Salt weathering Warhammer 40K terrain pieces

A few years ago I saw a tip in White Dwarf about salt weathering a tank. It is an effective technique to get a 'rust coming up through the paint look'. I thought it looked very interesting but as I was busy painting Tyranids at the time I did not have much of a chance to paint rust. My current project with rusted space ship (or industrial) terrain gave me a chance to grab the old White Dwarf and look up how to do this:

Oh no! Rusty surface upset Genestealers! You don't want Genestealers to be upset! Or do you?

But even though I keep my old White Dwarves neatly in cardboard storage boxes I couldn't for the life of me find the article. As the next step I started searching for the article online where (along with the White Dwarf I should be looking for) I found a rather nice hint on Warseer "Some really nice articles in there, the salt weathering one, although instruction on that can be found for free on any plastic modelling forum on the net..." After I was done smacking my forehead I looked up one of those free tutorials. As it was written by a military modeler it contained rather a few more 'be precise' admonitions then I usually keep to while modelling. So here is my slightly more whimsical Rossian (Bob) have fun and relax style salt weathering tutorial.

You need

• Something already painted with rust colors;
• Table salt;
• Water;
• An airbrush.

Step 1 - Just add water
Coat the object that will have rust showing through in rusty colors and proceed to make it wet (with water to be very precise). At this point you can decide to leave large areas dry, these areas will not have any chipping effect later on.

Not pictured: the water I used to cover this storage tank.

Step 2 - Throw salt at it
Grab table salt and throw it on the wet surface. As a future reference to myself I should consider covering the surroundings of the object as I'm still wiping salt remnants of the rest of this model right now.

Don't use fancy salt, just plain boring table salt. 

Step 3 - Wait 
Let the water dry. The salt you threw on will stick to the surface.

Salt dried to the surface of my storage tank.

Step 4 - Add color 
Grab your airbrush and carefully paint the surface including the salt. Use about as low a PSI setting as you can manage to avoid blowing off the worst of the salt. As I type this, I suddenly realize a quick way I could have used to rid myself of the unwanted excess salt on the bottom. I used several coats and added a slightly lighter green to the top as the darker green dried (colors used in the pictures below Vallejo Model Air Cam Green and Vallejo Model Air Light Cam Green (or River Troll Skin Color as I like to call these two).

Are we green?

I said: are we green?

Supergreen!

Step 5 - Wait 
It's almost the same as step 3, but now you just wait for the paint to dry.

Step 6 - Wash the surface 
When the paint is fully dry take a wet rag or sponge and carefully wipe the surface you painted. The water will activate the salt causing it to fall off taking bits of paint with it. In the end your model should look something like this.

You've got to love the ease with which this effect is achieved.