The dune on the starboard side is mostly done... eventually it will come up over the deck.
The first photo is the test bed. Orb on the left is drywall compound with a slurry of desert sand and "size glue" (that is a theater term for 50/50 white glue and water). The middle orb is aquarium sand, which is very wet but takes Tamiya spray color very well when dried. The right orb is drywall LiquiTex matte gel with regular sand applied.
Taking all that into account, here is the dune process... 1/4 spheres of styrofoam were placed with a "size water" soaked paper towel over the top. Drywall compound was applied, then the slurry of sand and size water which was smoothed. Over the top of that was the aquarium sand, which is very workable with water. The more you apply, the more you can smooth it out. After that, more size water was spritzed over the sand and dried aquarium sand, which is very fine, was piled up. Amazingly, a spritz of the size water held it in place. Tamiya spray color was applied and when I turned the thing over... NOTHING MOVED or fell off. I was pretty stunned.
Here is the result. As I said after I am done working it, the hull will be permanently placed, the gap filled and sand piled over the deck...
As always, your comments and criticism is welcome!
Thanks for looking!