I used the salt technique bud,primed the parts in a rusty colour then i matte varnished them after it had dried,then i used an atomiser and lightly misted the parts with water then sprinkled salt on,let that dry off then i top coated over that,just a couple of light coats of paint,let that dry then just brush it off! I left it for a day and i then went in with the sponge and added some more rust effects then gave it a light wash! Hope that helps man