Some of you might remember this photo from when I first posted my Triarch Stalker conversion showing that the model is roughly the same size as a Dreadnought walker. For ease of play and for consistency I wanted to base the Stalker on a 60mm base, but unfortunately the legs stick out slightly to far for it to fit. This left me with 4 options, to play without a base (like a Defiler), to custom order a 65mm base, use the large oval base, or to bulk out a 60mm base so that the model can fit on it. I chose the last option, and I will show you how I "stretched" a 60mm base to fit the model.
I started by gluing bark chips to 60mm bases so that they slightly overhang the base in places were the legs of the model need to attach. You can find bark chips at any store that sells landscaping supplies, and the bark's texture will make convincing large rocks. Then I filled in between the bark chips with wood filler to make a continuous surface that had the "rocks" erupting from it. I used wood filler because it was what I had at my work station, but you could use any kind of self hardening spackle. When the wood filler was set I glued my basing mix of sand and gravel (the grey and white stuff in the photo) over most of the filler to create a textured surface.
Here is the bottom of one of the bases so you can see how the bark chips stick out past the footprint of the base. This is how I create the room I need for the model to attach. You might also notice that this is not a GW base. A couple years back I ordered about 50 60mm wood cut bases and I have still not used them all.
Here are the bases painted to match my Necron army. This is not the most flattering paint job for these bases, but my army's bases have a barren black ash waste look that these needed to match.
My two Triarch Stalkers standing on their new bases, which now accommodate their long legs. Now all I have to do it paint the models and pin them to the bases. The same technique I used to make the bases can be used on larger surfaces to make difficult terrain or great looking hills too.