The senior art club learners found the same thing! They were given a small section of tinfoil and asked to create an animal. My estimate for how much tinfoil would be needed proved to be very insufficient but this was not a real problem. The work that was produced was beautiful! (As you can see)
Tinfoil is a very interesting medium to sculpt out of. It can be very pliable though when compressed becomes very hard. Another thing one has to look out for is the way that sheets of tinfoil can separate if not crumpled up together sufficiently. We painted our sculptures with glue once we had finished the actual work of sculpting.