This part of the process definitely goes more slowly. I press polymer clay into the cardboard edges so that on baking the bases become quite rigid. Then I wrap each in more clay to be certain I have most of the gaps filled. Following that, I use a 1″ square template I cut from an old cassette tape case pressed to the top of each tile as the straightedge for cutting. A new razor blade made short work of the excess. Once all these are done, they go into the oven. After that, it’ll be time to apply the textures.