For my next screaming skull catapult, I am modifying a Finecast dwarf grudge thrower. Remember the GW basing kit
? Well, I took one of the resin bases of skulls and cut it up. It tends to snap sharply when you cut it, so then I'm going back in and adding more skulls around the sharp edges. I'm going to glue these skulls to be the ammo of the catapult. Since they're supposed to be flaming skulls, I'm thinking I'd like to make some sort of "hot coals" effect. I want the skulls to be normal white at the very top, then black/grey where they are getting charred from flames, kind of like hot coals. I'd like to create some kind of glowing red coal effect in the recesses where the skulls meet. Something like this:
I have no idea how to go about achieving this. Any advice would be helpful!