The molten exterior surface portion of a hot dip galvanized steel strip is solidified after the strip is withdrawn from a bath of molten zinc by spraying finely divided particles of a liquid nucleating agent for initiating solidification. The particles are sprayed into an electrostatic field alongside the strip. The particles are initially directed along a path which avoids impingement against the strip. However, the smaller particles are attracted to the strip under the influence of the electrostatic field, to initiate solidification. The larger particles have a momentum along their path large enough to resist the influence of the electrostatic field, thereby permitting the larger particles to continue along a path which avoids impingement. This minimizes the formation of undesirably large spangles and an undesirable surface appearance on the strip.