"Making" as an educational approach holds promise both for introducing mentors into STEM programming and for showing girls new pathways into STEM (Wittemyer & Gill, 2014). With its merger of cutting-edge technology and traditional arts and crafts, "Making" can help girls learn about electronics, robotics, metalwork, woodwork, sewing, and many other fabrication techniques. It can also attract mentors who have both technical expertise and personal interest in the creative aspects of "Making." This research-practice partnership focused on an afterschool "Making" program for high school girls. The article reveals promising practices for supporting mentors in STEM-oriented "Making" programs.