In plumbing, a sink or basin is a bowl-shaped fixture that is used for washing hands or small objects such as food, dishes, nylons, socks or underwear. In American plumbing parlance, a bathroom sink is known as a lavatory.
Sinks generally have taps (faucets) that supply hot and cold water and may include a spray feature to be used for faster rinsing. They also include a drain to remove used water; this drain may itself include a strainer and/or shut-off device and an overflow-prevention device. Sinks may also have an integrated soap dispenser.
When a sink becomes stopped-up or clogged, a person will often resort to use of chemical drain cleaner or a plunger, though most professional plumbers will attack the clog with a drain auger (often called a "plumber's snake").
Sinks are made of many different materials. These include:
- Stainless steel
- Enamel over steel or cast iron
Stainless steel is commonly used in kitchens and commercial applications because it represents a good trade-off between cost, usability, durability, and ease of cleaning. Most stainless steel sinks are made by drawing a sheet of stainless steel over a die. Some very deep sinks are fabricated by welding. Stainless steel sinks will not be damaged by hot or cold objects and resist damage from impacts. One disadvantage of stainless steel is that, being made of thin metal, they tend to be noisier than most other sink materials, although better sinks apply a heavy coating of vibration-damping material to the underside of the sink.
Enamel over cast iron is a popular material for kitchen and bathroom sinks. Heavy and durable, these sinks can also be manufactured in a very wide range of shapes and colors. Like stainless steel, they are very resistant to hot or cold objects, but they can be damaged by sharp impacts and once the glass surface is breached, the underlying cast iron will often corrode, spalling off more of the glass. Aggressive cleaning will dull the surface, leading to more dirt accumulation. Enamel over steel is a similar-appearing but far less rugged and less costly alternative.
Solid ceramic sinks have many of the same characteristics as enamel over cast iron, but without the risk of surface damage leading to corrosion.
Plastic sinks come in several basic forms:
- Inexpensive sinks are simply injection-molded thermoplastics. These are often deep, free-standing sinks used in laundry rooms. Subject to damage by hot or sharp objects, the principal virtue of these sinks is their low cost.
- High-end acrylic drop-in (lowered into the countertop) and undermount (attached from the bottom) sinks are becoming more popular, although they tend to be easily damaged by hard objects - like scouring a cast iron frying pan in the sink.
- Plastic sinks may also be made from the same materials used to form "solid surface" countertops. These sinks are durable, attractive, and can often be molded with an integrated countertop or joined to a separate countertop in a seamless fashion, leading to no sink-to-countertop joint or a very smooth sink-to-countertop joint that can not trap dirt or germs. These sinks are subject to damage by hot objects but damaged areas can sometimes be sanded-down to expose undamaged material.
Soapstone sinks were once common, but today tend to be used only in very-high-end applications or applications that must resist caustic chemicals that would damage more-conventional sinks.
Glass, concrete, and terrazzo sinks are usually designed for their aesthetic appeal and can be obtained in a wide variety of unusual shapes and colors such as floral shapes. Concrete and terrazzo are occasionally also used in very-heavy-duty applications such as janitorial sinks.
Styles of sink
Self-rimming (top-mount) sinks sit in appropriately-shaped holes roughly cut in the countertop (or substrate material) using a jigsaw or other cutter appropriate to the material at hand and are suspended by their rim. The rim then inherently forms a fairly close seal with the top surface of the countertop, especially when the sink is clamped into the hole from below.
Bottom-mount or under-mount sinks are installed below the countertop surface. The edge of the countertop material is exposed at the hole created for the sink (and so must be a carefully finished edge rather than a rough cut). The sink is then clamped to the bottom of the material from below. Especially for bottom-mount sinks, silicone-based sealants are usually used to assure a waterproof joint between the sink and the countertop material. The advantage of an "under-mount" sink is that it gives a contemporary look to the kitchen but the disadvantages are extra cost in both the sink and the counter top. Also, no matter how carefully the cut out is made, the result is either a small ledge or overhang at the interface with the sink. This can create an environment for catching dirt and allowing germs to grow.
Solid-surface plastic materials allow sinks to be made of the same plastic material as the countertop. These sinks can then easily be glued to the underside of the countertop material and the joint sanded flat, creating the usual invisible joint and completely eliminating any dirt-catching seam between the sink and the countertop. In a similar fashion, for stainless steel, a sink may be welded into the countertop; the joint is then ground to create a finished, concealed appearance.
How Ceramic Basins Are Made
Pottery is made by a blend of clays, fillers and fluxes being fused together during the firing process. A white or coloured glaze is applied and is fused chemically and physically to the clay body during the same firing process. The finished product (vitreous china) has a very hard surface and is resistant to fading, staining, burning, scratching and acid attack. Due to the firing process and natural clays used, it is normal for the product to vary in size and shape, and +/- 5mm is normal.
An automatic sink is a sink fitted in a public restroom. It uses a motion-sensing valve to detect the user's hands moving beneath the faucet. It then turns the water on.
Sinks, especially those made of stainless steel, can be fitted with an integrated drainboard, allowing for the draining of washed dishes, such as the sink in the photograph at the start of the article.
- Domestic water system
- Floor plan
- Garbage disposal
- Plumbing fixture (drains)
- Proverbial kitchen sink
- Tap (valve) (faucet)
- Trap (plumbing)