How can I make the detail of this map stand out better? I have been etching a map of the United States into 9 slate sheets (8" by 11" ~1/4" thick)

Originally my goal was to try and inlay wire into the groove that I cut with a Dremel. I found colored "beading wire" at a local hobby store in various colors, and a couple different metals. So far, I have had trouble matching the depth/width of the cut, to the gauge of wire. I also have a small set of hobby files that I can use to widen, and slightly deepen the cut, but my overall concern is that it would be extremely difficult to properly bend the wire for all the contours of some boarders. I wanted to avoid cutting the wire into small sections because I fell like it will end up leaving noticeable gaps throughout.

The only other wire I have tested was soldering wire (lead / tin- very soft) which I was actually able to gently hammer into the groove of a test piece, however it still is fairly dull and does not stand out well. I think if I were to heat it, it would improve the sheen, so that is an option I am also considering.

In both images, I have a line of soldering wire running along the west boarder of North and South Dakota as an example. From an angle, the engraving alone does stand out a bit, but I would still like to improve it.

It is possible to use a slightly larger dremel bit and widen all the cuts, but I would like to avoid this as it would ruin some of the detail already present. I am not sure how it might turn out if I used a larger bit to widen the more open lines, and then left the 'crowded' areas as-is.

The end result will have the 9 sheets mounted to a piece of ferrous metal, to allow placing magnets across it. I glued a thin felt sheet to one side of a neodymium magnet, and placed a weaker, souvenir magnet to the other side.

Edit I failed to mention that for fear of hammering any harder wire into the slate, I planned on using 'jewelry and metal glue' which claims to bond metal, stone, ceramic, ... among other things.





Final update - I have tested using gold leafing with a brush-on metal leaf sealer. I had the option of leafing flakes, or sheets- I went with flakes because I thought they might be better for the less straight boarders, but I will probably go back for the sheets as it will probably be easier to just cut them down into manageable strips. It is extremely visible, even from across the room. I am going to let the sealer dry for a bit before cleaning up the areas around the lines, and I may try putting some masking tape down before I do this on the final map.
I would call inlaying metal wires into slate a high-risk project in general.


You already managed to carve the groves - congratulations for that!
Slate has the tendency to chip or break when hammered
Colored wire for jewelry often has a very thin coating of color over a soft metal core (often aluminum). Hammering that into the groves could damage or remove the color coat.


Add to that the fact that the contrast between slate and soldering wire is not very high - both appear silver or grey, depending on the lighting.

My first advice for this project is to use a contrasting color for the groves. Anything but black, white, silver or grey will stand out better.

Because of the high risk of breaking a sheet, I would not hammer anything into the grooves. Filling the grooves with a liquid promises more success. 

One idea that you can test for a low price is good old Window Color. Buy a bottle of Window Color contour paint - these have a thicker consistency and a higher pigment content. Test the paint on the back of a sheet and see if you can peel it off in case something goes wrong. If you're satisfied with the test, squirt the paint into the grooves and let it dry. You can thin the paint by adding a few drops of water to the bottle.

A better shine might be possible by using metallic nail polish. I suggest transfering the nail polish into a squirt bottle with a thin nozzle that fits into the grooves. Both (bottle and extra thin nozzle) should be available online or in good crafting stores.

Metallic permanent markers might work as well, if the tip is thin enough to fit into a groove. Both nail polish and permanent marker can be removed with nail polish remover, but the grooves probably make it harder to get all of the paint out.

Another alternative that promises an even and shiny result is enamel color. These are often used for model painting and have a high pigment content, like this example by Revell. The only disadvantage is that I don't know how you could remove it in case something goes wrong, but I'm sure the manufacturer will provide more information. Use this paint with a squirt bottle as well.

In any case, my experience with slate as a crafting material is this:


Before applying any paint, wipe the slate off with nail polish remover to remove any oily residue
Slate needs extremely long to dry. It took almost a whole day in my case and in the meantime the slate looked blotchy. It's only dry when the whole sheet is a uniform light grey.
Test any paint or nail polish on the back side. The structure of slate can make some colors run and bleed into adjacent areas.