Recycling of plastics becomes increasingly important for a sustainable use of resources. Polyamide is suitable for recycling because of its good mechanical values and its chemical resistance against many organic solvents. Cast polyamides have a high molecular weight compared to polyamides, which were synthesized through polycondensation. Despite chain degradation, they are particularly well suited for finite processing a second time. The molecular weight of cast polyamide is sufficient for processing through injection molding. However, for other processing methods like thermoforming the molecular weight has been considered too low. A low molecular weight results in a low melt strength and a low melt viscosity. Molecular weight increasing additives were added to cast polyamide wastes and extruded in a twin-screw extruder to enable further processing through thermoforming. A linear chain extender as well as a polymer backbone was used. Rheological investigations in a plate-plate-rheometer showed a notable increase in shear viscosity. Furthermore, in a thermal characterization it could be shown that the temperature processing window for thermoforming will not be influenced by the additives. In first experiments, foils were successfully extruded and formed to components.