Got a cast iron exhaust manifold to repair, and after careful cleaning and veeing out, tried TIG brazing using phospher bronze rod.
Only tried it on a small part of the area needing repair, but it seems like a suitable way of repairing the rest...............However I may well be very wrong in thinking this, and wonder if anyone else has any thoughts on TIG brazing cast iron?
TIA
Bronze welding cast iron used to be fairly common back in the days when oxyfuel welding was common.
I am curious. How did you keep from melting the base metal and still get adequate heating to melt the filler using a TIG torch?
Phosporus bronze alloys are not recommended for use on steels or cast irons. The phoshorus does something to the iron and can make it brittle.
The phosphorous combines with the iron to form iron phosphide. Better to use something like BRCuZn-B (manganese bronze) or BRCuZn-D (nickel bronze).
Ok.............................but if filler rod was more suitable, would a repair carried out this way be acceptable?
Yes. I prefer to TIG cast iron using pure nickel rod, but bronze can work fine.
Many thanks will give it a try and let you know how I get on!
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