A new microwave single-mode applicator was designed,modelled and developed, operating at the ISM frequencyof 2.45 GHz . Using a microwave power of300W, it was possible to melt in a crucible 30-50g of metalmicrospheres, made of commercial Cu and belonging to theP-CuZn20 alloy (P-OT80 brass). The complete melting ofthe load took place in times variable from 30 to 120 s, dependingon the load mass, without preliminary heating.The visual analysis of some of the obtained samples evidencesthe still existing experimental uncertainties, leading tooverheating or non complete melting of the load. The microstructure in the proximity of the surfacein contact with the crucible presented some evidencesof chemical interaction between the melt and the crucible itself,made of SiC.