How to Permanently Seal a Cast Iron Sink for a Water Feature Pond

Plug Strainer Available

• 1

  Clean the area around the cast-iron sink's center drain. Remove all debris and residue from the drain's plug strainer so that it can fit snugly into the drain and plug the drain. Allow the areas that will be sealed to air dry thoroughly

• 2

  Remove the plug strainer from the drain. Squeeze a small ribbon of aquarium silicone into the drain face where the plug strainer normally would sit.

• 3

  Place the plug strainer into the drain to make a snug seal.

• 4

  Squeeze silicone atop the plug strainer to fill the entire depression at the sink's bottom. Stop when the depression is level with the sink's basin.

• 5

  Wet your hands with water, and smooth or smear the silicone with your fingers to level it in the sink.

• 6

  Wait at least 24 hours for the silicone to cure before relocating the sink and/or filling it with water.

Drain Plug Missing

• 7

  Lift the cast-iron sink onto its side so you can access the underside of the basin's drain hole.

• 8

  Cut a scrap piece of cardboard to a size that is slightly larger than the diameter of the drain hole. A utility knife or heavy-duty scissors can be used to cut cardboard.

• 9

  Wrap the cardboard piece in plastic wrap so that one side of cardboard is perfectly smooth with plastic wrap.

• 10

  Tape the plastic wrap's edges to the back of the cardboard. Wrapping tape, masking tape or duct tape may be used.

• 11

  Place the smooth side of the plastic wrap-covered cardboard against the drainage hole on the sink's underside. Situate the cardboard so it is centered over the hole. Use several pieces of duct tape to secure the cardboard in place.

• 12

  Tip the sink over carefully and slowly until the cardboard and drain hole lie snug and flat against the ground and the sink is upright.

• 13

  Squeeze aquarium silicone on top of the drain hole and over the cardboard to a depth of 1 to 3 inches. Extend the silicone 2 to 3 inches beyond the drain hole's edges.

• 14

  Wet your fingers, and use them to mold or smear the silicone to smooth it flush with the sink's surface. A thick, broad layer of silicone layer to cover the drain hole works best.

• 15

  Wait at least 24 hours for the silicone to cure before moving the sink and/or filling it with water. Keep the cardboard piece tape on the sink's bottom to acts as a protective buffer against the ground once the sink is positioned in a garden.