Now that I have applied several coats of gesso I can start putting on the white basecoat. I use an airbrush to paint my animal carvings simply because I think it gives me more flexability when I want to blend in colors. That's not to say the same results cannot be acheived with a brush, and here again I say use what you are comfortable with. I am by no stretch of the imagination an expert at the airbrush. In fact I have only been airbrushing my carvings for the last several years and used a brush prior to that. There are still times when I will use a brush to add highlights or to touch up a small blemish. Below are the pictures of the bear after several thin coats of pure white have been sprayed. Once the white is done I will alternate with blending in some very pale yellow to get the color I want. 
 An adult polar bear is really not white after all, but a blend of white, light yellow and light grey colors. In fact in doing some research I've read that each individual hair is actually a translucent clear color, but I can't figure out how to paint that so I'll just make him white.

In these three pictures the white basecoat is just about done, I may have to touch it up here and there but for the most part I can start blending in my pale yellow.

Here I have started to blend in the pale yellow color and will keep switching between the pale yellow and pure white until I get the look I am after.