  In this paper we report on some new results concerning the behavior of forces
between two equal circular electrodes with finite thickness. We show that for
close electrodes different scenarios can result, depending on the thickness and
on the ratio of charges on the conductors. Attractive or repulsive forces can
appear depending on the parameters and on the separation of the electrodes. We
give a unified description of cylindrical systems using an high precision
method based on a Galerkin expansion and we check our results with a quite
sophisticated boundary element method (BEM). We perform a preliminary study of
a single cylinder (both full and hollow) to check the method and to improve
several existing results and compute some relevant parameters as the quadrupole
moment and the polarizability.
