A belt splicer for butt-welding conveyor belts and methods for its operation. The belt splicer has clamp jaws that close to contact the butt edges of two belt sections against opposite ends of a heating wand and to hold the two melted butt edges together as they weld to each other. A toggle linkage assembly locks the clamped jaws closed and stores energy in a spring mechanism. The toggle linkage assembly allows the rapid release of the spring energy to accelerate the clamp jaws open to pull the melted butt ends rapidly away from the sides of the wand to avoid sticking. In another version, an air cylinder is used instead of the toggle linkage assembly and spring mechanism to close and rapidly open the splicer.