I tried all sorts of methods to cover the seams of the cardboard. I tried spray glue and wrapping paper to cover seams, sanding the packaging tape seams, but none of these methods worked right. What I found to work and be reasonably fast was to first cover all the edges in packaging tape. Then use the spray primer on the tape. Once this is dry, use house paint to help conceal the edges of the tape. The paint gives it a texture that helps to conceal it. I used a standard paint roller to give it an even texture. I gave it two coats. Once all of these are dry, I applied a base coat of blue, and let that dry. Then I applied the silver. Afterwards, I used the masking tape and acrylic paints to add in all the decal effects. To save money, I cut the blue masking tape into little strips with my x-acto and ruler, since for stenciling, you don’t need that much. the less the better. It’s less likely to pull up and of your other painted details.