well actually you were totally correct, it doesnt oxidize, it sulphurizes ;) but poster above, sorry but you are not correct; copper oxide is BAD for audio, as its not a good conductor and causes serious degradation of the signal and eventually physical properties of the metal, where silver sulphide is still a better conductor than pure fresh copper.
the OP's proposed cable would be a bit stiff but not over the top. if you must use cotton (silk is actually more flexible) its quite difficult to thread through multifilament nylon techflex, the normal microphonic as hell techflex goes on easy, but not the soft black nylon. unless its quite a bit bigger than the braid. you could add a shield or tefloin tape over the braid to make it easier to thread, but I definitely recommend using 26AWG. 24 is what you have actually 0.5mm is about 24.5AWG
Edited by qusp - 9/6/10 at 6:12am