Copper water tray - TIG welded

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This is my first time fabricating something out of copper - a water tray, 18" x 4" x 1.75" tall.  This is a humidifying tray for holding water on top of a wood burning stove, to humidify a room.I kind of had fun with it.  I TIG welded it from two pieces of .020" copper sheet.  I am not sure if it was "deoxidized copper" or not, but it did weld pretty nicely once I got the setup and technique figured out and dialed in on test coupons.  One destructive test I made on a test coupon involved edge welding two pieces together, unfolding them to flat by 180 degrees, then hammering/planishing the weld bead out flat.  The weld held without cracking - which is pretty good, I think. I dialed in my setup on some scrap pieces.  I experimented with 1/16" silicon bronze filler rod as well as with thin, cut off strips of the parent metal, both of which welded similarly under the TIG arc and gave similar quality results.  But I could not get as good looking of a weld bead aesthetically as I could manage on this very thin material by welding the edges of the sheets together autogenously (without filler rod), so for the final piece I went with no filler rod.I used some low speed pulsing to add some pleasing ripple texture in the weld bead as well as to reduce heat input from welding.Cutting the .020" copper stock was very easy - just used common scissors and tin snips.  I welded the long seam joining the two pieces on the edge, and then unfolded the joint 270 degrees, to orient the protruding edge weld bead on the inside of the tray, and keep the outside of the tray smooth.  (Wanted to keep the bottom of this tray flat, for good heat transfer from wood burning stove underneath.)  The unfolded weld seam has kind of a neat look to it.I found that the copper would oxidize if it were not shielded by the argon until sufficiently cooled - very similar to stainless.  I'll bet copper could be welded very nicely in a vacuum chamber, or perhaps back gassing techniques, larger cups, and gas lenses could be useful.Last edited by jakeru; 01-25-2011 at 12:12 AM.
Reply:Nice work, looks great."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Lookin good, I haven't messed with any copper yet. Require more heat then what you thought?Tim Beeker.
Reply:norite - thanks man!tnjind - yes it does.  The rule of going "hot and quick" to limit heat input I found useful for copper.  I don't have a real observed number from when I was actually welding on this piece (as I was using pulsing as well as footpedal), but I'd best guess I was using about 24 amps average or so edge welding this .020" thick stuff.  The heat can also really flare out at the end of the weld, especially approaching where the material ends where less heat conducts away, so you need the tungsten and footpedal to work well at really low currents too.  Good tungsten grind (for stable arc at low current) is important.  I was using a 1/16" tungsten.  I found my DC arc was more stable at low currents than AC arc so I went with DC.  If needbe you can just stop the weld, wait a few seconds for the heat to dissipate and cool, and finish the weld.  A copper workpiece cools off really quickly.   On this thin stuff, going without filler rod really allowed me to crank up the travel speed too.  The heat travels really quickly and if you linger too long, before you know it the entire piece will be oxidized.  (thick copper oxide is kind of a black/gray flakey stuff.)  I didn't really plan for it, but was pleasantly surprised to find that edge welding eliminated a lot of the backside oxidation I expect I would have seen otherwise.
Reply:that is awesome.
Reply:nice work.
Reply:look great
Reply:Great work, I love copper.Regards,RobGreat Basin WeldingInstagramBlue weldersRed weldersMy luscious Table DIY TIG Torch cooler