  Electrostatic patch potentials give rise to forces between neutral conductors
at distances in the micrometer range and must be accounted for in the analysis
of Casimir force experiments. In this paper we develop a quasi-local model for
describing random potentials on metallic surfaces. In contrast to some
previously published results, we find that patches may provide a significant
contribution to the measured signal, and may render the experimental data at
distances below 1 micrometer compatible with theoretical predictions based on
the Drude model.
