copper wire

[hollyuk]

Hi,

I am an art student currently doing my sculpture module and I need to know what would turn copper wire black (apart from a flame...tried that!).   Is there something I could rub on the wire to change it?

Any tips would help, thanks!

[Clanad]

Check what this artist did with copper sheeting... should work with youe wire... Luck!

http://www.scitoys.com/scitoys/scitoys/echem/echem2.html

[kempie]

To give copper a black patina you could convert its surface to copper sulphide. This is achievable by dipping the copper wire in a potassium sulphate solution.

[hollyuk]

Thanks Clanad, I tried heating the wire but it weakened it and it then didn't support my sculpyure.

Kempie, could I use Potassium Citrate instead?   I know I could buy Potassium Citrate at a chemists not sure where I'd get Patassium sulphate!

[ursula62]

spray paint?

[gen2]

Sorry to disagree with kempie, but if my memory of chemistry is accurate, then it is potassium sulphide that you want (not sulphate).

[Hamish]

I wouldn't mess about with potassium sulfide too much. very smelly. The black colour is copper oxide- try oxidizing with bleach - or hydrogen peroxide. If your wire is laquerd this may not work and you will have to remove the laquer first - by sanding or perhaps cellulose thinners. All these materials are avalibe on the highstreet. (hydrogen peroxide will probably be as a 5% solution in water - this should be OK.)

[kempie]

gen2 - it is the presence of sulphur in the reagent that is the relevant part of the equation and so I based the criteria of choosing the sulphate over the sulphide because potassium sulphate is less likely to kill you!

[THECORBYLOON]

I posted a reply to this earlier but it seems to have been dropped down the side of ABE's settee......

[Hamish]

Hi Kempie, Pot sulfate is unliekly to do anything. The reaction would require the formation of potassium metal and copper sulfate - very unfavourable. the reduction of SO4(2-) to S(2-) would also require a ver powerful reducing agent - which copper is not.