I currently have multiple sheets of slate measuring 8"x12" at 1/4" thickness, and various gauges of colored wire (picked up the wire from the Beading section of a hobby store).
I have been scaling a map of the U.S. onto freezer paper, that once complete will be a 26"x40" map outlining the individual states.
I would like to engrave the map into the slate, and then fill the channel with metal to make it more visible. In some tests, the only metal that was softer than the slate was solder wire (tin / lead, not sure of the %s) which allowed for hammering it into the channel for a good fit. With any metals I tested, they were too hard and would essentially hammer through the slate, and so I have decided to use a jewelry metal glue to inlay the wire securely. This gives me a little leniency on the depth, and width of the engraving, but I am looking to use either 18 / 20 gauge wire.
I have tested a few different Dremel bits made for engraving, but I am currently using the Dremel accessory 108 1/32" Engraving bit, with the depth adjustment attachment. I have okay results, though find it difficult to keep an accurate line. Additionally, I had a lot of issues placing a sketch overtop the slate and trying to engrave through following the pattern on the paper. I held the Dremel perpendicular to the slate, and attempted to use it like a router, but it still had a tendency to walk a bit. While browsing the Dremel site, I think it looks like the '125 1/4" Carving Bit' may better suit my needs, as it would have better cutting power in lateral movements.
Would it be better to keep trying to leave the paper on top of the slate, or to cut out the individual states and trace them with the Dremel? While I would prefer to try and keep the depth consistent, would it be better to handle the Dremel freehand, more like a pen, than perpendicular to the slate?