Comment by Galactic Navy Officer on Fratos

Comment on ReplyFratos
Basic clay heated on an open fire can make low-quality pottery. It won't last long and will wear out quickly, but it's possible.

The biggest issue is making sure there are no air bubbles in the clay when it's heading. If there are, well, it's air heated in an enclosed space. Hopefully MC was out of range if that happened.
The Galactic Navy Officer Becomes an Adventurer
by Takuma Tomomasa , A_Itoh
Available on mangabuddy for reading, and for sale at  https://www.amazon.com/dp/B0BT6V7CMM