Starting your models: The base coat

Today I figured I'd talk a little bit about the different ways I paint my models. I often find it's best to start with a colored basecoat so you save a TON of time not having to brush it on slowly.
My father and I have had a spray booth for almost 20 years but we've never been really happy with the way the ventilation system worked and there was never really enough light. So this week my father and I swapped out the fan for an old motor from our solar heating system, and put in an OTT bulb and the result was nothing short of amazing!

I find that you can airbrush GW paints if you simply thin them enough. It's almost a 1:1 ratio but once you hit that sweet spot you'll know. Airbrushing allows you to put down a nice light coat without obscuring any detail. Since this is not precise work I'm using a single action airbrush.
Here you can see me applying Ultramarines Blue to a Predator.

As you can see the paint does go everywhere and there's even some on my fingers.

Here's a shot of the newly installed fan and light set up.

This shows why you want to have good ventilation, after 30 minutes this is what the filter looked like. Before we updated the fan I would usually be sneezing and coughing this paint for a few days after wards.
This is another method I use. If you can find a stick that is 1"x1" you can place your models in a checkerboard pattern on each side. This allows you to waste very little paint and catch much of the over spray on the model behind the one you're concentrating on. When using this method I use colored spray paints. For my guardsmen I went with Tamiya spray paints Desert Yellow.

Spray paints aren't as accurate as an airbrush so be sure to do this outside. Also some spray paints (like the Tamiya I use) doesn't like to be painted over so I have to seal all of my models with Krylon Matte Finish before I'm able to paint any details. I find I can usually get about 70ish models per 2 1/2 cans of Tamiya paint set up this way, if doing each model individually I'm lucky if I get 20 per can.

Using a colored base coat allows me to skip brushing the color into every crevice as the spray will go where you point it.

Properly thinned down I was able to put 2 coats on each of the following models with 1 bottle of Ultramarines Blue paint.

For those that can't tell that's 3 turret-less predators with removable side doors, 6 Ultramarines with Plasma guns, 1 Damoclese Rhino, 1 Land Raider Crusader, and not pictured is a black reach dreadnought with removable arms.

I find that with these 2 methods I don't usually need a primer coat and the paint seems to stay on the figures. The spray painted metal guardsmen don't chip too bad as they have the spray, the sealer, the basic paints, then another coat of sealer. While the airbrushed models usually have 2 coats of paint, basic paints, and sealer.