For repairing bumpers, trims and small structural plastic components I work to predictable mechanical principles: prepare the joint, apply controlled heat or a purpose-made adhesive to re-form and bond, then reinforce where loads concentrate. In practice that means using controlled plastic welding or specialist adhesives with backing mesh, studs or plates for strength, followed by finishing and priming. Selection advice: identify the substrate, choose a compatible method, prioritise equipment with temperature control and always test on scrap before final repair.