Red brass and bronze are usually resistant to pool corrosion. And while aluminum is effective in pool areas, it is not effective in the water itself. Nickel-aluminum bronze is excellent for saltwater pools. And silver, gold, and platinum are very durable materials to use in swimming pools.
Brass is a term used to describe any of several metallic compounds that contain significant amounts of copper and zinc. There are two main types of brass: hard brass and soft brass. Hard brass is harder and more brittle than soft brass. It is used primarily for plumbing fixtures such as faucets and toilets. Soft brass is less hard and more malleable than hard brass. It is used primarily for decorative purposes such as door knobs and lamp bases.
When you hear people say they're using "brass" in their pool, what they mean is probably gold or silver. Gold is the most popular material used for swimming pool accessories because it is easy to work with and highly visible when polished. But other metals can be used instead. Silver is less common but still available for purchase at many pool stores. It is known for its bright color and durability.
Alloys containing some percentage of brass have been used for centuries by sailors as materials that are tough, wear well in use, and do not corrode even in salty water.
Very strong acid is the only easily accessible substance that may corrode stainless steel. Stainless is generally unaffected by alkali, so if your pool shop claims that staining is caused by high alkalinity, they are mistaken. In any event, the worst-case "alkalinity" in a typical pool is quite low. About 150 ppm (parts per million) of calcium or less.
Stainless steel will always contain some amount of iron, which will react with acid to form a rusty color. However, this does not mean that it will break down completely. Rather, it means that more acidic substances will cause it to stain. For example, if you were to pour lemon juice into your pool and let it sit overnight, the stainless would turn yellow because of the acidity of the lemon juice.
If you were to then add more lemon juice to the pool, the stained area would re-stain the metal underneath. This is because acid reacts with the iron in the stainless and removes it from its original structure. There is no way to prevent this reaction entirely, but you can minimize its effect by adding more acid or alkaline substances to neutralize the pool.
Overall, stainless steel will not decay in your pool. However, it will stain if exposed to acid for long periods of time. This does not mean that it will dissolve, but rather that it will change color.
Surprisingly, even metals with excellent corrosion resistance will fail if exposed to salt for an extended length of time. You may assume that well-known corrosion-resistant metals like copper, bronze, and brass might pull it off, but when dipped in salt solution, they, too, will corrode. The reason is simple: Both copper and brass are alkaline metals which means that they have a tendency to lose electrons. This makes them vulnerable to corrosion when in contact with acids or other substances that can drain their charge.
When you pour salt into a bag of pretzels or potato chips, it's not only to flavor them, but also to protect the metal cans inside from corrosion. If left untreated, aluminum cans would be almost as susceptible to corrosion as iron or steel.
Even though salt doesn't cause brass to corrode, it does allow other things to eat away at it over time. Brass objects such as doorknobs, faucets, and bathroom fixtures can become tarnished due to exposure to the environment. This is called "salting out" and it happens when small particles of metal that have come off your appliance get trapped in the salt crystals and prevent any more from forming. Over time, this can lead to patches of discoloration on your sink or bathtub.
If you want to keep brass looking new, wash it with soap and water after being exposed to salt or salty foods.
Brass alloys containing more than 15% zinc, such as Admiralty, aluminum brass, Muntz metal, navy brass, and manganese bronze, are prone to a kind of corrosion in seawater known as dezincification (or parting corrosion). This is because water has the ability to remove zinc atoms from the surface of the alloy. As these atoms dissolve into the water column, they are replaced by hydrogen ions from water molecules, thus leaving a porous layer of zinc hydroxide on the surface of the material.
This problem can be avoided by using stainless steel for marine applications or by adding other elements to the brass composition that inhibit this type of corrosion. For example, copper added to the brass will inhibit dezincification because copper has the same effect on water molecules as zinc does; that is, it removes hydrogen ions from between water molecules so they can join together to form hydrogen bonds.
Another solution is to use an algaecolumn filter system. These filters consist of layers of cellulose materials through which water passes until it reaches a thin plastic membrane at the bottom. Salt particles cannot pass through the membrane and stay with the cellulose material, which then needs to be changed regularly. Using this method will help prevent brass from corroding due to exposure to saltwater.
Finally, you can coat the brass with a protective paint.
When the zinc, copper, and tin components of a brass alloy are exposed to water, the brass corrodes. Exposure to mercury and ammonia, in addition to water, can induce brass corrosion. Corrosion causes the metal to lose weight and often changes its color. Brass that has corroded can be treated with a bronze restorer to replace some or all of the metal that has worn away.
What is the best way to preserve brass? Brasso, a mixture of 40 percent hydrocarbon oil and 60 percent nitric acid, is the most effective means of preserving brass. Other methods include coating the brass with shellac or using waxes as protective agents. Do not use petroleum products such as gasoline or diesel fuel as they will cause the brass to burn.
Why should brass not be immersed in liquid nitrogen? Immersing brass in liquid nitrogen freezes the water within the brass and prevents it from evaporating, which would cause the brass to crack. While this process is useful for preserving pieces that would otherwise be discarded, it is important to avoid directly immersing very thin brass because heat from inside the piece will cause the piece to melt if frozen in liquid nitrogen.
How does heat affect brass? As brass heats up it begins to expand; if it is not allowed to do so freely this expansion can cause the piece to break.