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In Laser Transmission Welding (LTW), a laser beam passes through a transparent part and is dissipated as heat in an absorbent material through the use of laser-absorbing pigments such as carbon black (CB). This energy is then conducted further into both parts. Melting and subsequent solidification occur at the interface causing a weld to form between the two parts. Gluing or welding structures to the back of automotive Class-A panels often results in the appearance of undesirable surface deformations on the Class-A side. Through control of the laser welding and material parameters, it may be possible to use contour LTW as a means of joining structures to the back of absorbent Class-A panels without creating these unwanted surface defects. A series of lap welds was made using a range of CB levels and laser powers. A profilometer was used to measure the size and shape of the defects generated on the surface of the black part. Two types of defects were observed: ribs and sink marks.