How to Install an Undermount Sink That Fell Off the Countertop (Marble/Granite)

in this instructable I'll show you how to Re-Glue an Undermount Kitchen Sink that fell off the Countertop
The following method works on Granite and Marble Kitchen Sinks & Countertops,

1. Granit Glue
2. a piece of lumber
3. A Scraper
4. Sand paper
5. And a Bar clamp, also known as an F Clamp

use the scraper to remove the glue from the rim of the sink, if the glue is too stiff then heat it up with a hot air blower and then scrape it off.

once you remove it, use the sand paper to smoothen the surface of the rim.

and also scrape off the glue from the base of the countertop.

before you mix the Glue do the following:

• Wipe the to be glued surfaces with a damp cloth to remove the dust from them
• Remove the jaw from the Bar Clamp
• Put the Piece of lumber across the opening of the sink

Now mix the Glue with the hardener according to the written instructions and make sure to mix them well.

apply the glue on the rim of the sink (applying the glue shouldn't take more than 3-4 minutes)

Now you will need a second person to help you install the sink,
while the second person holds the sink beneath the countertop, insert the bar clamp through the drain hole of the sink, and the insert the jaw in the bar clamp and tighten it on the piece of lumber.

Leave it for 12-24 hours so that the glue fully cure, the curing time depends on the type of the used glue.

after 12-24 hours, remove the clamp and then attach the drain hose, and now the sink can be used normally.

for more details check out this video: