I put thin fire between color glass and capped with clear. I put chads under the clear to vent. As you can see in the yellow one the chads left their mark.
In the top 3 I cut shapes, triangles, square and an arrow. They didn't hold their shape. In the bottom 2 I used glassline paint on the thin fire. It didn't hold the shape that well either but where the paint was it didn't crinkle up too much. They were all fused at full fuse. In the blue one the thin fire popped through the clear cap.