You'll also need the Weaver and Stone Tools feats. The Armorer's Bench can be crafted for 240 Stone, 160 Wood, and 20 Twine. It's worthy to note that thick hide is often found on larger beasts and predators, such as elephants, frost giants, and rhinos.
Below you will find a complete list of all creatures with thick hide in Conan Exiles.
The best way to obtain thick leather is to hunt animals with thick hide.