I thought this was about as miscellaneous as you could get so I posted accordingly. And no I'm not sanding or sawing.
I've been looking at some online photos as reference for sawmill machinery and as one might imagine they are all caked with sawdust. The photos below came from: http://www.4helle.com/used_equipment.htm
So my question became how do I get this look without overdoing it? I'm experimenting with weathering pigments and Rembrandt chalk. When I built the machinery I went with the no paint look. I like the look of the weathered metal and I was unsure of my ability to credibly paint and chip the machinery. So...
For the first experiment I used a brush to pile on some AK North Africa Dust pigments. I didn't brush at all just stacked it on. Then I used odorless mineral spirits to set the pigments by dipping my brush and touching to the casting allowing the spirits to flow onto the piece and saturate the pigments.
After seeing these photos I think the color is close but there is a noticeable lack of variety in the sizes of sawdust. My second experiment is still drying. I scraped a rembrandt chalk stick and did the same process as above. I will post a pic once dry. I think it will have better texture but the color I chose is too dark.
I tried this method because I have noticed that chalks set this way have a nice matte finish and are fairly easy to remove if necessary. I will also try a very fine sawdust from my sander but am worried that if I need to reduce/remove the sawdust there will be an ugly glue spot to deal with. Also the texture of the sawdust may be to coarse for the stuff that would cling to the sides of the machinery.