this may help. I have found that the primer sold by games work shop works, I spoke to phoenix about there paint as I had bought some and had it on stock about two years and wonderd if it had a shelf life, he said id did and to test by test spraying a scap and leave to fully dry then do as Alan has done and use your nail and if it comes of it Pants ! I dont think he needed to tell me the last bit. I just binned it all and got some games workshop stuff for there Citerdel models
Phoenix Precision Paints