This is a tutorial written especially for Axiom & Just John (and anyone else who's interested too for that matter), as they were too impatient to wait until I returned home from my holiday :P
There won't be any pics with this one guys, sorry, but I'll try my best to describe the process.
1. Pigment - Rust & Dark brown
2. Acrylic paint - I used Vallejo Rust & GW Scorched brown
4. Oil paint - Black & Dark brown
5. Two old brushes, size 1, or there abouts.
6. Two small cups - to mix paint in.
7. One largish soft bristle brush.
8. A small dish that won't get eaten up by benzene i.e. glass, ceramic or metal.
9. Liquitex Matte Varnish.
Step 1. Prepare the surface as per usual for metal (prime black, drybrush boltgun metal).
Step 2. Clear coat it with gloss varnish. Let it dry completely before continuing with the next step.
Step 3. Into one of the small cups mix equal volumes of rust paint, rust pigment & water together.
Step 4. Repeat step 3 for the other colour.
Step 5. Using an old paint brush for each of the paint/pigment mix, apply the paint in a random fashion, using a stippling action. Make sure to wipe most of the paint off "drybrush style" before you apply it though. Make sure to use only one colour with each pass.
Step 6. Repeat with the other colour after the first coat has dried a little.
Step 7. Keep going back over it, alternating between the colours, until your satisfied with the effect.
Now, a few clarifications about this technique;
About the pigment/paint concoction, I do this for a couple of reasons, the first is that I find that when I use pigments on their own I end up with more on my painting desk than on the mini. The other reason is that I can control (with the brush) how thick/thin I want to apply it. Rust is an organic process -it should look irregular. I find that it looks a hell of a lot more convincing to me when I use this technique.
Once its all dried then I rub the rust back in places that wouldn't get a chance to rust up (such as rungs of ladders, handles, areas of foot traffic etc) with my finger, to expose the metal underneath. If I can't get into these areas then I drybrush them with boltgun metal to achieve the effect.
OIL STAIN RECIPE:
For this part I followed a tutorial over on Buypainted. The only thing I did differently was to go nuts with the oil paint, whereas he was only after small oil stains, I was wanting a more "oil leak" & worn out effect.
If you've never used oils before I'd strongly suggest that you give them a go. They weren't that difficult to use and they took a while to dry out so I had ages to work with them.
After I allowed this sucker to dry overnight I hit it with matte varnish. I didn't use Testors Dullcote because it's just too damn matte! Oh, and I sprayed it on too, as brushing it on would only encourage the paint & oils to smear.
And that's it really. If you've got any queries or questions about the process I used then ask away and I'll do my best to answer you.
Bye for now.