A disposal flange is a device used to suspend a garbage disposal under a sink. Acting as both the disposal mount and the sink drain, a disposal flange is a critical component in a leak-free sink. Commonly held in place by several flange bolts, it is critical that each bolt be tightened evenly to avoid warps and leaks. Plumbers putty is commonly used between the sink and the disposal flange to help seal the opening against leaks.
The typical disposal flange is installed as a unit comprised of the top and bottom flange as well as the flange ring and the mounting bolts. The disposal will produce enormous vibration and torque while switching on and operating, so the installation is very important and all instructions should be followed to the letter. Trial fitting of the disposal flange is recommended to be certain that no surprises conflict with the proper installation of the disposal unit. Since most of the installation is accomplished below the unit, a helper is highly recommended for all flange-related repairs. It is also a wise idea to dry the sink and the sink drain area thoroughly prior to beginning to install a new flange unit.
A piece of plumbers putty or the equivalent is shaped around the drain hole at the bottom of the sink. This is done on the inside of the sink, not the underneath or bottom of the sink. The putty should be sufficiently sized to allow excess putty to be squeezed out of both the top and bottom of the sink, effectively sealing the flange once it is pushed down into the drain hole. It is critical that the disposal flange not be moved once it is seated into the putty or serious leaks could occur. The remainder of the installation of the flange is performed from below the flange and the sink.
To finish the flange installation, the gasket is placed over the bottom of the flange and pushed up against the sink bottom. A clip is commonly used to hold the gasket in place. The flange bottom is placed up against the sink and tightened by the mounting bolts. Each bolt must be tightened equally to avoid leaks, damage to the flange and damage to the sink. The installation of the disposal flange is complete when the bottom flange ring is tightened into position. Some manufacturers recommend allowing the flange to sit overnight prior to completing the disposal installation.