ArtMetal

So I got a new torch and I want to try my hand at brazing (I have only MIG welded everything). I have an old ornamental piece from the top of a chimney that I have displayed in my living room. During the removal it broke in several places. I would like to try brazing to put it back together. I thought I could do this just on the back. How do I have to clean it? Do I need to grind any rust or just brush it and clean with something.What kind of brazing rod do I use? Any helpful tips would be very helpful.

SORRY, this is a repeat entry.