First I disassemble the guitar, then I sand it down and prime it with a grey mixed from pro-color white, black and ultramarine (8:1:1). I mask those parts which are not to be painted. Then I take the same color, lighten it with white and thin it with water (1:1). Then I take a piece of plastic wrap and begin to apply and spread the paint. Proceed with dabbing movements, but don’t apply the paint too uniformly. The structure should have an air of spontaneity about it. You can do this by repeating the procedure with another grey (base color + 5 % pro-color Black + 10 % pro-color ultramarine). I gently go over the wet paint with a wet sponge, in order to reduce a few of the sharper edges. I wipe the three colors into one another, while at the same time smoothing the surface.
To make the concrete imitation even more interesting, I add some air pockets. For this I use the "Mural Structure" stencil. I put the template where I want air pockets to appear and fix it on the guitar with a bit of sticky tape. The color is my base color mixed with black and ultramarine (1:2:2). You can define the contrast to the background just as you like, depending on the desired effect of depth.
Once I am satisfied with shape and positioning, I can increase the depth a bit more. For this I need to position the stencil in a way that lies exactly on top of the air pockets I have already painted. Now I create light and shadow. Make sure that you stay true to the direction of the light source. In order to mix the shadow’s colour, add 5 % pro-color black together with 15 % pro-color ultramarine and 50 % water to the air pockets’ color.
To achieve a little more variety I’d like to simulate concrete slabs. For this I create a few lines using sticky tape. The coloring works just the same as with the air pockets. On the edges, you should watch out for the light source and for realistic light and shadows, again.
Here you can see the intermediate results of the guitar
To complete the design, I’ll apply a warning sign ("Caution! Electric current!"), which looks like it’s attached with rivets, using a stencil. I attach the stencil with tape, prime it with white and spray over it with pro-color canary yellow.
To protect those yellow areas that are not supposed to become black, I mask them after drying with the stencil used for the letters and the flash. That way, the letters and the flash will have sharp edges. I spray black in thin layers. This way I keep the color from running underneath the stencil.
At this point, I define the design even more clearly by adding a skull. Of course I have to watch out for the correct shape, color, light and shadow, again.
I spray a "Hard Rock" logo with transparent fuchsia red. Before the paint is dry I wipe over it a little unevenly, giving it an even more transparent effect.