I have several Athearn Dash 9 locos that have the ditch light castings mounted on the pilot. I have installed operational ditch lights on some units where the prototype had the pilot mounted light, but I have several where the prototype has them mounted on the anti-climber.
My question is what is the best way to make the holes disappear where the original casting once was?
The best way is to fill it and then file or sand it. The only problem is that you’ll have to remove all of the applied details in the area and repaint the pilot once the holes are filled.
The standard way to get rid of holes in plastic is to use an old sprue, larger than the original hole. Heat it (I use a match or cigarette lighter) until it softens, and pull it apart until it’s smaller than the hole you’re trying to fill. Let it cool, and when rigid again, cut it at the narrowest point. insert it into the hole, and glue with a solvent-type cement. when solid (wait about a half hour), trim off the excess on both sides of the hole with flush-cutting pliers or a sprue cutter, sand/file flush, fill as necessary with your favorite filler.