The need for physicists to work with others outside of the discipline of physics has become more prominent due to the growing necessity of interdisciplinary subjects and careers. While this need exists, there are few opportunities for physics students to gain collaborative experiences and skills. This study looks at how a community of practice formed within an informal physics program that was designed specifically to bring undergraduate physics and graphic design students together to create an aesthetic physics teaching tool. Throughout this 10 week summer project, we collected qualitative data in the form of interviews and written responses from a team of four undergraduate students, observed meetings, and interviewed the project co-developers. These data record the students' and co-developers' experiences as they work together to develop a public engagement project aimed at combining physics with art and design. Using an operationalized Communities of Practice framework to analyze these data, we are able to explore the formation of a Community of Practice and better understand how developing informal physics programs can foster a community of practice environment.