Quoted from Mike Weston's site
"Use and Handling Instructions
Surfaces must be dry and free of dust and grease. Roughen smooth surfaces. Fill the mixing tube with strands of binder between two of the marker lines. For every square covered by binder add one small measure (one large measure for every two squares) of hardening powder and mix thoroughly using the spatula. Apply a thin layer to both surfaces and hold in place for approx. 15 minutes. No need to apply much pressure"
Good stuff too, I did my Micro Magic partially with that.