Re: Brass radiator what type solder and flux? With the advent of aluminum and plastic radiators I fear this is an additional dying art/talent. Steel Pipe Flux Cored Wire – This special wire will allow mechanics to weld steels without the need to use excess materials like flux mainly because https://automotiveparts05094.blogsmine.com/27732956/a-review-of-types-of-solder-to-use-on-aluminum-radiator