Cw-laser weldings at different power, focal position, and welding velocity were performed on hypereutectic spray-compacted aluminum alloys and AlMg3. Two light-conducting cables, 0.1 and 0.4 mm in diameter were used. For AlMg3 shrink pores were observed for a broad range of parameters. However, for a narrow window pore free weldings seem possible. For comparison, the spray-compacted hypereutectic aluminum alloys (AlSi17Fe4Cu2.5MgZr, AlSi20Fe5Ni2, and AlSi35Fe2Ni) were welded in extruded condition. The metallographic microstructure is very different and may support crack free weld seams. The results emphasize the impact of the energy density. Since for aluminum even small amounts of alloying elements change the heat conductivity drastically, all parameters have to be adjusted carefully.