For the Crucible Principate Army Project, you may recall that Minidragon 
of Studio Mini-Dragon painted the prototype figure for the light cavalry, and then Old Guard Painters followed the pattern to paint the remaining figures of the unit.
And now that the models were back at TMP, it was my job to base the new arrivals.
I decided to experiment with Gale Force Nine's cavalry bases, which are made of a rubber-like magnetic material.
As you can see in the photo above, the bases are 25mm x 50mm, 3mm tall with a slight seam down the sides, have a slot punched into them, and are topped with a rough texture. The material is thick enough to be stiff, but still have some flex to it.
The horse models, on the other hand, had a somewhat complicated connection to their mounting bar:
The bar was also too long to fit in the base's slot:
My solution was to remove most of the bar - leaving part of it attached to two hooves, and a third hoof completely free so it could be posed more naturally.
I then put some tape on the bottom of the base, to prevent me from pushing the model too far through the base and out the bottom side. With some careful bending and a little pressure, I was able to insert the bars into the slot. When they were in place, I cemented the connection with superglue.
Next, I wanted to fill or cover that slot, but wasn't sure what to use. Since the base had some flex to it, I was concerned that if anything caused it to bend, any filler would crack and fall out.
What I chose to use was Liquitex Modeling Paste, a material found in the art supply section of the store. It is essentially a gel that includes marble dust. I used a hobby spatula to apply the paste to the base, scraping the top so that it was level.
When this was dry, I touched up the base with brown paint (I had already basecoated it), and let it dry. I then applied Noch Grass Glue and flocked the base as normal, finished with a coat of Krylon Matt as a sealer.
On some of the bases, you can see a slight indentation where the slot was - I probably should have gone with a second coat of the paste, to compensate for shrinkage as it dries.
Do the magnetic bases work? Until I figure out a better storage solution, I currently have much of the Crucible Principate army stored in a cardboard box, floored with a sheet of FlexSteel (a rubber-like sheet that is attracted to magnets, and is adhesive-backed - mine were custom cut to size by Litko). The cavalry sit very firmly in the box. So firmly, in fact, that I have to remember not to lift the figures by their riders, or he might pop off his horse! (Lift by the horse, not the rider...)
I was also concerned that the bases might end up being not quite flat, which would affect their magnetic adhesion, but this proved not to be a problem.