Thermal direct joining with hyJOIN® enables quick and reliable connections between metal and plastics without any additional material like screws, rivets or adhesives. Due to its reversibility, it facilitates the implementation of new repair and recycling strategies while at the same time minimizing the consumption of resources. During joining the parts are pressed together. At the same time, electromagnetically induced eddy currents heat the metal. The plastics softens in the contact area and binds to the metal surface during cooling. As plastics often adhere poorly to metal, the surface is structured or coated during a pre-process. Within the paper the hyJOIN® process is applied to generate media-tight connections between metal and plastics. To analyze the connection performance a burst pressure test specimen, made of an aluminum plate and a glass fiber reinforced PA6 plastic container, was developed. During the feasibility study the influence of interface design and joining process parameter to tightness and burst pressure level was evaluated. The main results will be shown in this paper. Finally, the transfer of the process knowledge to new, compact and easy to recycle hybrid part designs will be discussed. hyJOIN® systems thus offers the possibility for innovative and smart production.