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What are concretor’s nippers and pliers coated with?

Shop for Concrete Nippers and Pliers

There are three surface finishes found on concretor's nippers and pliers. The surface finishes applied to concretor’s nippers and pliers are nickel or chrome plating, polishing and black phosphate.

What is black phosphate?

Concretor's pliers with a black phosphate coating applied. Black phosphate, also known as parerization and atramentising, is a surface finish applied to many steel and iron tools. It’s a chemical process that removes a very small layer of material from the surface of the tool and replaces it with zinc or manganese dioxide.

Why is black phosphate used?

Sprue cutters are coated with black oxide to help prevent them from corroding. Tools are coated with a black phosphate for two reasons: as a form of corrosion protection for the steel when it’s sealed with oil, and to eliminate glare, so reducing eye strain.

How is black phosphate applied?

Concretor's nippers being rinsed and cleaned in a bath of titanium salts. First, the tool surface is cleaned and rinsed in a bath containing titanium salts. This helps to activate the surface of the metal before it goes into the phosphating bath.
Concretor's nippers getting a black appearance from the phosphoric acid bath containing zinc salts. The tool is then placed in a phosphoric acid bath in which zinc or manganese salts have been dissolved. This results in a reaction depositing manganese or zinc phosphate on the tool.
Wonkee Donkee says: "It’s the depositing of phosphate that gives the tool a black appearance."
Rinsing the acid from concretor's nippers. The tool is then removed from the acid bath and rinsed before being dried. This phosphate coating does not offer corrosion protection in itself as it is porous, so oils or other sealants are used to fill the porous holes in the phosphate layer and provide the tool with the required corrosion protection.

Why are some concretor’s nippers and pliers jaws polished?

Oil is used on concretor's nippers and pliers to prevent the metal from rusting. Many surface finishes applied to tools for corrosion protection can wear off under intensive use, leaving them vulnerable to rust if exposed to water or left in a moist or damp atmosphere. The easiest way to prevent this is to carry out some basic maintenance and regularly apply a coating of oil (see  Concretor’s nippers and pliers maintenance and care).
Polished surface on the jaws of concretor's nippers and pliers. Oil works best as a corrosion protection when applied to smooth surfaces so for this reason the jaws of many concretor’s nippers and pliers are polished smooth. It will often only be the jaws that are polished as this is the part of the tool that experiences wear during use.

What is nickel plating?

Nickel plating Nickel plating is a thin layer of nickel deposited on a workpiece, which can aid with wear resistance, corrosion protection and give a shiny appearance

How are tools nickel plated?

Electro-plating Once the shape has been formed, steel concretor’s nippers and pliers are sometimes coated with a layer of nickel for corrosion prevention, using an electro-plating process.
Nickel plating uses an anode, cathode and a DC electrical current to deposit a layer of nickel on the tool. The tool is submerged in a solution called an electrolyte that contains metal ions. An anode made of nickel is connected to a positive electrical terminal and also placed in the electrolyte, while the concretor’s nippers or pliers are connected to a negative terminal to form what’s known as the cathode.
Nickel plated concretor's nippers and pliers DC (direct current) is applied through the anode and cathode. This causes the metal of the anode to dissolve ions into the electrolyte, which are then deposited on the cathode (concretor’s nippers or pliers).

What is chrome plating?

Chrome plating is a less expensive form of corrosion protection. Chrome plating is a form of corrosion protection used on many tools. It is available in two forms: standard (shiny) and matt, sometimes called satin. Chrome plating provides a better level of corrosion protection than black phosphate and is less expensive to apply.

How is chrome plating applied?

Degreaser is used to remove the chemicals that were used to clean the surface of the parts. The first stages in the chrome plating process are cleaning processes that buff the surface of the parts, followed by chemical cleaning with acid that removes surface blemishes. After this, the parts are rinsed with a degreaser and dried to remove any remaining acid.
Chromium trioxide and sulphuric acid are used to apply the chrome plating. The parts are now ready to be placed in a chrome bath which contains chromium trioxide (CrO3) and sulphuric acid (H2SO4), and have an electrical current passed through them. By altering the ratio of chromium trioxide to sulphuric acid, the temperature and the amount of electrical current passed through the solution, it is possible to alter the finish of the chrome plating on the part.
Parts are rinsed and spun dry. The parts are then rinsed to remove any remaining chromium trioxide and sulphuric acid, before being placed in a centrifuge and spun to dry them.

Which coating should you choose for concretor’s nippers and pliers?

It's really your choice as to what is the best surface finish or coating to have on your concretor's nippers and pliers. This is not an easy question to answer as it will depend on what wire or nails you will be cutting and how much maintenance you are willing to carry out. While chrome and nickel plated concretor’s nippers may offer the best form of corrosion protection, these types of coating can become chipped, which will remove part of the protection.
It's really your choice as to what is the best surface finish or coating to have on your concretor's nippers and pliers. Black phosphate cannot be chipped off, but as the jaws of concretor’s nippers and pliers with a black phosphate surface finish are usually polished they will require more maintenance to prevent them from corroding. Polished jaws also have less wear resistance than chrome or nickel plated ones and so may require sharpening more often (see Concretor’s nippers and pliers maintenance and care).