The paste solder you refer to using rosin flux is of no use unless the area is tinned first, since the rosin won't allow adherence to steel. If you had adherence in the first place, there would be no problem.
The talc, I've thought of, but am concerned should the talc somehow get below the solder line. If you don't get it close enough to have that worry, clean up is no better or worse, because the solder won't stick to any area that hasn't been fluxed.
The non-acidic fluxes may work well, my concern is not so much the blue, as future oxidation and pitting. These may work quite well, just stating my thoughts on that.
As far as cost goes, Galazan gets $1100 or so, I truly forget who had the $650 price listed, may have been Orlen. Brownell's catalogue lists the price at hourly rate + blueing. I've done a little of this, learned from a man who's done it for quite some time, and has seen it done even more. From what I've seen, done, and heard, it's never a simple thing. I'm not going to stand here and say that what you quote, or whom you quote, is incorrect. I will say that I'd like to see and test the end result. I'm not sure we're talking the same product, or at least not performed for the same reasons. I'll leave the price issue at that.
Jim
