Hi! I am super beginner in making pottery. I'd like to make a pot thin but hard like metal. I've found a pot in a garbage looks like this https://cookniche.com/Photo.aspx?name=MitchiburgCeramics&IDservice=11440 it seems like it has irons on the surface. Would these irons make the pot harder? or is this only for decorating the surface? could you let me know any other ways to make a pot harder? thanks!