Sorry for the delay, I finally got the corner repaired. I was surprised at how easy it was and how STRONG that rock hard water putty actually is. To test it, I tipped the whole cabinet with one and back and forth by the repaired corner and it is SOLID.
Thanks to IG-88 for his detailed help, followed his instructions and now that corner is SMOOTH.
Mixed enough putty for all holes, chips, and broken corner.

Cleaned off broken area with air can....ttssssssssss

Filled the area with putty, it was not pretty and a bit messy.

Spread more putty all over the broken piece


I didnt have a C-clamp but this did the trick (took some re-adjusting) but did the job.

I did get a C-clamp later (not pictured, hands got dirty)...because I wanted to make sure it was EXTREMELY tight.

LUNCH TIME.......DOUBLE BACON CHEESE BURGER (homemade)

RESULTS:
So strong, again I can tilt the whole cabinet with one hand holding on to the broken corner. Its sanded with a 100 grit, you cant even feel any difference at all. I am very happy with the results.
