What are these being made out of?

wire and Car bondo. and some heels that I don't use any more. :3

I'm sorry to hear that. I've made a pair similar to these in year's past and they looked amazing.
http://www.furaffinity.net/view/5797189/
http://www.furaffinity.net/view/5797285/
Sadly, they were destroyed within a few weeks of general use. The left hoof shattered into 3 large pieces. The right one lasted a few more days after before suffering the same fate. I was very upset as the time and effort put into these is very high, as we both know.
So, I tell this to you as a fair warning, and I do hope yours continue to last much longer and proves me wrong.

aww sorry to hear that. well that not all I'm putting on them. I do a lot of fiber glassing, sealing and other stuff to put onto them. so my friend is going to help me with that. I know the feeling sadly for, I made hooves before. live and learn as I say. but that really a shame. :/

Yup, the newer pair I made have lasted quite a while now. Need to do a quick retouch on the bottoms again but so far not a single crack. Wonderflex is amazing stuff ^.^