I have made woodchip loads several times using a method that works very well for me. I work in a woodshop (making wood windows) and what I do, is to take and rip strips of fir stock to fit the bevel in the interior of my woddchip cars-mine are Walthers' Gunderson ones and the inside is beveled. Then I rip the upper side of the piece to about a 10-degree peak, then I cut the pieces to length. Note that there is a bit of cut-and-fit involved, but this works well. Then I take either hand sandpaper-or a power sander-to round the sharp edges of the peaks and randomise the shape of the pieces. Then with a liberal application of carpenter's glue, I sprinkle sifted sawdust over the pieces. Repeat as necessary to cover any thin spots or gaps and you will have, in my opinion, very good woodchip loads. I use fir, because that matches best the color of the prototype chip loads I see out here in Washington. I find that this is also a very good mass production technique because of its ease to do. Hope this helps.
Were I as good with computers as I am with carpentry, I'd post a photo or two, but, I'm not.
The only thing I could think of would be saw dust. Not the large chips, but the powder. Not sure how "in scale" it would be though.
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