The silicone prevents water from creeping under the edge of the kitchen sink. As it dries and cracks over time, you need to replace it regularly to keep the area dry and clean.
Steps
Step 1. Make sure the edge of the sink is clean and dry
Step 2. Remove any old silicone residue with a cutter
Step 3. Cut the old silicone along the entire length and lift it off the sink
Step 4. Clean the area with kitchen paper soaked in denatured alcohol to remove all traces of the old silicone, and to be sure to work on a clean surface where the new sealant will adhere
Step 5. Wait until the edge of the sink is completely dry
Step 6. Apply masking tape to the kitchen counter all around the sink, leaving enough space to put the silicone
This will make it easier to clean and you will be sure to make a well-defined and even line.
Step 7. Cut the tip of the silicone tube with the cutter
Step 8. Make sure that the hole is as big as the thickness of the rim of the sink you need to fill, otherwise you will get too much silicone in one go
Step 9. Insert the silicone tube into the special gun and push the piston towards the bottom of the tube
Step 10. Prepare the tube by pulling the trigger a couple of times, until you see some silicone coming out of the tip
Step 11. Rest the tip against the edge of the sink, where it connects to the kitchen counter
Step 12. Slowly pull the trigger to release a thin line of silicone
Step 13. Move the gun while squeezing the silicone, keeping the tip always attached to the edge for a deep application
Step 14. Apply silicone all around the perimeter of the sink
Step 15. Remove the tape from the shelf
Step 16. Wet your index finger with water and smooth the sealant against the edge of the sink and kitchen counter
This creates a watertight sealed closure. Press the silicone firmly and slide your finger around the entire perimeter.