I get a lot of questions on how to use pastel powder for weathering props, in this case it started out in helmet painting thread on this board. So here's a small tutorial on how to use the stuff! Thanks goes out to "Ttef abob" for hosting the pics!
Pastel weathering is perfect for almost every project where you normaly would use an airbrush, however, it looks much more like real dirt and IMO you have much more control. Pastel comes in chalks in all colors and you should be able to get them in any art or hobby store. The correct name is "Dry pastel" and you want them as soft as possible, but you DO NOT want oil pastels, that's something completely different.
So how do you apply it? Well you have to grind the chalk into fine powder, I just rub them against the sharp edge of an exacto knife but you could probably use a sandpaper too.
Here's what the chalks looks like.
Now here's where the fun starts! First of all make sure the surface you are going to weather is painted with a flat paint, it won't stick to a gloss surface. Take a soft brush and pic up some powder and gently brush it over the paint job. You'll be able to use it just like an air brush, press hard and it will get darker, or reversed if you just want a shaded effect. You can also apply it with a rag, q-tip, sponge well probably anything that comes to your mind, just experiment and I'm sure you'll come up with a lot of different effects!
Here's a picture of different weathering effects.
1. Basic air brush effect. Applied with an soft brush.
2. Yellow and red/brown dabed on with a Q-tip.
3. Heavy weathering. Dabed on with a cloth.
4. Blaster burn or something like that All techniques used.
The best thing about it is that it's "alive" untill you seal it so you can always smooth it out, make it darker or whipe it off with water (probably won't get 100% clean again on a light surface though) When your happy with your weathering you have to seal it so it won't smudge when you tuch it. You can use any clear coat you want, flat, gloss or satin. After the clear coat has dried its 100% permanent.
So why use pastel instead of an air brush? It's easier to use, you won't get that cheap airbrushed effect that always screams "airbrush"! Applied right this stuff really looks like real dirt! Perfect for shading the base color on a Fett helmet!
Here' a link to a tutorial for my ROTJ helmet. All the shading of the red visor, dome and cheeks was done with this technique. Please not that my words have been edited (by my recuest by the owner of the site). You can clearly see the weathering effect on the dome in picture 10 (it was applied with a soft brush).
I know I'm not a master when it comes to writing tutorials in English but hopfully you got some parts of it! If you have any questions please post here and I'll try to answere them as good as I can.