A method for assembling a turbine assembly is provided. Two sides of the U groove are each formed with a receiving groove to which a wedge flake is wedged. This composition can be applied to a suitable substrate to provide a negative-working imageable element with improved digital speed and good shelf life and that can be imaged to provide lithographic printing plates. at pressures in the range of from about 0 to about 500 psig for a time in the range of from about 1 to about 240 minutes to form thin wafers.