Featured The Gearbox is Cracked, please help

Soldering will not work, it is not meant to make a strong bond. Just like JB weld it does not modify the workpiece surfaces as it is just epoxy that contains steel particles. You need to make a weld in order to make a bond comparable in strength to the original material.

 

You would have to do a pretty darn neat welding job to work. I imagine things would get caught on the bead.

 

Yep agreed it will be difficult, probably not worth the effort unless the gearbox is a one-off

Brazing is more like soldering than welding, there is similarly no modification of the substrate. It is a lot stronger than soldering, but if the gearbox cracked because its original homogeneous alloy strength wasn't strong enough then a braze isn't going to fix it.

 

Don't think so, brazing fill has a lower melting point than the material being brazed and as such will not be stronger. The crack will be on the weakest point already, so it needs to improve the strength of the original alloy for it to be a useful fix.

 

these days the gearbox shell more cheaper, I rather buy another cheap new ( or up to CNC one ) than try to fix them.