Disclosed is a process for preparing an ink jet printhead which comprises: (a) providing a diaphragm plate having a plurality of piezoelectric transducers bonded thereto; (b) aligning an electrical circuit board having a fill joint with the piezoelectric transducers and temporarily attaching the electrical circuit board to the piezoelectric transducers, thereby creating a layered structure having interstitial spaces between the diaphragm plate, the piezoelectric transducers, and the electrical circuit board; (c) applying a thermoset polymer through the fill joint and allowing it to fill the interstitial spaces via capillary action; and (d) curing the thermoset polymer to form an interstitial polymer layer.