Body filler is a thick, two-part polyester resin, commonly called Bondo. Caution: Bondo is flammable — keep away from heat, sparks, open flames, and hot surfaces. Wear protective gloves and eye/face protection.Click to see full answer. Also know, will Bondo hold up to heat?Bondo doesn’t so much melt as burn. It is made of polyester resin and a powdered filler. It is about as durable as paint under heat. If you want more detail you could look up polyester resin.Secondly, are body fillers heat resistant? Coaters need a metal repair filler that can be used under powder coating, is heat resistant and able to take the charge of the powder coating process. When using a one-part body filler like Lab-metal or Hi Temp Lab-metal, you can simply allow the repair to air dry, then sand smooth and powder coat. Similarly, you may ask, what temp can Bondo withstand? Not sure about other brands but Evercoat Rage filler is good to 260 F surface temp. Thats the only brand of bondo I use. As for it being good for that area it should hold up just fine.Is Bondo bad for your car? Bondo 101 – Working With Plastic Body Filler There is not a more maligned automotive product than “bondo”. Every high-end custom car or restoration has body filler on it. Using it on your daily driver or project is not a bad thing, as long as you use it the right way.