Sorry, Dave,
Your sequence is : "bare metal, then epoxy, then filler, then primer(s), then sealer, then paint"
With the PPG product-lines we used, we followed this sequence:
" . . . fillers on top of epoxy primer that has been applied to shiney cleaned metal . . ."
derusted, repaired-as-needed shiney "washed" "bright" metal
then epoxy primer
then sealer/surfacer
then urethane top coat (two-part urethane, single-stage application)
