First, and foremost, this base is going to use up a massive amount of Super Sculpey modeling clay. The material is easy to work with, cheaper than Green Stuff, and won't dry out, or set until I bake it. That means I have weeks to fiddle with it, and add detail before I run off to bake it. You can see the first few stone forms in the photo above, as well as the clear delineation between the little fired patch around the brass support post, and the fresh Sculpey.
Even with all of it's great features, I don't want to try to fire a 40m think chunk of Sculpey. It is too likely to crack, or just not cook all the way through, leaving a fragile, uncured mess. To mitigate that problem, I started gluing some cork tile to the base. The cork will serve as a firm filler material underneath the Sculpey. In the photo above, you can also see the band of Green Stuff that I added around the cork. The purpose for that addition is to make a smooth interface between the cork support and the Sculpey. With any luck, I will be able to remove the Sculpey in sections to fire it, and then return it to the base. I don't think that would have worked out well, if it was directly pressed into the rough texture of the cork.
At this stage of the build, I was keeping the big chunk of cork that goes directly under the dragon separate. My hope was to use it to create a removable part that could be re-mounted on a gaming base when the diorama was not on display. Clever sculpting would allow the rockwork to fit together snugly.
As I kept adding Sculpey, it quickly became clear that building the rocks around a removable central support would be a lot of trouble. I think it would be doable, but tricky. Fortunately, a friend from my local paint club suggested a far superior alternative: Make just the dragon removable!
I knew, from my past experiments with mounting ships for Firestorm Armada, that standardized brass rob and tube stock could be fitted together very nicely. Rummaging around in my parts supply, I picked out some 1/16" bass rod stock to glue into the dragon's feet. I had rejected the 1/16" inch stock as too flexible for mounting the night, but it's more than enough to handle the light weight Bones material.
With the pins set into place with some super glue, I cut two lengths of 3/32" brass tube to form the female end of the pairing, and glued them down into the display, anchored in the wooden base. I glued the last pieces of cork to the base to provide some sturdy support for the brass, but, if the whole arrangement works, Narthrax will be easily removable from the display, even after painting.
I left the pins quite long. It will increase strength, and reduce wobble, while the Dragon is on display. Thanks to the flexibility of Bonesium, it is fairly easily to align the feet with their fixed positions, without having to precisely machine the whole structure to strict tolerances.
In the end, you can't even tell the structure is there!