Why do I get streaks or bands in my spray pattern?
Streaks in the spray pattern, especially heavy bands along the outside, are an indication of low pressure at the tip. Turn up the pressure with the control knob until these bands are eliminated. If the sprayer is already at maximum, you may have to use a larger diameter hose, or shorten the length of the hose to reduce the pressure drop. Also, make sure any paint filters in the system are clean, because a pressure drop can be caused by a clogged screen.
Sprayers are rated for a maximum tip size. Using a tip that is larger than the maximum size, or using a worn tip, will also cause low pressure. The tip should be the correct size for the type of material being sprayed.