Studies on physics identity have shown that it is one of the main factors that can predict a person's persistence in the field; therefore, studying physics identity is critical to increase diversity within the field of physics and to understand what changes can allow more women and minorities to identify with the field. In this study, we investigate informal physics programs as spaces for physics identity exploration. These programs provide unique conditions under which to study physics identity development along with other identities. Informal physics spaces allow for voluntary engagement, as well as elements of agency and autonomy within the exploration of physics. Thus, these spaces allow an identity to form outside of the constraints traditionally found in academic settings. In this work, we operationalized the community of practice framework to study the development of physics identities within university students who facilitate informal physics programs. We present the stories from two physics graduate students out of our sample to provide a context for testing the feasibility of the extended framework and to identify how experiences within an informal physics program can shape physics identity development. This paper presents the operationalized constructs within the community of practice framework, how these constructs are applied to the narrated experiences of our participants and highlights how we can use this framework to understand the nuances of physics identity development as well as the factors that can influence that development. Studies on physics identity have shown that it is one of the main factors that can predict a person's persistence in the field; therefore, studying physics identity is critical to increase diversity within the field of physics and to understand what changes can allow more women and minorities to identify with the field. In this study, we investigate informal physics programs as spaces for physics identity exploration.