Delayed opening fluid communication valve

A method of manufacturing a well bore tool, comprising:

• forming a first component configured to connect to a casing string;
• forming a second component configured to connect to the casing string;
• forming a mandrel to be disposed between the first component and the second component, the mandrel having a plurality of ports;
• forming a housing to be disposed outside of the mandrel, the housing having a plurality of ports;
• forming a piston to be disposed between the mandrel and the housing and configured to move in a first direction from a first position that forms a barrier between the ports of the mandrel and the ports of the housing to a second position that is adjacent to the ports of the mandrel and the ports of the housing;
• and
• forming a dissolvable seal configured to dissolve when exposed to a fluid to cause a force to be applied to the piston.

A casing valve, comprising:

• a first component configured to connect to a casing string;
• a second component configured to connect to the casing string;
• a mandrel disposed between the first component and the second component, the mandrel having a plurality of ports;
• a housing disposed outside of the mandrel, the housing having a plurality of ports;
• a piston disposed between the mandrel and the housing and configured to move in a first direction from a first position that forms a barrier between the ports of the mandrel and the ports of the housing to a second position that is adjacent to the ports of the mandrel and the ports of the housing;
• a dissolvable component configured to restrain the piston in the first position and to dissolve when exposed to a fluid to increase a lateral force on the piston;
• a first o-ring disposed between the housing and the mandrel at a first outer diameter;
• and
• a second o-ring disposed between the housing and the mandrel at a second outer diameter that is different from the first outer diameter.