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COPPER TO ARMATURE WELD
NELSON -
Saturday, February 9, 2008 - 4:35pm
Hi fellows;  Nelson, You might try to
don thibodeaux -
Sunday, February 10, 2008 - 7:36pm
Nelson, You might try to revit copper to your armature, then weld copper to copper. Don T. » reply  Nelson, That is pretty thick
Gene Olson -
Monday, February 11, 2008 - 8:55am
Nelson, Someplace else on the site I posted a copper stainless weld pic of a joint that has been outside in MN for the past 10 yrs or so. The nice thing about copper and stainless is that they have almost the same thermal expansion rates. That thick of copper may crack on you if you don't preheat. Gene Olson » reply  3/16 is thick
raferguson -
Monday, February 11, 2008 - 8:40pm
I TIG weld quite a bit of copper, 0.040 inch thick, and usually have my machine set for 90 amps. With 3/16", you might need 400 amps or so, which I do not have access to. I don't think that a 250 amp TIG welder is going to be close to adequate, a 350 might work. Anyway, due to the massive heat requirements, you are likely to need to preheat. Brazing is lower temperature, so probably more practical. I would probably go for a copper or bronze armature, but I think that the suggestion that no armature is needed is a good one. Even if you need an armature to build it, you might not need it once it is complete. Richard http://www.fergusonsculpture.com » reply I'm not sure where it was
Gene Olson -
Monday, February 11, 2008 - 8:51pm
I'm not sure where it was set anymore. but we did 3/16 with my 300 amp machine. It was a long time ago. He may get by. Gene Olson » reply  This is a 30 ft high,and
NELSON -
Tuesday, February 12, 2008 - 9:21am
This is a 30 ft high,and about 2.5 ft diameter tree project.Although the client got the 3/16" Cu sheet,if I see too much trouble surely will have to ask him for thinner material(if I use what he has it`ll be a plus!).I do know I can make it no matter how high or thick,but it`s a matter of making it efficiently,so my labor costs,will not unforseenably shoot sky high and I go belly up.Preheating so I can TIG weld doesn`t sound like fun on such a high structure. Preferably I rather Mig weld and clean up spatter,but no option will be discarded at this point.Further analysis has to be made.How is Mig vertical welding on copper? and if I used stainless as armature,can it be MIG welded to Cu sheet?In regards to welding,I have welding to armature and welding the sheet at joints. This brings me to one big dilema:armature material.If I used mild steel,how long would it last outdoors before galvanic corrosion does its job? Would that sealed(welded) environment inside, be conducive to corrosion beyond some rust? I`m think about the oxygen limitation that shall take place inside. Won`t that hinder Fe oxidation from oxygen starving? I guess this worries me more than thermal expansion rates,for once it`s all assambled, I don,t believe it`ll be an issue to worry about.Cu armature might be a consideration,but gee...I`ve got check the cost `cause that`ll use up some pounds of Cu bar huh! And what about armature strength if I used Cu bar?Would a sound 1/2" Cu round bar structure be ok if I considered that option?Gene,you mention possible cracking.Do you think that if I heat forge(moderate temperature)the Cu sheet and MIG weld, it will crack? I guess that thickness poses risk on that matter,but got try working about this material we already have.Won`t the forge heat anneal the Cu releasing tensile strength as it softens?I know I`ll have to reharden later on to the extent I might.Main concerns:1)Cu thickness.2)Corrosion of armature.It just occured to me,if a made the structure with steel not stainless,and zinc flame spray it, then weld Cu sheet on? Guess: steel+Zn flame spray cost vs. stainless cost! Sounds too complicated? 3)Armature material vs weld to Cu sheet 4)Process to cut left over sheet to make ends meet and weld. I don`t want to end up with vertical and horizontal seam lines that`ll show like patches all over.So that brought me to hand plasma cutting.Rich I remember your telling me how messy plasma is.Why did they build such sofisticated cutting device? Another use?I ignore how this may work.Will I have to end up disc cutting the Cu sheet? As I ask before Rich,considering the scale of this project,I thought I`d better be aware of amount of Mig wire required if chosen.And last but not least the main question remains in my mind:5) considering the above, do I go MIG or TIG ? Construccion time is a big issue here, and everywhere! » reply lost post
