To provide an assembly which is as small as possible which contains a well-protected component and effectively dissipates heat, and to provide a device and a method for use in the rapid manufacture of such an assembly, an assembly includes a component and a housing from which the component is partially separated by narrow casting gaps filled with a casting compound containing a relatively large amount of filler. For the manufacture of such an assembly, a device is used for filling with casting compound and which includes a mounting for securing the assembly in a position which permits air to escape from the casting gaps, which have an external connection during filling. Also there are supply containers and supply lines for the casting compound which open into the casting gaps, and an apparatus for generating pressure. A method which is used to fill narrow casting gaps with casting compound by using such a device. The method involves introducing a casting compound of predetermined viscosity under pressure through the supply lines into the casting gaps, from which the air is displaced.