Abstract: A method for repairing cracked and broken plastic articles such as lenses for automobile signal lights and the like comprises the steps of placing a form against a first surface of the plastic article such that the form covers the broken area, preparing an adhesive sealing compound which cures by exothermic reaction, applying the compound to the damaged areas of the lens from an opposite surface of the lens, heat generated by the exothermic reaction causing decreased viscosity of the compound and widening of cracks in the lens, the compound flowing into the widened cracks before curing, and, removing the form after the compound has cured, whereby repaired portions of the lens diffuse light in a manner substantially indistinguishable from undamaged portions, and repaired portions are of comparable structural strength to the balance of the lens.