sounds like your not using a scuffing agent or adhesion promtor...most lips are made out of abs plastic which require a very fine scuff or sanding...if your sanding use 600 wet/dry paper...if your scuffing.. use a gray 3m scotch pad with a scuffing agent after all said and done wash with soap and water and dry throughly. apply 1-2 coats of adhesion promoter and let that flash before spraying any kind of paint
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