Instead of using a regular spray primer, a paint and primer combo spray forms a harder shell of paint around the tube I like to use white or grey, but use whatever fits your painting style or color scheme.
Spray a coat and wait until dry. You may notice some of the cardboard tube has particles showing. Take a light sanding pad or scouring pad and sand the particles off. At this point, you can add another coat or continue to painting the tube.
If you want to paint a secondary color after the base paint has dried, take a tape measure and mark the tube wherever you want to place the pipe rings.
Next, apply some painters tape around the sections you want to remain your base color. Once you place the pipe rings on the tube it will cover any odd masking that may have occurred.
Now spray whichever color you want and let dry. I like to use red for an industrial feel. You can do this with a spray can, airbrush or by hand. From this point you can complete the rest of the painting on the kit.
I recommend painting the majority of the kit before you complete the final assembly.
