Is brazing sufficient for this repair?

[junkaddict]

Cracked vise nut. Cast iron. I was just going to braze it. Would there be any advantage to using Ni-Rod instead?

[danlb]

According to the properties sheets, the tensile strength of ni-rod is close to the cast iron itself. Brazing is a bit (30%) weaker. What caused the failure? Bending? Stretching? Compression?

Dan

[junkaddict]

According to the properties sheets, the tensile strength of ni-rod is close to the cast iron itself. Brazing is a bit (30%) weaker. What caused the failure? Bending? Stretching? Compression?

Dan

It broke in the direction the screw pulls, so it would be a stress fracture in sheer I believe.

[Illinoyance]

Braze is weaker than the cast iron. Arc welding with nickel, or any other metal, leaves a hard, brittle zone behind the weld. The ideal process would be oxy-acetylene welding using cast iron rod and borax flux.

[BigMike782]

Brazing will provide more than enough strength and will be less problematic than welding.

[914Wilhelm]

If you braze it you can probably add a little “extra meat” in the form of brazing to more than make up for the decreased strength.

[rjs44032]

If you decide to braze, remember that CI absorbs oil like crazy. You may be surprised by the amount that sweats out. When silver brazing CI, I always flux and sweat out the oil at least twice before applying the braze. Hope this helps.

Best Regards,
Bob

[RWL]

Is there anybody else that thinks the irregularity of the crack and crumbling edges looks like it occurred in "punky" metal. In other words, it looks like there may have been a weak spot in the metal itself. If that's the case, braze may be stronger than what was there originally.

[Mike K.]

No I think you just found the hinge point for the applied stress. I concur brazing would be sufficient. Keith Rucker just did a video where he brazed a good sized chunk of cast iron to an existing member check it out here: https://www.youtube.com/watch?v=KIj5ij84qlU

[Dedave]

So how did it turn out?