assembly to part.. possible ?

I'm just starting to learn solid works. I have a welded assembly, made of a number of parts. I'm using this part as a learning exercise. I have drawn the assembly's parts individualy, and lined them up in an assembly file. What I need to do is turn the assembly back into a part I can put the finnishing fillets ( weld beads ) on to. I can't see how to turn an assembly into a part... HELP !