The ShapeLock instructions describe it as "modeling clay on steroids" and I have to admit that I agree with them. This stuff rocks! Boil some kernels in some water and mold away.
It took me 45 minutes to mold these four tooth pulleys per the RepRap instructions.
I didn't expect the results to be so good! My only concern is that I made these pulleys too small for the Z axis. We will have to see.