Abstract: A cover for covering an air bag in a motor vehicle has a thin elastic plastic skin, a rigid substrate and an intermediate layer of soft plastic foam. The skin has a tear seam and the substrate includes a door that is impacted by the inflating air bag and presses outward against the foam layer and the skin to tear the foam layer and the tear seam and then swing outward with a torn section of the foam layer and skin to form an opening in the cover for deployment of the air bag into the passenger space in the vehicle. The tear seam in the skin has a score line formed by partial perforations defined by tapered holes that are evenly spaced and formed at a controlled depth on the underside of the skin by a lasing method.