I have gone through and read all the post i can find about fiberglass. I made some door panels and two accent pieces, one is a big half oval and the other is a long stripe with a raised chevy bowtie. So far i am very happy with the results except, on the actual panel it keeps curling up. What is my problem. How much fiberglass is enough? I have seen that many people say put several layers. I have 4 layers is this enough? When I layed it on the shop floor to trim it i walked on it and had no problems. But I am worried about putting the bondo on to smooth it out and then it curling back up on me. I have tried setting it in the sun and it worked but once it cooled down in the afternoon it was curled worse than before. So I set weights on it with no results. Then I tried the heaat gun. Worked great then it curled back up. So I tried using a heat gun with weights and still no results. What am I missing?