I have two Athearn streamlined passenger cars with the older metal trucks. I want to clean and repaint them to go with my newer Athearn cars. However, the metal trucks look to be grainy. Is this just corrosion that I can clean off with vinegar or the sort, or is this zinc pest? It might even just be a rough molding, I just want to be sure if I can clean it off.
Vinegar would tend to etch the zinc. I would scrub with a semi-soft brush and mild abrasive, a toothbrush and toothpaste comes to mind. Then a light coat of grey primer would even out the color so you can inspect it better.
Zinc Pest causes cracks in the casting. From your picture I would say they are just dirty, I don't see any cracks.
Yeah, if no swelling or cracking or brittleness, it's just oxidized/corroded on the surface. I have always thought the color of the old Athearn metal side frames looked good. I think they were blackened. Doug