It's really funny that you posted this, because I came up with the very same solution last Friday night. Those concave sections are tough. I'm not quite done (My seat is 6 inches deep), and I'm looking for a tool that I once saw - a sureform (rasp) with a flexible steel face wrapping around an outside radiused blade holder. Any of you guys seen one of these? I may just make one by tacking a dragon skin to a piece of wood.

> I just finished carving a foam seat out of minicell foam for my Artic
> Tern. Using a rotary wire brush fitting, powered by my variable speed
> drill, I was able to carve most of the seat in about 10 minutes. This
> seems like an ideal tool for shaping a 3" deep, 12" X 17"
> block of minicell foam.

> I tried heavy sandpaper and a surform, but the wire brush worked much
> better, allowing me to sculpt the foam in a short period of time.

> The seat seems pretty comfortable, but I'll only know after a test paddle
> tomorrow how it feels during an extended paddle.

> Paul Williams, Port Orchard, WA