Originally Posted by rlackey
So if the pitted areas that used to be rusted badly are clean now but black, I can primer directly over it?
I will go ahead and sand through all that nasty yellow coating then as well.
Re-apply your acid and wire brush the area as many times as it takes to get all the "black" removed.
In heavy pitted areas this may take as many as 20 iterations to get rid of all the rust. If any holes in the metal show up, weld them or fill with lead. Then sand with 80 grit and prime with epoxy primer.