The interest in 3D metal printing technologies has increased dramatically during the last decades since they enable great weight saving potential for structural components and a significant reduction of material waste during production. Some 3D metal parts offer performance levels that far surpass those of traditional machining methods. Many applications for 3D printing of metal parts are in critical industries such as aerospace, nuclear, defense and medical. Among the existing technologies, Selective Laser Melting (SLM) is well suited to creating low-volume, geometrically complex objects that are difficult to fabricate by other means. When a functional metal component is needed in the shortest possible time, SLM can fabricate it directly from the CAD draft, without any lengthy delay for toolmaking. Studies of topology optimized lightweight structures in titanium show up to 40% weight. With the introduction of high strength aluminium alloys even greater weight saving is possible. The present study is focused on the validation of a recently introduced High-Velocity Oxy/Air Fuel technique for the building up and surface repair of scrap or worn SLM parts produced out of Al alloys. Thanks to the use of air-oxygen mixtures and a carefully designed gas gun by Tecnalia, the HVOAF system can operate within a wide range of flame temperatures while keeping a supersonic flow of combustion products. To limit the creation of a heat-affected zone, that typically results from conventional high-temperature thermal spray processes, the processing conditions have been carefully optimized to work within a cold parameter. A section of a demonstrator was produced by SLM, machined and repaired on the flat face by HVOAF spraying. The quality of the repaired volume was characterized in terms of the microstructure, oxygen content, homogeneity and mechanical properties of the repaired sample. Collected results show a good perspective of this technology for MRO operations.