How much gas compared to wire

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I have used a wire feed with flux core before and now Im getting a mig.  Im not sure what size tank to get, an 80cf would be nice cause of its size but I dont want to run out every time im in the middle of a project so I was think a 125cf.   If you had to take a wild guess how many lbs of wire do you think you would get out of an 80cf ?    I know wire speed and everything will effect it but just a ruff estimate.    Thanks
Reply:If you use a 15 CFH flow rate, like I do, that's 15 cubic feet per hour, so a 125 CF tank would last for 8-1/3 hours of actual arc-on welding time.  AN 80 CF tank would last for 5-1/3 hours.
Reply:To get a comparison to wire you would need the deposition rate of what you are using. Much of this information is available from welding supply sources. Here is some from ESAB for .035 wire.400 ipm, 1016 cm/min  180  25  6.3 lbs./hr., 2.9 kg./hr.  450 ipm, 1143 cm/min  197  26  7.1 lbs./hr., 3.2 kg./hr.  500 ipm, 1270 cm/min  213  26  7.9 lbs./hr., 3.6 kg./hr.  550 ipm, 1397 cm/min  230  27  8.7 lbs./hr., 4 kg./hr.  You must also take into account the deposition efficiency which takes into account spatter loss etc. For GMAW the efficiency is VERY high for spray transfer and goes down as the spatter goes up. For SMAW this is calculated with stub loss.So figure how many lbs per hour you are using in wire and then how many cubic feet of gas per hour. I have a little program I wrote years ago that may help for comparing costs etc. The file can be downloaded at http://www.weldinginspectionsvcs.com...on_program.htm (You don't have to fill out the form, just go to the bottom of the page for the download link) . You have to fill in the data but it may be useful. Have a nice dayGeraldHave a nice dayhttp://www.weldingdata.com/
Reply:I'd suggest getting the largest cylinder that you can easily handle.  I've found that I can handle a 125CF pretty easily.  It also fits in the trunk of my car which makes it a bit more convenient to get filled without having to drive my truck around.I usually run 20-25CFH of C25.  I get porosity when I get as low as 15CFH.-Heath
Reply:What did you guys find out what is cheaper like for gas you have to buy/rent a bottle and then pay for gas + wire. I figured out it would be cheaper in the long run to run with mig (gas).
Reply:Flux core wire is pretty expensive, so it's definitely cheaper to run MIG with gas.  As for getting a cylinder cheaply, I try to pick up used cylinders cheaply.  125CF Oxygen cylinders are pretty common and a welding supply place will usually swap them straight up for a cylinder with any other kind of gas in it.  I've found that 40CF and 80CF cylinders are harder to come by as they're in greater demand among hobby welders.-Heath
Reply:Have you considered using C02? It has a bit more splatter but you can get shielding spray for that. A 20 lb. C02 cylinder is nice and low and will hold the equivalent of 160 cu. feet of compressed gas. .1234 lb liquified C02 = 1 cu. ft of gas. 1 lb liquified CO2 = 8 cu. ft of gas.20 lb liquified CO2 = 160 ft of gas. CO2 has excellent penetration and is good for hobby welders like myself who aren't hampered by welding specifications other than mere aesthetics. Other advantages are lower cost, presently about 50% of argon/CO2 at my local Airgas dealer. ($30 for 20 lb. CO2 versus $60-65 for 160 cu. ft argon/CO2) Of course, if you are welding aluminum or stainless with a spool gun you would also need argon, but for general mild steel welding, CO2 does it for me. I also like the fact that the valves are similar to Acetylene tanks - you can just crack the valve to start welding rather than having to open the valve fully several hard turns to initiate the top seal on the argon-type of tank. It's faster and easier on one's wrist. My 2 cents.Putting on my flame suit to protect against scorn and disrespect from the anti-CO2 cadre.   Last edited by gnm109; 05-27-2006 at 10:38 AM.
Reply:I'm a huge fan of CO2.  I have to have CO2 and argon and argon mixes available for everything I do, but I choose CO2 for most of my mild steel GMAW.  Thinner than 16-ga. gets the C-16 or C-25, though I CAN go to 24-ga. with CO2 if I really had to.
Reply:I too like c02 , when it's usable (most of the time ) last 50 pound bottle i got refilled was about $19- that's maybe  400 cubic feet. what they (the people who sell gasses) don't tell you, is that on cheap (oxygen ,nitrogen , c02 ) gasses , most of what you pay for is labor. that's why all( well  most )  my bottles are big ones . i am cheap(try to be ) and like to save money .
Reply:Gotta agree with Roy big time.  The biggest expense in filling the bottles is the hookup/unhookup labor for each bottle.  You will save significantly is you buy the biggest bottles you can afford and transport.  The vast majority of my bottles are 220CF and 50# (CO2).  They won't sell the 330CF bottles around here.  But I will admit, that the small bottles I also have are sure convenient at times, but I will always use the big ones whenever I can to save on filling costs.