This can be from any source, but spent bullet cases are also suitable, so if you know someone who goes shooting you may get some from them.
The earliest reference I can find to cell punching is in L.E. Snelgrove's book "Queen Rearing", where he writes of an article in "Journal d'Agriculture" of Quebec published in March 1918, which details a method by E Barbeau. Mr E Barbeau, of St Eustache, Quebec had an article published in the July 1919 edition of the American Bee Journal (ABJ)
I think you are referring to heating the cutter prior to punching each cell. A compression sleeve is quite fat so it does not cut cold so well. The cutter from a cell casing is very thin making heating unnecessary.Made one a few years back by brazing the head end of a finish nail onto the fitting and pressing the pointed end into a pre drilled hole in a piece of dowel rod.
Don't solder it, melting temp of solder is too low if you get a little liberal with the heat.