Auto body repair & detailing: Front bumper?, grit sandpaper, pontaic firebird

Question
I have just removed the paint off the front bumper of a 1988 pontaic firebird and i believe it is fiberglass but it seems like it could be plastic and i tried painting it today and the spray paint would not seem to stay on evenly it would make blotches like it didnt want to stick could you please help me? Do you think it isnt sanded properly or is there a special kind of paint to use because i just used some regular white spray paint that i had lying around? And do you know how to remove the plastic siding on the doors thats for like when shoping karts or doors in a parking lots hit your car? Please E-Mail me back! THANX

Answer
You need to remove all paint from front bumper using 220 grit sandpaper by hand. Then you need to wash off with soap and water. Let dry.  tape off area that you dont want overspray too get on. Then apply three or four coats of primer.  You can get this at your local parts store. let dry 24 hrs. Wet sand out primer with 400 grit wet or dry sandpaper.  Do not sand through exposing bumper if you do, reapply primer when dry. sand again do not sand through primer. Sand untill smooth. paint with flexable bumper paint. DO NOT TRY TO COVER IT IN ONE COAT. three or four coats should cover.  As far as the moulding goes. Use a putty knife and start at the rear pushing forward between the car and moulding. if it is double sided taped, once you start it, pull the moulding off at a 90 degree angle slowly. if it is held on with clips you are out of luck because the panels have many little tabs welded on to to hold moulding securly.   Tabs have to be ground off primed and painted. big job only a pro should do.

                           hope this helps  Brian