The art of inlaying wood with copper dates back to the Qing Dynasty in China (1644-1911), when elaborate designs were inlayed in wood with copper plate and often enamel. The art of copper inlay is also used today when a visual impact is sought in woodworking. The process is a little complicated, but you can try it yourself when making furniture or signs.
Plot the design for your inlay. This is important, because you want to know exactly what your design is before transferring it to your wood. Draw it on graph paper, and make use of the squares to do your drawing to scale.
Transfer your design onto the wood with a pencil. Cut out the design with a router.
Mix 1 part resin and 2 tablespoons of copper powder in a container. Make sure you do this thoroughly so that the resulting colour is even.
Fill the routed designs you made in Step 2 with the mixture, poking it with a toothpick to make sure you fill it in completely. Try to work quickly, as the resin can set up in a short amount of time. Make sure also that you fill the routed design so it's a little crowned, or slightly rounded above the surface, without spreading onto the rest of the wood. When you finish the batch of the resin and copper powder mixture, repeat Step 3 until the entire of your inlaid design is complete.
Allow the copper inlay to dry completely. When it is dry, sand it with 80-mesh sandpaper and an orbital sander.
The fumes from the resin and copper powder can be harmful. Make sure you work in a well-ventilated workspace.