Breaking in

Hi i just bought my son a Kala Ka-c how long will it take for the mahogany wood to "break in"???

None at all. The KA-C is made of laminate wood, which is constructed by gluing multiple layers of wood together. The concept of "playing in" or "opening up" really only applies to solid wood. It probably sounds the way its always going to sound.

With that being said, is there anything about the uke that's unsatisfactory? It may be a result of setup, and quite easy to correct.

The KA-C is a laminate so as soon as your strings stop stretching, you are good to go. There shouldn't be a huge tone change over time. Laminates don't "open up" as solid woods are said to.

As Rich and Freeda said, the uke will not open up and improve in sound over time, with a laminate it is what you hear is what you get. But the strings will stretch and the uke will go out of tune frequently with new strings, so it could take a couple of weeks for it to hold its tune.