I’ve been asked about how I sculpt chapter badges on shoulder pads more times than I care to remember so here’s a quick tutorial into how I do it. Other more talented sculptors probably have better approaches and results but this is how I tackle them. In this example I’ll be making an Alpha Legion Icon from before the heresy (the A with a chain across it).
I’d recommend attaching the pad to something easy to hold, otherwise you may end up with hand-cramp or very likely you’ll damage the sculpting with your fingertips by mistake. Some poster tac (blue tac) is usually sufficient though I often use a tiny amount of glue that can be removed later on.
Start with a small ball of GS. In this example I used more yellow than blue in my mix, but thinking about it, using more blue would help keep sharp detail better (and make it less sticky). Using a clay shaper or other soft tool spread the GS evenly over your chosen pad. The only thing you are trying to do at this point is make sure the area you want the icon to be is covered and that the thickness of the GS is consistent and follows the curve of the pad. Gently smooth off.
Now that the depth of the GS is even throughout you will not have to address it again, and that means one of your three dimensions is sorted. Next you are going to trim away all the GS you don’t need and slowly revealed the icon.
Begin by trimming the edges, making sure the shape stays symmetrical and isn’t lopsided at any point. All this should be carefully done with a sharp clean scalpel. After cutting this away you may want to neaten it up as you go. Notice how you are just cutting away at the edges and that the thickness of the GS stays the same.
Continue to trim away at the GS until the outline of the shape you are after appears. Take your time and don’t rush as mistakes are hard to rectify with this approach (you don’t want to have to add GS, only take away).
Once the outline is established and excess GS around the icon is cleaned up you can begin with the inner details. In this case this was all done with a scalpel blade but other metal sculpting tools (quality ones at least) would probably serve better. Using the sharp edge of the scalpel press carefully into the GS, scoring the lines.
Once the icon is complete and fully cured you can of course make simple one piece molds (Blu-Stuff anyone?) and cast as many as you like for you armies.