XR-12 Air-Dry Premium Leather Filler ThickXR 12 is a new, high performance air dry filler designed to tackle deeper cracks in leather. Its extra thick viscosity makes it ideal for leveling out other air dry fillers, providing an extremely durable and flexible repair. After the filler is fully dry, simply sand lightly with 600 grit sandpaper and apply a texture using Grain X spray grain or Texture Paste. If needed, use XR 10 to fix any pinholes or achieve a smoother finish before adding color.