Joe's Model Trains Co.
Rusty Rails Custom Acrylic Paint - 2 Ounce Jar (For Rusty Rails Painter Tool)

Shale
Walthers Part # 350-106, p. 832 Walthers 2012 HO Scale Reference
A scale, $6.95, currently in stock at Walthers

 
Flat acrylic enamel paint delivers a smooth flow with good adhesion to bare metal. Colors can be blended together for a custom look. Designed especially for Rusty Rails Painter #350-101 (sold separately).