My turn for a real tough question! I have a KWC s/s under mount sink with granite counter tops, originally installed 7 years ago. About 2-3 years ago, I had to address this issue - the sink coming loose, so when you rinse out the sink .. it drops down into the sink cabinet.
I had a granite fabricator that came out (paid him $250), cleaned the surfaces and reattached it. We once again had to wait 24hrs before my husband reconnected the sink.
Here we are 2yrs later.. the SAME thing is happening. *sigh* I certainly don't want to go through forking out $2-300 for the same thing .. to only have the same thing happen again. Besides, wondering now if my husband can do it (better?!?). Thanks in advance...
They do not use screws, They use brass inserts. These are tiny pipe shaped fittings that have bolt threads on the inside and a rough surface on the out. The fabricator drills holes that are ever so slightly larger then these fittings. Then using a two part epoxy they glue these fittings into the granite top. Once that is done, they then using small threaded bolts fasten the top into place. Normally they also use the epoxy around the top flange of the sink being installed so it has even more holding power and prevents water from leaking out around the area between the sink and the bottom of the stone top. They also use small bolts that are epoxied to the bottom surface of the stone and then use clips to hold the sink into place. These are perfect for doing a repair while the brass insert type is normally drilled out at the fabricators place to prevent drilling through the surface of the stone.