This is _very_ cool (or should that be hot?)!

I did a little Googling and found references to the use of a ball of platinum black (which is very finely powdered platinum) or a platinum sponge, both of which would have a _much_ greater surface area than even extremely fine wire. So I suspect you are on the right track in trying thinner wire but have no idea how fine you may need to go to do the trick.

-- Sam