2 separate in long-term storage? I have a large gas bottle that lasts a year or two and on days when I think I don't really know how to weld, I wonder if something has changed the gas mixture so I get straigt Argon? What do y'all say??
- Otto Nobedder
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(This reply is duplicated on the TIG forum.)
You would think so, but no, not really. The molecular motion (heat) that keeps it a gas keeps it pretty well diffused. CO2 is heavier than Ar, of course, so there is a variation in the ratio between the top and bottom of the cylinder, but as soon as you begin drawing gas, you begin mixing the contents of the bottle.
Consider the manufacture of these gasses. Air is cooled in stages to the liquid state of each gas to get them to condense in a fractional distillation column. This is a very energy-intensive process, yet is far more efficient than separating them by weight in a centrifuge.
I've been welding almost 30 years, and I still have off days. Some days a pipe weld looks like a "wedding band", some days more like an ugly divorce.
Steve
You would think so, but no, not really. The molecular motion (heat) that keeps it a gas keeps it pretty well diffused. CO2 is heavier than Ar, of course, so there is a variation in the ratio between the top and bottom of the cylinder, but as soon as you begin drawing gas, you begin mixing the contents of the bottle.
Consider the manufacture of these gasses. Air is cooled in stages to the liquid state of each gas to get them to condense in a fractional distillation column. This is a very energy-intensive process, yet is far more efficient than separating them by weight in a centrifuge.
I've been welding almost 30 years, and I still have off days. Some days a pipe weld looks like a "wedding band", some days more like an ugly divorce.
Steve
- Otto Nobedder
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If your bottle has been idle long enough for you to suspect separation, then, yes, it's possible.
We all have off days.
Steve
We all have off days.
Steve
kermdawg
- kermdawg
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I read somewhere on these forums a good tip, it applied to mig gas, co2 and whatever the mix is (you can see how much i mig lol)
But disconnect the cylinder and spin it around slowly a couple times, like the guys do at the gas store when their walkin it out to your truck. Thatll mix up the gas again for ya. Dont wanna shake it or anything like that. Just gently walk it around the shop a little.
Mixed gas will seperate if its left idle long enough.
But disconnect the cylinder and spin it around slowly a couple times, like the guys do at the gas store when their walkin it out to your truck. Thatll mix up the gas again for ya. Dont wanna shake it or anything like that. Just gently walk it around the shop a little.
Mixed gas will seperate if its left idle long enough.
Signature? Who needs a F***ing signature?
Otto is right. The diffusion of the gases caused by the molecular motion and the "desire" to become completely mixed (called entropy) assures that the gases remain mixed.
Perpetual stick/TIG welding student (or master of molten metal massacre)
Miller XMT304
- Otto Nobedder
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Tell the Marine Corps to secure a building, and they will toss grenades and storm the building immediately.
Tell the Army to secure a building, they will surround the structure, lay seige, and negotiate a surrender.
Tell the Air Force to secure a building, they'll get a five-year lease and have air conditioning installed.
Steve
Tell the Army to secure a building, they will surround the structure, lay seige, and negotiate a surrender.
Tell the Air Force to secure a building, they'll get a five-year lease and have air conditioning installed.
Steve
Last edited by Otto Nobedder on Sat Aug 13, 2011 1:11 pm, edited 1 time in total.
Now that's funny right there, I don't care who you are.
Jim
Pipefitter/Weldor out of Local 396
Millermatic 252
Dynasty 200DX
Maxstar 150 STL
Spoolmate 100
Hypertherm Powermax 85
Miller Digital Elite
JD2 Model 32 Bender
Emerson 7120 Horizontal/Vertical Bandsaw
Oxy-Gas Torch outfit
Generac XP8000E Generator
Pipefitter/Weldor out of Local 396
Millermatic 252
Dynasty 200DX
Maxstar 150 STL
Spoolmate 100
Hypertherm Powermax 85
Miller Digital Elite
JD2 Model 32 Bender
Emerson 7120 Horizontal/Vertical Bandsaw
Oxy-Gas Torch outfit
Generac XP8000E Generator
- Otto Nobedder
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Some time in the next week or two, I'll post some pictures of the "cold box" I'm building for the Hemlock semiconductor plant in Clarksville, TN. I don't know how the hell they're going to ship it. Probably two 38-wheel crawlers, 7 MPH all the way. That'll give me a week off, since I'm supposed to stay here 'til it's done, and be there when it arrives.
Steve
Steve
TheExpert
- TheExpert
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In chemistry and chemical engineering, a separation process, or simply a separation, is any mass transfer process used to convert a mixture of substances into two or more distinct product mixtures, at least one of which is enriched in one or more of the mixture's constituents. In some cases, a separation may fully divide the mixture into its pure constituents.
Ultralow787
- Ultralow787
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I don't know about the separation of the mixed gases once they are in the cylinder, but the explanations about molecular activity keeping the mixtures in suspension make sense to me! I did hear from some reliable experts at Lincoln Electric, that gas suppliers can and do miss-mix gases on occasion at the filling stations. The result is that a welding set-up or process that normally works well, all of a sudden goes in the toilet when a new bottle of gas is installed. I'm sure it does not happen often, but everything is possible. What do you all think?
Perfection is impossible, but if you strive for perfection, excellence is obtainable!
1983 Canox "Sparkler" 225 AC Stick Welder
Hobart 210 MVP MIG Welder
Harris "Spitfire" Oxy-Acetylene Set
1983 Canox "Sparkler" 225 AC Stick Welder
Hobart 210 MVP MIG Welder
Harris "Spitfire" Oxy-Acetylene Set
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