Soldered guard durability?

[PURPLEDC]

Is that because 450-500° F is unlikely to reach the edge above 350°, or just that a brief heat above a previous 350-400° temper isn't going to change it?

From what I have seen when soldering a guard you heat the guard and it acts as a heat sink. The blade still gets hot but as long as a color shift isnt happening it should not be an issue.

 

[RX-79G]

From what I have seen when soldering a guard you heat the guard and it acts as a heat sink. The blade still gets hot but as long as a color shift isnt happening it should not be an issue.

With brazing and soldering you generally need both pieces of metal to exceed the solder's melting point for it to stick. But that doesn't mean the full heat propagates to the edge.