Once all the scrap lumber has been removed from the building and the majority of the area cleaned, it’s time to fill all the countersunk sheet rock screw holes or anything else that needs to be smooth - especially on the running surface of the track. This is best done using automotive Bondo – although some carpenter/builders prefer wood putty.

Carefully mix whatever material you choose, using a 1" to 1.5" flexible putty knife. Mix only a small amount and do 8 or 10 screw holes at a time. Follow the manufacturer’s recommendations to the letter…too much hardener and Bondo will set up too quickly…too little hardener and it won’t harden correctly. Many times it might be necessary to make two applications of Bondo to cover any screw holes so they are completely smooth.

When thoroughly hardened, use a vibrating sander and remove any excess. The light "pinkish" color should be round and just cover the screw, not showing any more than is necessary for a smooth surface. After all Bondo filling has been sanded, vacuum the dust. Prior to painting the racing surface and side retaining walls, fold over small (4" wide) strips of 400 grit sandpaper and sand both sides of the slot on each lane and rub it across the braid recesses. There should be no sharp edges or "burrs" on any lane or braid recess.

Vacuum the slots and track surface one final time, then using Tacky-Mac wiping cloths, wipe the entire surface down to remove all remaining dust particles. You are now ready to paint your layout.