Installing a series of 3/16 thick carbon steel stair runners. On gates and railings, I usually weld up and then wipe them clean with a paint thinner to remove mill scale and oil, then cold spray galvanizing paint on the metal. Then finish with two oats of black oil-based paint as a cover.

For these steps though, many areas are coated already with the blue layout fluid. Is the commercial cold galvanizing paints effective over the layout fluid, or a waste of effort since there is a few micron's between the galvanizing primer and the metal? Or just accept as-is, and apply the top coats as usual? No salt spray, but outdoor exposure.

Commercially, I've seen many items coated with the Dykem Blue in the laydown yards for CT and turbine internals that will go back into the turbines, but need a short-term coating against incidental rusting. Obviously not a permanent coating, but will it foul up the regular paints if left in place?