It is always a good idea to make sure your screen is completely clean before starting a new print. Use Mesh Prep Gel (see on website) to degrease monofilament polyester mesh fabric.
Draw out your design on a piece of paper, place beneath the screen and trace the image onto the screen mesh with a soft lead pencil. Stir the screen filler to a smooth consistency before applying with a paint brush to the areas not to be printed. Allow to dry thoroughly in a horizontal position, bottom-side up, before applying the flood stroke.
Screen filler can also be used in conjunction with Speedball Drawing Fluid. The drawing fluid acts as a mask so that Tusche–resist or “positive method” of screen printing can be achieved.
Trace your design onto the screen using the method above, and paint over the areas of the design that you DO want to print through with drawing fluid. Be careful to fully block out the entire area. Leave the screen to dry in a level, flat position and make sure nothing touches the areas covered with drawing fluid.
When the screen mesh is completely dry, spoon the stirred screen filler onto the screen and over the design painted in drawing fluid. Use a squeegee to apply an even coating over the entire screen, in one pass. Multiple passes of screen filler will dissolve the drawing fluid.
Put the screen to dry in a horizontal position making sure nothing touches the fabric.
It is important that the screen filler dries completely before spraying with cold water on both sides of the screen where the drawing fluid was applied. These areas will wash out and leave exposed parts of the screen for ink to flow through them. Areas of the screen that remain slightly blocked can be scrubbed lightly with a small stiff brush on both sides. If necessary you can use washing soda dissolved in warm water but do not use hot water during this stage.
The screen is ready to use when it has been allowed to dry in a level position, bottom-side up.
You can see these, and many other, Screen Printing products on the George Weil website.