This work was carried out to improve the mechanical properties of weld metals deposited by nickel oxidizing electrodes, together with additions of copper and molybdenum, through the grain refinement or by solid solution hardening. The oxidizing electrodes are characterized by the lower levels of diffusible hydrogen and, hence, by the lesser possibility of cold crack formation when compared to rutile electrodes. However, the weld metal deposited with this type of electrode shows mechanical properties below that obtained by rutile electrodes, as long as important alloy elements, such as Mn and Si, are lost by oxidation. In order to avoid this situation and obtain weld metals with better mechanical properties it was added alloy elements that are not significantly affected by the oxidant character of the coating, such as Cu and Mo. Two test specimens were prepared for welding, where spaced holes and a notch were machined in each one for the addition of both elements, Cu and Mo. Different percentages of these elements were measured by Energy Dispersive Spectroscopy microanalysis. From these results it was performed microstructural analysis using optical microscopy, grain size measurements and microhardness tests to evaluate the influence of each element in the weld metal and compare them to each other. The results showed that molybdenum has a stronger influence on the microhardness of the weld metal than copper. Regarding the grain size it was noted an opposite influence of the elements, where the addition of Mo caused a decrease of the grain size and the addition of Cu caused a slightly increase, until the grain size becomes constant.