Does anyone who has watched American Hot Rod on tv know what kind or filler they use to spread over the entire body of a car? I `m looking at filling glass mat that has been laid over plywood to get a good smooth surface , I don`t think the stuff they`re using is bondo, you wouldn`t be able to spread that much before it sets. Any one got any ideas what they`re using? RCM Contact your local autobody supply shop and I believe there is a product that you can add to bondo that makes it spread easier and lets it stay that way longer. There is a catalized body puddy that Evercoat makes but anything that gets catalized only has a certain amount of time that you can work with it. The additive I think has the word HONEY in it. Hope this helps.