The model steam locomotive mechanism is more complex than that of other models mainly because of its various rods, valve gearing, screws, rivets, etc. All of these little components add to the realism of the model. One of the questions that many steam modelers have is whether to paint the mechanism, with rods and valve gearing, or leave it as is. My answer on this is, you should finish your model in the way that you want it. That is one of the wonderful aspects of this hobby. For those who desire to paint the mechanism components, I have offered some tips on how I do them below. There can be some variations to this process. Some like to paint the mechanism with the loco fully assembled and running. I like to disassemble the mechanism from the loco to reach every part of the linkage and to avoid getting paint into the motor. So, I'm starting the steps below after the mechanism has been removed.
1) The first step is to check all of the rods, valve gearing, and linkage, checking for proper alignment and rod screw tightness. I like to make sure the rivets are in good condition and have proper tightness as well. This step is important as any adjustments, etc. after painting could leave marks or scuffs.
2) Hook up the electrical leads to the motor and allow the wheels to spin while holding a piece of fine sandpaper to the side rims of the wheels. Be sure to get all of the area thoroughly as this will ensure that the paint adheres to the wheels.
3) Next, remove the motor, allowing the wheels to spin freely. Check one more time for proper alignment of all the components. Using a soft metal-bristle brush, go over the wheels, rods, and linkage carefully to remove any foreign material. Soft steel wool will help remove rust spots and rough areas. Next, using a small soft brush dipped in alcohol, go over the entire mechanism again to clean any grease, oil, or debris off of the areas. If steel wool was used, check to see that all of the dust is removed during this step. If not, rinse again to clean it all off. Allow to dry thoroughly (I use an air gun to dry the unit and blow off any final debris).
4) Place the mechanism upside down in the painting area and begin painting. I like to use a very light spray, turning the wheels to different positions often. Switch to the other side and do the same. "Dusting" on several light coats is what you are after here. Avoid spraying too much at once.
5) After the paint is cured, I turn the mechanism right side up and lightly paint again, applying paint to the areas missed and lightly reapplying it to the entire mechanism.
6) When you are satisfied with the finish, reassemble the motor, boiler, etc. Turn the loco upside down on a soft surface and hook up the electrical leads. With the motor spinning the wheels, carefully clean all paint off of the wheel tires. I use the corner of a thin, soft cloth dipped in paint thinner for this. You can finish with a super fine sandpaper to polish the tires if needed. I use 300 super fine polishing paper for this and only if absolutely needed to polish the surface. Do not use anything coarser, as scratching the wheel surface can actually cause it to retain dirt faster and reduce the electrical contact.
Normally, this will be done in conjunction with painting the entire locomotive. If not, you will want to be sure and use a color that best matches your loco. If desired, weathering of your choice can be done after the mechanism is painted.
Yardbird Classic Trains