Mud FX

Mud and general filth on model AFVs has always been problematic for me. I usually go little further than adding a bit of dust and grime with paint, because it goes against the grain to cover up all the model's lovely detail.

However, sometime some really enhanced filthiness is called for.

This is a bit of experimental tinkering, using my old Airfix Mk.1 as a test-bed. I thought, what better to use to represent mud than actual mud? So, I went and scooped out a bit from the front lawn.

It's been thoroughly dried and baked to kill off any spores or anything living in there, and then pulverized in a cheap little coffee grinder I bought for exactly that sort of job. It could be ground even finer with a mortar and pestle, but I wanted to keep it slightly clumpy; to represent churned-up grass you could mix in some chopped-strand flock as well.

I mixed it into a loose, muddy slurry using Vallejo acrylic thinner (NOT the airbrush thinner), which is basically just a thin matte acrylic medium as far as I can tell. This binds the "mud" into a fairly tough, water-resistant layer when it dries. Then it was brushed over the tracks and dabbed around the bottom edges of the hull with a ragged old hog-bristle brush. The randomly clumpy consistency of the slurry, and the fact that it's ground much more coarsely than paint pigments are, keeps it from just looking like paint when it dries.

When it goes on wet, the "mud" is a dark brown, but it dries to the opaque colour you see in the dish here. Damp mud is darker in colour than dry, so I sloshed on a layer of my Magic Wash to darken it up again on the hull sides — I left the mud on the tracks untouched, because I wanted to see the difference. When that had dried, I dabbed on a little more of the dirt/thinner slurry further up the hull sides, where the mud would have dried a bit. You could probably do it in reverse — dab on the wash only where you want the damp mud — but the advantage of adding "dry" mud over the top is that it increases the textural effect of the dirt slurry.

Overall, I'm reasonably happy with the outcome, but it would have to be used judiciously I think. It certainly looks like dirt, which is unsurprising because it is dirt. But as I expected, it absolutely swallows any kind of fine detail, and the acrylic thinner is tough enough that it's not really feasible to remove. Possibly, using something like gum arabic as a binder would be a better idea; it could then be modified after it dried with a wet brush or cloth to thin it out or remove it, and then it could be set in place with the thinner only when one was completely satisfied with the effect.

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