Great Sounding DIY Speaker Cables
See the bottom of this link:
http://www.audiosold.com
one of the dumbest ideas ever
Bare wires??? You are only minutes away from a kick, child or cat having the cables touch and short and say goodbye to that pretty little tube amp.
Not to mention surface area has increased true...but unprotected and non insulated will ensure a lot of surface area oxidation in no time.
You are better off taking two insulated ribbon cables one per polarity at least they are insulated.