You should cut the bathroom sink drain for a vessel sink down to the exact size before gluing the entire drain assembly together. There are certain preparations necessary before cutting the pipe to size. Follow the simple steps below for the proper cutting techniques for your vessel sink drain.
Step 1 - Popup or Grid Drain?
A popup drain has a stopper that allows the vessel sink to be filled with water during hand or face washing. However, there is a risk the water will overflow from the vessel sink if the water is not checked. A grid drain allows the water to run directly to the drain every time the faucet is turned on.
Step 2 - S-Trap or a P-Trap?
If the drain goes directly to a drain pipe in the floor, you must install an s-trap. If the water should be directed to a drain pipe on the wall, it will need a p-trap.
Step 3 - Determine the Length of the Extension Pipe
The popup or grid drain needs to be connected to the p-trap or s-trap. To do this, cut an extension pipe and glue it to both the physical drain and the trap. Use a female trap adapter to connect the popup or grid drain to the pipe. Use a coupler to extend the trap in case the drain pipe is further away from the wall.
To determine the length of the extension pipe, dry fit the coupler, the drain, and the trap. Now the only space left runs from the drain to the trap. This is where the extension pipe will be connected. Install the female trap adapter to the end of the extension pipe. Insert the female trap adapter to the drain, and visually inspect where the pipe meets the joint in the s-trap or p-trap. Mark that area with chalk or a crayon. Make sure the entire circumference of the pipe is marked squarely.
Step 4 - Cut the Pipe
Place the marked pipe into a miter box. Be sure the pipe is held securely before cutting it with a fine-tooth hacksaw. Carefully cut the pipe making sure the cut is square or it will not be able to fit inside the trap. Remove the burrs using a sharp knife and sand the rough edges afterwards. Clean the pipe with a solvent cleaner as well to ensure a good glossy finish.
Step 5 - Dry Fit and Install the Drain
Dry fit all the components of the drain to check if everything fits correctly. Use pipe cement or glue on all connections, and install every component correctly. Follow the manufacturer’s instructions when using the glue or cement. Wait for the adhesive to dry before using the vessel sink.