From the book "Building the American Mandolin, by Johann D. Brentrup
You may do as you wish, but this is my recipe. First I dye the whole instrument with a mix of Trans-Tint yellow and honey amber in a water base. The yellow base and sunburst are applied with a very clean airbrush with the smallest tip. I have never applied any finish before dying the wood as it will only mask the grain. Sunbursts are started at the edge of the top and back by starting to apply a light dye made up of red mahogany, brown maogany and dark brown Trans-Tint mix.
Test the mix on some scrap wood before applying to the instrument. Here is a photo with the first coat of brown applied to the edge. You will have to experiment with distances from brush to surface.
As you apply more coats, the edge will begin to darken and blend more. After 3-4 coats, you can start adding a little more Trans-Tint to the mix and it will start to look like this:
Finally, you can add a couple of drops of black to the mix and only spray around the edges, darken to suit. Keep in mind that the sunburst will always look darker until you apply several coats of your preferred finish. As you perfect your airbrush techniques, you will be able to darken tiny areas where the grain will interfere with
the amount of dye that will be taken into the wood, especially the spruce top.
Here is an example of a very nicely sunburst F5 with the binding being scraped.
Hope this helps...open for questions.
