Magnesium oxychloride cement is formed by mixing a magnesium chloride brine solution with a magnesium oxide composition in a selected stoichiometric ratio of MgCl2, MgO, and H2O that forms the 5 phase magnesium oxychloride cement composition. The metal detector has a phase shift circuit to phase shifting a sensor output signal by a known amount and a switch operating in synchronization with an excitation signal of the sensor for sampling the amplitude of the phase shifted output signal. To keep adhesives and encapsulants required in the assembly of the inkjet printer printhead out of the critical ink channel area near the orifice holes, fluid accumulation channels are ablated into the flexible polymer tape in a strategic location between the adhesive bead and the ink channel.