emax72085:
I also have been exploring blackening the slide of my SW40VE.
I tried a product from Caswell Plating called "Stainless Steel Blackener 370" (gel). It does not work. Wasted $30.
I am looking into a Moly resin product from John Norrell Arms. I have used it on an aluminum receiver. One needs to sandblast the piece with aluminum oxide (60-90 grit), paint with a pen airbrush, and bake. If one takes good care of the preparation, one gets very good results. The website has thorough instructions. Do a search.
Regards,
argon