I believe he asked how to do a RELIEF inlay such as often seen on a fowling piece. To make this, you have a couple choices. Cut it out and file / chisel it to the shape you want. Make a master out of a more favorable material to carve and shape and then make a casting off of this master. It seems the English used a very fine sand that gave excellent detail. Most sand casting done today is much coarser. Another option would be to use investment casting. You have a few options here, but it would require a lengthy explanation. I'll explain futher if you're interested. A final option would be to use the Delft clay method. Seems I recall a good explanation or tutorial of this process from Dave Person. Hope this helps.