Thanks for these great variation of armature approaches! Although this particular tutorial was regarding polymer clay, just thought I'd add a note about using aluminium foil with oil-based clay. Personally I've found if you're planning to reclaim and reuse the clay down the line, oil-based clay doesn't always peel away from the foil without it ripping. This can leave very small aluminium shrapnel in the clay. Which isn't ideal if (like me) you reheat oil-based clay in the microwave. So in that scenario, I tend to add an external layer of a different material to the foil (like sellotape) before applying the clay. Just so it parts from the clay easier.