When making repairs that are being glued, it is critical to get all the old glue off and get fresh material exposed. If you do that, then hysol should hold. But, it is a slow cure. Got to get used to having something else to work on while it cures.

I have never seen the hysol itself crack. From what I have seen, usually if a hysol joint fails, it is because the bond to the material failed, probably because of poor surface prep, at least in my case.