A copper arc welder will produce a lot of copper oxide.

The exploding wire (and tape) method produces liquid copper flying at
speeds in excess of the speed of sound. When this hits a clean
semiporous surface like alumina or ceramics it goes in several microns and
is impossible to remove other then chemically. However the layer will be
very uneven. If you do this in a vacuum like Vasile suggested you can have
better results (evaporation and cathode arc plating are slow). And
building a 1x10^-5 atm vaccum chamber is NOT easy for amateurs as he said.

Peter

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