as a rule i always sand befor putting on any coating even if u have already sanded it monthes ago if it is the last coat u are going to put on before paint 400 will work great mp2k builds nicly so u could even sand it with something rougher no more than 180 just to nockit down fast than finish withn400 it was late when i typed this so let me no if u have n e ? sometimes things i do after midnight only make since to me
