Hello Guys
Yes, the belt (or hand) sanding way is what we used for over 50 years to make the curved ends of Clerestory roofs from the stock roofs (with flat blunt ends) provided long ago by Walthers Company in O Scale ( and also in HO scales) . They even had a metal template for sanding the roofs and checking the proper curve shape. One trick I used to hide the rough wood grain from sanding in early years was to cover the entire upper roof including the sanded down sloping ends, with long pre cut sections of thin file folder cardstock. Its smooth and lends itself well to appearing to be canvas covering over the wood roofs which many older cars (railroad and streetcars and EL cars) had.
You can also carefully line-locate, and then press in the rivet lines and patterns to the undersides of these cardstock sections -- to replicate rivet patterns on the roof exterior. The finished painting looks great and no wood grain showing thru.
In more recent years (decades) I used auto body shop "red spot filler" BONDO filler on wood which was sanded -- even fine sanded - to avoid the tell tale grain --- this stuff comes in a red and white small (they have various tube sizes) tube and is pre-mixed... just squeeze it out, spread and smooth it, and let dry. Then very fine sand the remains to a glass smooth finish.
regards - Joe F
