COPPER MIG vs COPPER BRACE CO$T$ ???

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This might be an easy one for experienced welders,but not me! so I need some help to figure out some co$t$ :  1) MIG :Let`s say I`m gonna weld plenty 1/8" copper sheet most of it overlap joints.What`d be the aproximated consumption of 3/32" deoxidized Cu wire per hour,or per 20 ft bead length? And what about the Argon volume, any idea ? Like so many bottles or cubic ft for such length or hours of welding ? How long would the Tungsten last?2) O/A BRACE: this option would consider Harris O Phos copper rod. In this case the question is basically the same. Amounts of rod per any unit, be it weld time,bead length (one slow pass). And the same for Oxygen and Acetylene volumes per hour, or lenght of bead? Don`t need a very accurate measurement because I know there are some variables that may turn the balance either way, just an educated guess for the unexperienced. Thanks guys for any help with this. Baculus.
Reply:As to answering your question, I don't have a clue. However, if you will get a copy of Lincoln's "Procedure Handbook Of Arc Welding" it well answer this. Also any other question you can possibly have about arc welding.
Reply:I don't know what you are doing.  However, I just used some silver soft solder to solder some ends on a wire for a rail I was building.Soft solder might be a option.  Clean and flux the metal, place the solder between the sheets, between 200 to 500 degrees (depending on solder). I did a copper awning a few years ago, this techinque was described to me by a roofer.hope this helps
Reply:20 ft bead length? WOW!BTW it's braze not brace... typo?Tig is out-too slow. expensive gas.O/A is out-too slow and too much warpage and gas expense.MIG would be best for 20 foot welds but the big problem is shrinkage and warpage in a 20 foot weld. MIG has high heat input so warpage will be a big problem. Check the elongation rate on your wire. usually 2% per foot.The welding procedure would be very important, if possible at all. but i just do not see this job as a welding job. It is possible but you will have to do a test with the full size pieces. Tacked together first starting in the middle and working out towards the ends. Very iffy.This is really a job for rivets and clekos aircraft style.Better talk to a aircraft sheetmetal worker.I would consider a sheetmetal shop making a folded joint.it's for a roof??? expansion contraction issues.Last edited by Donald Branscom; 02-18-2008 at 12:57 PM.
Reply:Baculus -- This is how I would get the information you are asking for (very simplified due to not knowing your background in welding). Get some material and run a sample. I sometimes do it when bidding a job that is other than steel. You run one rod or one pound and then measure, from there it is simple multiplication. Shield gases are measured in cubic feet per hour or liters per hour. Find the cf/h or l/h needed (Lincoln should have that information) and divide the capacity of the bottle. You may have to do some conversions as Lincolns info may only be in cf/h. Bottle capacity is measured in cubic feet here in the states. Tungsten consumption cannot be determined for you because there are too many variables. Tungsten will last a long time for a very experienced hand, but for the less experienced it likely won't last as long. I have seen guys get 2 hours out of one sharpening on stainless. That's all you need to know to figure the info you want. On the O/A consumption I can't even hazard a guess, but I am thinking it is going to be high due to the amount of heat required. As was mentioned above warpage is likely to be a real problem. The silver solder I mentioned is in fact a jewelers solder specifically for use on copper when you want no seams showing. As with all silver solders it is a high temperature, high strength solder. I will try and find the information on it and get you a link to it, but it could be Wednesday or so before I have it. As Oldtimer mentioned above Lincoln's knowledgebase will have a lot of useful info as far as welding copper goes, even the type of tungsten you should use and the best shielding gas. I believe it is pure argon but I'm not positive on that and would have to look it up myself. I have done very little of it as there really isn't much call for it, and that is the main reason we can't tell you what you are asking. I do know that it tig welds well, provided it is the right type of copper. Some types cannot be welded at all, some are difficult, and others weld easily. You cannot tell one from another just by looking at them. I spent some time in Monterey, CA in 1987. I started my formal art training in Mississippi and graduated from Eastern New Mexico University. Very informal, hands on place. Other than human figure, classes were usually 6 to 12 students. I only did one metal sculpture the whole time, did all the rest in clay, wood and paper. Mostly clay because I had never worked with it before. Since graduating they have all been wood, metal, or a combination of the two.The difference between art and craft is the quality of the workmanship. I am an artist.