So, I'm working on my Ryan PT-16 for the Funbuild 4, and I've run into a dilemma. My motor is 23mm in diameter with a short shaft. I'm not crazy about the idea of drilling a large hole in the balsa cowl I've built. I can just see it getting shredded before it's all over. Well, I've always wanted to learn how to vacuum form. So today I built a box and a frame, fired up the ol' toaster oven to 350 and tried my first pull. Not a complete success... made a second and third attempt... getting better... A fourth pull actually turned out real well. Except for the part where I try to retrieve the plug. Got stuck in there. Couldn't get it to pop free. I ended up tearing the piece that I made (see pictures below).

Question is should I have coated the plug with something? A release agent? Livin' and learnin'