I am rebuilding a 71 xy falcon and as i have been repairing sections i have been painting in acrylic prime. I have finaly made my mind up on a colour. Satin black in two pack. Two pack as i can get a two pack that does not shin up when rubbed or buffted. So can the two pack prime go over the acrylic prime. Also is it true that i should remove all old paint back to metal when using two pack. Thanks for any help. Cheers calvin.