Well, I'm sort of joining in this weekend. I say that because some months back I had an idea(and should have gotten what I needed then, but time was short). I had an idea to make my own coal loads for my Lionscale B&M Hoppers.
At work, one of our vendors is always sending in this foam as packing with their stuff and I thought this would be great to pop as a base for making carloads. I figured to cut it to size, shape it, spray paint it, then work on gluing the coal to it. I had also thought of making a jig to pop the foam in when gluing the coal in so I would have control of a potential mess. I have to wait until I can get stuff. Any thoughts on how to make this work great?
Depending on the style of coal load, you can use my method of whatever material you choose, (real coal, Black Beauty sand blast grit, or whatever other material you deem suitable, and get a cheap plant mister bottle, and a quart of water base urethane finish. You will need some way to keep the foam flat once you've cut it to size. Spray the foam with urethane, then sprinkle a layer of the coal material, starting around the border, then fill the inside. Spray again with urethane, and begin building the middle up. Some prefer individual piles, a mounded load, or a continuous pile, or humped load. Repeat until you have the desired profile, and let dry for a few days. After the load is dry, use a file in a downward motion to remove any material that may protrude beyond the surface, and test fit. I posted a video quite some time ago showing how I make my loads under my screen name "rail". If you can't find it do a youtube search under Don Kane Jr "making A Coal Load. Just use caution when inserting and removing the loads, as the foam is flexible, and could damage the load. I use 1/4" luan plywood, and legs at the ends as needed. Each hopper is different, and requires different means to fit the car.