Note: The butterfly was a joint effort between Jan, owner of "The Artful Parent" blog, and her daughter.Here's what Jan has to say about making Stained Glass Melts:
First my daughter drew a picture on paper with a black pen. Then I placed the drawing on a cookie sheet in a warm oven (250•F). The book says to use a warming tray, but we don't have one, and we had used the cookie sheet method with success before. She carefully colored in her drawing with crayons while the paper and cookie sheet were hot. The crayon melts beautifully! After filling in the drawing with melted crayon, my daughter did a black watercolor wash over the drawing to make the stained glass pop out even more. We used lightweight paper rather than watercolor paper, since we weren't planning on using watercolors. I think the stained glass effect is more effective with lightweight paper (copier paper).