Liquid metal technologies are progressing at an increasing rate, opening up new capabilities, applications, and functionality at smaller dimensions. Most composite and thin film printed conductors must be geometrically engineered to tolerate excessive strain and remain conductive; however, liquid conductors take the volume of their encapsulation. Gallium specifically is of interest here as it forms its own insulating casing that allows it to be patterned at fine features and to generate stable colloidal suspensions used as inks for printing. Additionally, liquid gallium alloys are ideal for many of the extreme environments in which flexible hybrid electronics are being asked to operate, to include extreme mechanical loads as well as extreme cold and space conditions. In this talk, I will discuss the work done at the Air Force Research Laboratory within my group to understand the fundamental nature of gallium alloys used for stretchable electronics and how we have designed them to be used as a drop in replacement for more traditional printed electronic inks (e.g. silver, carbon) to be processed using screen printing, blade coating, extrusion, and material jetting techniques. While it is fairly straightforward to generate suspended gallium alloy particles in solution, the work that our team has done to engineer the surfaces of these particles, understand the thin oxide shell growth dynamics, control the oxide composition, and correlate these properties to mechanical properties that effect the final mechanically sintered conductive traces will be discussed. A few select applications will be briefly discussed, including soft electrodes for long term physiological monitoring, actively heated textiles, and stretchable data cables utilized in soft robotic inspection tools.