A brazing fixture apparatus is disclosed for holding a heat exchanger core during a brazing operation. The fixture includes a generally rectangular frame including a contact member disposed on one side of the frame and a single lever extending axially along the length of the frame. The lever pivots from a first position to allow placement of the core onto the frame to a second position, in response to gravity, such that in the second position, the lever applies a constant compressive force on the core to hold the core together during the brazing operation.