I had someone tell me that my 130 lb. Kohler undermount sink (K-6626-6U-0) is too heavy to install underneath a Quartz countertop. I can't believe this is true. Could someone here tell me?
I hope it wasn't your countertop person who told you this, if it is then it would probally be better to find a different one. the reason I say this is it would show a lack of experience. when ever we install a cast iron undermount we simply put supports inside the sink cabinet to support the weight of the sink. you probally wouldn't want to fasten it to the counter top because if either settling occurs or if the counter top isn't setting firmly on the cabinet at all points it could cause the top to crack. so this is easily avoided by simply placing supports under the sides of the sink. usually on these sinks the cabinet isn't much larger than the sink, so simply by screwing a board to the side of the cabinet so that the top of the sink is even with the top of the cabinet and this would still allow enough room for the sink to be moved so that it will match up with the cut out.
I hope this has been helpful