New materials are constantly being developed for additive manufacturing. Therefore, they are ideally trialled and tested in small quantities first. Particularly in the development of pastes from bio-based residues, the rapid adaptation of the material with regard to process parameters is of crucial importance. Based on a low-cost, commercially available material extruder for plastics (MEX-TRB/P), an extruder for processing pastes is being developed with the aim of minimising the work steps involved in installing the material container and keeping assembly, disassembly and cleaning as simple as possible. All the components required for the extruder can either be manufactured with MEX-TRB/P or are available as easily accessible purchased parts. The required STL files for the components and a list of other purchased components for the extruder will be made available as open source via the SAMSax platform, among others. The extruder is controlled via Klipper on Repetier Server.