Compressible Tank Seal

A method for casting a concrete wall having a tank seal therein comprising:

• securing a mandrel to a door of a form;
• placing a tank seal on the mandrel, the tank seal including
• a generally cylindrical main body having a first open end and a second end, the generally cylindrical main body having a first axially-extending portion extending from the first open end to an axial position intermediate the first and second ends, the first axially-extending portion having a first outermost diameter, a second axially-extending portion of a second outermost diameter which is less than the first outer diameter, extending from the axial position intermediate the first and second ends to the second end, and a radial ledge connecting the first and second axially-extending portions at the axial position intermediate the first and second ends;
• a wiper blade portion extending radially inwardly of the first and second axially-extending portions, from the second end of the generally cylindrical main body in a direction toward the first open end, terminating at a third end;
• an annular rib projecting radially outward from the second axially-extending portion, the annular rib being axially spaced between the axial position and the second end;
• and
• a web extending across the third end of the generally cylindrical main body, the web including at least one annular groove therein to facilitate removal of at least one circular portion of the web;
• advancing the door of the form toward a wall of a core in the form until the tank seal makes contact with the wall of the core;
• continuing to advance the door of the form toward the wall of the core, thereby exerting compressive force on the tank seal in an axial direction, whereby the radial ledge connecting the first and second axially-extending portions collapses so as to reduce an axial length of the tank seal;
• and
• pouring concrete between the door and the wall of the core.