What are hand drills and braces coated with?

29th February 2020


What are hand drills and braces coated with?


	Shop for Hand Drills and Braces


		The frames of hand drills and braces can have any one of several surface finishes or coatings applied, these include: chrome plating, nickel plating, acrylic and enamel paint and black Japanned finish.

		Surface finishes are applied to hand drills and braces to protect them against corrosion.

		Corrosion is a reaction between a metal and the moisture in the atmosphere around it that degrades the metal, reducing its strength. The most common example is rusting.

		Black Japanned finishes
		Black Japanning is a lacquer finish used on metals which contain iron, such as steel. It is made up of bitumen and thinners such as turps or naphtha with varnishes added. It is painted directly onto the bare metal and then cured (baked) at about 200°C.

		Black Japanning got its name from the finish becoming associated with products that had been produced in Japan. It became a popular finish on early car parts due it its durability and relatively quick drying time in comparison with other finishes at the time. It was extensively used in the production of the Ford Model T.

		However by the end of the 1920s, black Japanning was being used far less due to the invention of quick drying lacquers which would dry faster and could be produced in a greater range of colours.

		Paints
		The frame and drive wheel of hand drills are sometimes painted to protect them from corrosion. The most common types of paints used for this are enamel and acrylic paints.

		Enamel paints dry to form a hard shiny finish. They were traditionally oil based paints but there are now water based paints that also describe themselves as enamels as well.

		Acrylic paint is water based but becomes water resistant once dry. Acrylic paint generally dries faster than enamel paints as the water used in it evaporates faster than the oils in enamel paint. Acrylic paint is not as hard as enamel but is more elastic and flexible, which means it is less likely to crack.

		Paint vs. black Japanning
		Black Japanning was originally used as it dried quicker and lasted longer than the paints of the time. However, modern paints will dry faster and offer corrosion protection for a similar length of time.

		It is easier to touch up or repaint a painted hand drill as paint does not require baking and is readily available.

		Nickel or chrome plating
		Nickel and chrome plating is when a material (usually steel) is coated with a layer of nickel (in the case of nickel plating) or chrome (in the case of chrome plating). This can be done for several reasons, such as corrosion protection, wear resistance and appearance.

		How is nickel plating done? Electroplating Nickel plating is most commonly carried out by a process called electroplating, sometimes referred to as electrochemical plating. This is done by placing the workpiece to be plated in an electrolyte solution where it is then referred to as the cathode along with a nickel bar which is then referred to as the anode.

		A direct current is applied to the anode and the cathode, causing the anode to be positively charged and the cathode to be negatively charged. Nickel ions in the electrolyte are attracted to the cathode and deposited on the surface of the workpiece. These ions in the electrolyte are replaced by ions from the nickel anode, causing the nickel anode to dissolve in the electrolyte.

		Electroless plating Electroless plating does not require the use of electrical current. Instead, the workpiece is placed in an aqueous solution containing nickel ions, and a reducing agent (usually sodium hypophosphite) is added to the solution.

		The workpiece surface acts as a catalyst for the reaction, causing nickel ions in the solution to be deposited on the workpiece. The aqueous solution containing the nickel ions may be heated to around 90°C in order to speed up the reaction.

		What are the advantages and disadvantages of each plating process? Electroless plating produces a much more even and consistent layer of nickel than electroplating, particularly in recesses and holes and on workpiece edges. Electroless plating does not require the workpiece to be connected to a current, so, many small workpieces can be plated easily at the same time, in the aqueous solution.

		Electroplating however is often a cheaper way of plating material, and so is more commonly found on hand drills and braces.

		How is chrome plating applied? The first stage in the chrome plating process is an abrasive cleaning process that blasts either small steel particles or aluminium oxide powder at the surface of the metal tool. This buffs the surface of the tool, which will later help the chrome plating solution adhere to the metal’s surface.

		The next stage is another cleaning process. This time, the tool is placed in a bath containing acid. This removes any blemishes that may remain on the surface of the tool. After this, the tool is rinsed and dried to remove any remaining acid.

		The tool is now ready to be placed in the chrome bath which contains chromium trioxide (CrO₃) and sulphuric acid (SO₄), and has an electrical current passed through it. By altering the ratio of chromium trioxide to sulphuric acid, the temperature and the amount of electrical current passed though the solution, it is possible to alter the finish of the chrome plating on the tool from a standard finish to a matt one.

		The tool is then rinsed with water to remove any remaining chromium trioxide and sulphuric acid before being dried off.

		Which is better nickel or chrome plating?
		This will depend on the thickness of the plating that is applied, as thicker plating will provide better protection. Chrome plating is more durable than nickel and adds more of a lustre and shine to a finished part. However, the added shine can show up scratches in the surface of chrome plating more than with nickel plating.