Welding thread. Iron knee.

I just bought a Mig-100 for $50. I hope it works well. o: It looks pretty clean, and I'm not using it to weld anything that is supposed to support any kind of weight or torque. I bought it simply to fill-in some holes and shave my engine bay (shut up Bert ). For holes that are small, for example the ones atop the radiator support, is it better to just fill them in with the welding wire, or should I still use some sort of plug? I'm looking forward to this and plan to practice a lot before making a mess of my civic. o:

Thanks for the hazing in advance :af:

o: