Yeah, I finally got to paint the hull in the final colors.
First I gave the whole model an overall coat of Rustoleum flat red primer. I let that dry overnight. Next I masked off the water line and deck area, leaving the area that would be blue uncovered. Then I painted that area with red primer one more time. Why? This helps seal any gaps in the masking tape. Any paint the seeps under the tape will not be visible. I learned this trick many years ago while watching Mike Lech's modeling show on PBS.
After a half hour of drying, I painted the blue parts of the hull with Tamiya Flat Blue thinned 50-50 with alcohol. This is probably the easiest paint to airbrush, as it flows readily and dries quickly. I used my Grex airbrush with a 0.7mm tip and 20 psi. After spraying about three quarters of the bottle of blue in multiple coats (yes, it is a big model), I set it down to let the paint set. During this time I cleaned the airbrush. With the paint dry, I inspected the finish and it looked good. So I removed the masking tape.
I had some blue overspray in the freeing ports, but I expected that. The next step was to mix up a batch of Vallejo Cavalry Brown thinned with Vallejo thinner. I carefully sprayed from the top down to touch up the overspray and to give the hull deck and hatches the same deck color as the superstructure. The cavalry brown is a bit more red than the flat red primer. I did not mask the blue. I just made sure I was spraying from angles the would not hit the blue. It helps to use a 0.7mm nozzle with only 20 psi. That helps minimize overspray.
Since this model is too big for my spray booth, I painted it on top of the booth and wore my respirator.
With most of the grunt work on this model done, now the fun begins as I add details and weather it.