Nylon is a plastic with a very high melting point and is used in places where high temperatures are present, like radiator tanks and intake manifolds. Nylon has a very distinct smell when melted. Because of the high melting point of nylon, it is often necessary to preheat the area you are going to weld with a heat gun. This will make welding much quicker. Because of the pressure and temperatures on nylon radiator tanks, it is very important that the rod fuse with the base material. Anything less than a complete fusion repair will result in a money-losing comeback job. This is a 30 ft. (9.1 m) package. Each rod is 1 ft. (30 cm) long and there are 30 rods in a pack. Each rod is 1/8th inch (3 mm) in diameter.