The transportation industry is faced with a demand to reduce fuel consumption and consequently the emission of CO2. One way to achieve this is to reduce the weight of the vehicle. Aerospace, automotive and railway industries using aluminium alloys for their products require new joining methods fulfilling their specific technological demands. As not all of the aluminium alloys can be successfully joined by conventional fusion welding alternative methods are needed. Friction Stir Welding (FSW) technology, which takes place at temperatures below the melting point offers a cost effective alternative to conventional joining methods and has already proved itself in the industry. There are two main types of FSW tools: conventional single-side tools and self-reacting ones, otherwise known as bobbin tools. In most cases, the single-sided FSW requires special, heavy machines. The use of self-reacting units such as a bobbin-tool can reduce the system requirements. Another advantage of the bobbin tool technology over the single-sided FSW is the feasible application in tubular structures and hollow profiles, widely used in the above-mentioned industries. One of the broadly deployed aerospace aluminium alloys - 2024 in the case of an aircraft is mechanically fastened as welding by any means is not recommended for this alloy because of the degradation of corrosion resistance that occurs as a result of weld heat. Single-sided FSW technique has been already proved to produce very good quality welds in alloy 2024 in different conditions. Bobbin tool FSW of 2024 is a further development of that attractive joining technique. The GKSS bobbin tool is designed as a portable flexible unit that can be handled by industrial robots. Bobbin tools currently used are operated by heavy gantry systems and focus mainly on thick sections, over 8 mm. The GKSS bobbin tool as light, portable unit is able to perform welds in thin sections, 4 mm and less. Performed tests indicated that the measured side and traversing forces while bobbin tool welding were similar as in singlesided FSW, which indicates the possibility of producing the welds directly with the aid of a robot. The research programme carried out involved the following fields of interest: development of the GKSS bobbin tool (pin and shoulders et al.) and welding system as well as development of the bobbin tool technology with highlighted welding of 2024. Two pin geometries have been selected and welds for testing and characterization purpose have been produced. The properties of produced welds in 2024 have been evaluated on the microstructure, hardness, tensile and bending tests results. Satisfactory weld quality has been achieved with tested sets of parameters and pin tool shapes. Performed heat generation and heat transfer analysis indicated that the heat power dissipated in bobbin tool welds is not significantly higher but in addition with extremely low heat losses has an enormous influence on the properties of a weld.weiterlesen