Well,I guess that I should "Fess up". I purchased several hudred oz of the stuff and ran into a couple of issues .The first thing that happened was that I punched out a ranger style buckle out and was soldering it together and it slipped off the screen and hit the floor.SPLAT

and shattered..

When I did get one put togather I was trying to use the reccomended solders and they didn't flow very good

.
I don't know about engraving on cast buckles but the arg. sheet materials engrave very nicely.I was able to oxidize it with liver of sulfur.
I was thinking that it was sort of a magic bullet and am a little bit dissapointed with the results. I can't say that I would buy too much more of it after this discussion.