OK guys, question for all you panel beaters. from my limited google research, i've come across mixed opinions about painting these two types of paint over one another. here is my story: 1) sanded back the interior plastics and got rid of the shine of the original colour. 2) sprayed it with metallic black (acrylic) 3) wasnt happy with the finish and sparkly bits so i took it back with 320 grit paper and tried to take back all the acrylic off 4) panel shop painted 2pac on (no primer) over the part 5) there is a wriggly line on the bloody corner of the part! :( apparently to the panel beater, the glue type substance came up when he was using the wax and grease remover when he cleaned the interior bits before he painted it. the ONLY interior part affected was the gear shifter housing. the other panels i made sure all the acrylic was off before i gave the parts to him. just the corners of the gear shifter housing was hard to get the paint off so i gave up and gave it to him instead. now would it be ok if i just sanded it back lightly and buffed and polished it up? or do i need to sand it back AGAIN :( and then have him redo the part again? also as a general rule: is it OK to paint 2k on top of 1k or do you have to take everything back to bare plastic and prime it etc before painting it? we thought the interior parts aren't going to be exposed to the outside environment so its ok to not use 2k primer before painting it. He said if he used primer, i'd have to sand it back = more work = not necessary. so we didnt end up doing it. thanks in advance for you input guys. cheers