As early as 1700 B.C., the ancient inhabitants of Crete utilized a terra cotta plumbing system with faucets of marble, gold and silver. Lead-pipe systems and personal bathrooms existed during the Roman period (1000 B.C.-476 A.D.). Rome’s public baths utilized silver faucets, and by the fourth century A.D., Rome had 11 public and 856 private baths.
Although much has improved in the past two millennia, it wasn’t until the last century that faucets took on some of the characteristics we now enjoy. The first adaptation – the single-handled mixer faucet – began with Al Moen in 1937. After the requisite trial and error, the first one was sold to a plumbing supply company in 1947. Today, these faucets are used in over 40% of American homes. The ball valve was another mid-20th-century invention, which was introduced in the first Delta faucet in 1954.
The most widely used material for faucets is brass – an alloy of copper and zinc. It is used because of its resistance to soft-water corrosion and hard-water calcification. Faucet manufacturers utilize brass bar stock, which has been melted, cast and rolled to 0.13-2 inches in diameter. The manufacturing process for faucets has become very automated, and the process can be quite complex. For larger machined faucets, over 32 machining operations using a rotary machining center are required.
Alternatively, some faucets are hot forged to a near-net shape, saving time and waste. For this process, the metal is heated to the temperature at which it is soft and malleable enough to be formed into the necessary shape. The temperature is around 900˚F, which is very near the melting temperature. Precision machines then form the faucet by means of die forging, which is typically done in a single step. After the forging operation, the parts are trimmed and pierced if necessary. The scale layer is then removed by blasting with brass chips. Only minor machining is required to meet the final dimensions.
After machining, the faucets move to the finishing operation. Because it is cost-effective and corrosion-resistant, chrome plating is typically used. Before the brass can be chrome plated, however, it is first electroplated with nickel. A thin layer of electroplated chro-mium is then applied.
More unique finishes can be applied using the physical vapor deposition (PVD) process, which applies a metal coating in a vacuum chamber. This chamber is comprised of a vacuum pump; a tank that emits several types of gases; a corrosion-resistant (zirconium) target rod, which is the metal source; and racks for holding the faucet parts. An electric arc heats the target to vaporize the material. The gases are chosen such that one provides the color and one the corrosion resistance. The target material combines with these gases and adheres to the faucet, creating a virtually indestructible bond.
Technology, necessity, economy and ecology have resulted in the development of faucets and faucet components that are manu-factured from a variety of materials, all of which utilize high-temperature techniques in their manufacture. Delta uses a valve with a diamond coating to add life to the faucet. The diamond valve lasts up to 5 million uses and keeps water inside the faucet out of con-tact with potential metal contaminants. Other technology, driven by the desire to save money by minimizing hot water usage or gov-ernmental regulations requiring maximum flow rates, uses less water while providing the same high-flow result with 50% less water.
Some applications, such as faucets for beer, use stainless steel as the material. The stainless lever is more durable than brass for heavy-use applications. One manufacturer is also adding an antibacterial agent to the stainless followed by a proprietary heat-treatment process. The faucet not only maintains the stainless benefits, it is also resistant to E-coli and staphylococcus aureus.
Now you know some of the many ways high-temperature thermal processing makes the faucets we use every day and helps make them better. IH