My experiments today, maybe we can all benefit!
A piece of 3D print. But it could be anything, really.

I started by damaging a part of 3D print, just to see how that alter the effect.

I dilluted the car body filler with acetone before adding the hardening agent

Smeared it on
Here's the trick: Dab it with a large brush!

How it looks when dried:

Looks like sh*t but let's do something about that...
Now, it all comes down to how much you sand it!

Left lightly sanded, middle sanded a lot, right side untouched
Added some black paint...

After the paint dried

Added some brown paint as well

I love graphite pencils for this!

See how different the graphite sticks to different surfaces?

You can easily soften the effect

And the result of this experiment on real 80 year old German Panzer tracks:

Can you guess the track? All three? ;D


I must say for a first try I am very satisfied!