A seal assembly includes at least one primary seal, whose ends terminate in a modified air duct that is housed in a precision bore located at the ends of the primary seal slots. The air duct functions to seal the primary seal slot ends. A slot milled in the face of the air duct allows the primary seal to pass through and terminate centrally in the air duct bore. Minimal interference between the bore and air duct prevents cooling air from escaping the bore, completing the seal. Proper specification of the length of the primary seal in conjunction with precise location of the air duct bores allows for ample thermal expansion without loss of sealing. Axial clearance between the mating bores and air duct ends provides allowance for build tolerance, thermal expansion and movements between mating nozzles including movements between corresponding vane manifold portions.