Gene Olson -
Tuesday, February 12, 2008 - 10:40am
I wrote a long answer and the ether ate it. try sil bronze mig. Cu to Stainless copper has high coeff. of expansion going solid >> liquid and almost no tensile strength as it solidifies it will crack if the parts can't move easily. (or are preheated and you don't want to do that if you don't have to on a piece that big. I don't think you could keep it hot, and if you did, you would be grilled.) Sil bronze on the other hand has no preheat in the spec. Test weld some pieces in a frame so they can't move. I think you can mig the cu together. If it works for you, sell the client of bronze "accents" and feature the welds. Gene Olson » reply Ok Gene. The silicon bronce
NELSON -
Tuesday, February 12, 2008 - 11:21am
Ok Gene. The silicon bronce on stainless-copper is clear. Now,copper to copper no chance of MIG welding 3/16" sheet w/0 preheat ?? No copper wire option to MIG it? unless I get grilled ? Thanks so much. I hope I might be able to give a valuable piece of advice too. Gee dat`s a tough race,ain`t it? Nelson. » reply  Big Project
warren -
Thursday, February 14, 2008 - 6:04pm
Nelson, Now if you have really long branches than maybe you may need an armature, but working copper sheet branches and trying to match the shape of the armature sounds like too much work. warren » reply Warren let`s say we forget
NELSON -
Saturday, February 16, 2008 - 11:28pm
Warren let`s say we forget the 3/16" Cu sheet and talk about 1/8" from now on. Don`t you use TIG welding at all on your copper work? How`s the strength and color on that Harris Ophos Cu rod? Frankly,I like the texture effect of the O/A torch welding the sheet.What about the penetration of your bracing.You seem to know about numbers on the topic. Any idea aproximately,of the pounds Cu fill rod in 10 meters weld of 1/8" sheet? Warren, I`ve done bracing, but never straight enough to calculate O/A gas consumption per meters or hours of welding.It`s very important to know a stimate,because in this case ,metal+labor+gas will be important factors to consider towards the total cost of the work. Did you ever use a "copper color silver solder" for copper? Warren thanks for your imput! Your copper tree is beautifull and well,I hope you don`t mind but for now and probably a long time I`ll remember you as the "Dragon man" » reply "copper color silver solder" for copper?
warren -
Sunday, February 17, 2008 - 1:09pm
Nelson, And no I have never used the TIG in my work, I do not own one currently. » reply Hi Richard: Excuse me it
NELSON -
Saturday, February 16, 2008 - 10:46pm
Hi Richard: Excuse me it took a while to answer your suggestions. Actually,I wanted to have more information on hand before I could even understand well the tecnical advise I was getting from all of you guys.Well,a this point the armature material and welding to sheet is taken care of. » reply Hi Richard:you mentioned
NELSON -
Tuesday, February 19, 2008 - 10:39pm
Hi Richard:you mentioned that you do quite a bit of TIG welding copper. If you were to TIG 1/8" Cu sheet with Harris O Phos copper rod,and the weld would be overlap at an average speed, how far say one lbs of rod, would take you welding (feet wise).I know it may sound dumb, but I can calculate the aproximate length of beads of welding for a proyect.If you don`t use that type rod, any other`d be okay just to have an idea. Does the rod length take that far laying a bead? Namely, if the rod is two feet long, would and average bead (one pass)get to be that long? Richard, any idea as to amount of rod and in regards to gas, any idea as to how much welding (feet of average beads) from one of those about 5 ft gas cylinders. Any help is greatly appreciated. nelson » reply |
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ArtMetal
I would use stainless for
I would use stainless for the armature and TIG braze the copper to it with silicon bronze rod, as I believe Ries Niemi once suggested. If Ries says it, you can count on it being accurate.
As for TIG welding the 3/16" copper, sure you can get a full penetration weld, but it will take some fair amount of juice to do it. Copper has a very high rate of heat abstraction and you have to overcome that quickly or you just slowly heat the general area until you have a puddle wher you wanted to have solid metal. So you weld it much the same way you do aluminum, by jumping on the pedal with both feet at the start, and then backing down to a level that will sustain a puddle but not blow out. You're going to want to practice a fair bit on scrap to get the feel for it.