Here's the structure of my board. I forgot to take pictures before this step but basically I cut wood trim into a box and put a 1/4" base. All was glued together with a hot glue gun. I then put pink insulation foam in and hot glued that to the bottom and sides. This creates a very sturdy and light base. I then took Spackle and filled the gaps.
After letting this dry, I decided it would be easier to put my brown house paint down before I added sand. That way pink foam wouldn't show through any missed spots.
A storm was brewing outside, so luckily my wife was around to help me put a layer of glue and sand down. I first sprinkled some course rock down then added playground sand. Dusted it off and quickly brought it inside before the rain.
I then went back over with the brown house paint. Since I didn't want to wait around forever I used a hair dryer to speed things along. Since it has been 15 years since I had enough hair to even blow dry my hair (or let alone comb it) it's good have my wife around for supplies!
The next step was a drybrush of a desert yellow style house paint, then finally a bleached bone color.
I then did two coats of a high gloss black paint around the sides. Just like my miniature bases, I prefer doing black rims around the bases. The high gloss allows me to handle the sides better as well. The added benefit of the trim is that it is curved allowing me to easily pick it up off of a table. Finally I'll add in felt pads on the bottom to protect the gaming surface.
I'll be posting pictures of the final army in its finished glory!