Automotive Plastics: wheel well plastic needs repair, perforated metal sheet, hot melt glue

Question
While doing some custom work on my car, my friend cut away part of the black plastic surrounding the front wheel. He actually cut away too much of the plastic. I would like to patch part of it. Do you have any suggestions how to glue a piece back on?? I have been reading about how it is difficult to glue polypropylene.  What about welding? What about a fiber glass patch??

Answer
Hi Gail, Thanks for your question. You are right, the only way to fix a PP mud guard is by welding. If the cut is a big one I suggest to make an initial approach of the two severed parts is by joining them with a few plastic cable ties(the smallest type).Then with the help of a 40 watts soldering iron insert some pieces of perforated metal sheet cut from the grille of a discarded loudspeaker, shaped square 1/2" or less. Use the thinnest mesh so they can be inserted in the middle of the plastic. Normally mud guards are made in the order of 1 to 2 millimeters thick. use as many metal pieces as you can in the invisible side of the part. This must be performed in a perfectly clean surface. Then finish by adding some hot melt glue with a gun for further reinforcement along the cracks. If you understand and follow these directions you will have the strongest union. Finally, cut the ties off or let them stay if the were installed from the invisible side. For improved presentation in the visible side you may use any black sealant to fill the crack. Feel free to ask for more info. if I was not clear enough with this explanation. Regards