There's lots of ways to do this, but this is how I do it. Maybe it will help.
first I sand my blades to 1500-2000 grit (mirror finish) then I tape the blade to protect the finish, then fit and soder the guard on.I sand the face of the guard to at least 600 grit before I soder. then I very carefully put finger nail polish on the guard to protect it from the acid and hang the blade in a jar of 5 to 1 ferric cloride with just the blade covered and part of the guard. leave 10 minutes take out and sand lightly with 2000 grit to remove oxidation and then place back in the acid, I do this every 10 minutes until I get the depth I want. after etching I spray the blade down with ammonia, scrub with an old wore out tooth brush and rinse with clean water, dry the blade off and then lightly oil. Continue on with the handle.
Good luck
Bill