My BLI Mikado has shiny valve gear. While this looks cool when running, it is not the way a prototype rod system looks. I hesitate to use paint as it may clog the tiny pivot points.
Depending on the railroad, some steam had machined metal rods while others were painted. Try dry brushing the face and top of the rods with Dullcote or another flat clear. Or apply some dark colored pigment powder to simulate road grime. Use the self adhering variety so you can skip the Dullcote application.
it is a little pricey depending upon your source but you might try neolube. i know micromark sells it but they are proud of a 2 oz bottle.
charlie
One word. Neolube. http://www.micromark.com/neolube-2-fl-oz,8383.html
Andre
I’d go for Neo-lube also, but you can paint them too. You can take a toothpick and apply oil to the moving parts before painting, as paint won’t adhere to the oil.
Try a sharpee marker. Not as thick as paint and sticks to everything and is very controllable.
Pete
If you can clean the rods first, just about any paint would work, but it would take a deft hand for it to look ‘right’. The paint won’t adhere where lubes have migrated, so you’ll have to clean the rods, preferrably by disassembly first. Probably Neo-Lube is the best bet if you want a quck 'n dirty that will work even around the pins where the levers have been lubed.
As stated above, many rods have shiny metallic edges with darkened recessed webbing of sorts. It would be cool if a steamer in scale had finely crafted rods of that nature. A very fine micro-brush with Neo-Lube or a dark grey acrylic (clean rods!!!) would work in that case so that the machined edges of the rods could remain shiny and metallic.
Here is a photo of the Royal Hudson, Ex CPR 2860. Notice how the outer expansion link rail is greyed or blackened in the webbing, and how the main and side rods are similarly appointed.
Crandell