Recently I became acquainted with using an audio 'test probe' for circuit troubleshooting, through this site: BillM Audio - http://billmaudio.com/wp/?page_id=1254

New to me is soldering a wire/lead to a nail. My first few attempts at doing this have been less-than-stellar (using 40 w iron with rosin core solder).
My nail is approx 1.5 inches and the composition is uncertain (it is silver-ish colored and from the hardware supply).

I was wondering if I may need to use a copper nail or perhaps a shorter/smaller nail (to prevent heat sinking)? Maybe I would need to use a soldering gun or torch, or another type of solder?

Has anyone else here had experience with this type of soldering or making of a probe like this?

Thanks for any helpful thoughts or suggestions.

A galvanized nail? Really? Have any old test leads? A cheap $2.99 harbor freight dmm comes with 2 leads. Pointy on one end, banana plug on other.
Usually they're about 24in long. Sure a copper nail would work. Clean surface VERY well, then tin just where U'r going to solder. Uses good quality wire,
Strip insulation, twist strands together (yes, only use stranded wire), then tin the wire. Now solder the wire end to the tined part of the nail. I Still think cheap test leads are your answer. Ahywho Get that PAiA Phlying!!