Posted by David Sherman on Thursday, May 04, 2006 at 12:19PM :
In Reply to: Re: Brazing, with oxidizing flame posted by Spence on Wednesday, May 03, 2006 at 11:24PM :
An oxidizing flame burns the zinc in the brazing rods. If there's smoke coming up, it's too oxidizing. Neutral is correct. I usually add extra flux, since the flux coating on the rods isn't enough for most repairs. Old cast iron especially absorbs oil and it can be hard to get it clean enough to really suck the brazing in thoroughly. I have an old can of brazing flux that's probably a lifetime supply for me. I don't know what's in it, but it's much better than plain borax which is what some people recommend.
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