In most industries that are involved in manufacturing, it is often necessary to fasten the goods produced using fasteners such as the carriage bolt. One of the mistakes that many people make when using such bolts is not ordering them in the right specifications. It is important that one always tries to get all the […]

In most industries that are involved in manufacturing, it is often necessary to fasten the goods produced using fasteners such as the carriage bolt. One of the mistakes that many people make when using such bolts is not ordering them in the right specifications. It is important that one always tries to get all the details right when making such orders. This is because at the end of the day, the quality of the fastening will determine the quality of the end product. In most cases, it will also determine how long it lasts as well.


One of the variables that need to be gotten right when ordering carriage bolts and other fasteners is the type of coating to get them in. There are different coatings that can be used for different applications. It is therefore important to always try and match the type of coating to the reason you are getting the fasteners in the first place. If you are interested in protecting the fasteners from corrosion, some of the common coatings you can use for this include:

  • Zinc Plating

This is one of the cheapest and commonest fastener finishes. As you can imagine, it simply involves putting a thin coat of zinc on the fastener either through the use of electroplating or simple painting. The end result is a silver fastener that is normally resistant to corrosion and which is also aesthetically pleasing as well. To make the coating harder, the coating can also be treated with chrome through a process known as chemical chromate passivation.

  • Phosphate coating

This is a rarer method of coating fasteners. One of the disadvantages of this form of coating is that it does not offer as much protection from corrosion as other forms of coating. However, it does provide a very good base on which painting can be done, making it the coating of choice for applications where this might be necessary.

  • Cadmium plating

This is an uncommonly used method of coating fasteners. Plating fasteners with cadmium gives them better resistance to corrosion compared to zinc plating. The end result often resembles zinc plating.

  • Galvanizing

This is a form of zinc plating which involves dipping the fasteners in a bath of molten zinc. Afterwards, they are then centrifuged in order to get rid of any excess zinc to give the fasteners a more polished look. The difference between galvanizing and zinc plating is that in the former, the plating is often a lot thicker than the latter, which gives it more protection against corrosion.
galvanizing
These are just some of the ways in which fasteners can be protected from corrosion. The next time you are out there shopping for fasteners, it would be a good idea for you to try and get ones that have the right type of coating that you need. This not only prolongs the life of the fasteners, but in some cases can also make using them a lot easier. The trick to getting it right is understanding the environment in which the fasteners will be used, and then making sure that the coating used is designed to work in such an environment.

About the Author

Larry Melone
By Larry Melone
President

Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.

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