I recently wanted to do a bunch of similar sign engravings (same font and size for each, but different text) and thought the way that most sense would be to create the first sketch, then make a copy of it and edit the text for signs 2 through n, then finally go back and explode the text as required in each. I was surprised to discover that they is in fact no way to copy a sketch.
I don't think that making the first sign sketch, exploding the text, then going into the CAM environment, post processing the gcode, then returning back to the modeling environment would work because I'd have to be able to undo the explode text operation so I could edit it, and as far as I know once you exit a sketch you can't go back an undo individual operations in that sketch.
I ended up making a new sketch for each sign from scratch.