Advice on welding radiator water pipe

[srgore67]

I am planning to weld the hole closed on a Mitsubishi radiator water pipe. You can't find these pipes very easily and this is a pipe I'm adapting to fit my 1990 eclipse. I cut the smaller side pipe off and it has this gold looking finish where the manufacture welded it. I'm thinking it's silicon bronze? The pipe is metal so I'm not sure why they didn't weld it with metal filler. I would like to mig a steel circular metal patch on it which is bigger than the current hole and almost covers up the gold filler that was used. My question is can I just weld it with steel mig filler wire or do I have to use some special wire/rod ?




Thanks in advance!!