I built this load to represent a collection of steel H-column beams. These were a bunch of Plastruct parts leftover from an N-scale bridge kit that I bought a long time ago. I cut them in half to about a scale 32 feet in length. This is for S-scale, but the same idea can be applied to other scales as well. I set out to make them look like shiny metal, so I spray-painted them with gloss metal spray-paint (in a can). This went OK, but not great. Then I ran across the article titled "Essential Freight Cars: 26 - Freight Loads for Gondolas" by Ted Culotta in the December 2005 issue of Railroad Model Craftsman. This article covers the construction of several different types of loads. He suggested that the steel material be painted with a weathered black. I brush-painted Floquil's Grimy Black instead. The results are seen in this photo. Some of the shiny "metal" paint can still be seen, but I think that adds character.
The first construction steps are always the most challenging because they lay the foundation for the entire project. The wooden spacers are a scale 4"x4", and were cut to length to match the interior of the target gondola for which the load is intended. I used the ruler to make sure the boards were approximately equidistant, and then used a metal weight to make sure each board stayed perpendicular to the first steel beam as I applied superglue to attach them.
After the bottom boards were attached to the first beam, I then superglued another four beams to the bottom boards. I applied some Bragdon Enterprises weathering chalk to represent the rust that happens as soon as steel is exposed to oxygen.