Rusty iron plates are 1/10th the weight of a normal iron plate, and rusty gears are 10x heavier than normal gears.
Notably, this means shipping rusty iron plates is significantly cheaper than shipping normal plates, as well as cheaper than shipping many other iron based intermediates.
Thanks for the report. I've hardcoded them to the correct numbers. I would prefer a less brittle approach, but the formula for Factorio's item weight calculations are undocumented. Let me know if you spot it.
