I also etch my name on after final sanding. My etch machine is a personalizer. I put it on etch (DC), and hold it on for 90 seconds, etching it very, very deeply. Then without moving anything (stencil or etching pad), I switch the control to mark (AC), and hold it one for about 20 seconds. The DC setting puts a very deep etch in, and the AC setting turns the etch very dark black. I have tried filling in my etch with fingernail polish before etching the damascus. I just clean it up good and etch as normal in my Ferric Chloride and I get a good mark. Attached is a photo of the results I get.