Mud

I totaly forgot to post the mud build up on the wheels. Time for some dirt. I used some sand, pigments and plaster to build op some mud on the wheels.I build it up in layers and the last layers are pigments only.

I used white spirit to set the pigments and when you are happy with the result you can set it with pigment fixer. 

After this you can add extra dirt/oil stains to it to make it more interesting. You can add some light washes, streaking or oils marks to it just as you like.