Metal fasteners such as Heavy Hex Bolts, Heavy Hex Screws, Headcote Screws and Stainless Cap Screws are the types of Building Fasteners that most people are familiar with but there is a place for nonmetallic fasteners as well. They make up less than 1% of the fasteners that are produced but they do have certain properties than cannot be reproduced by metallic materials.
Nonmetallic fasteners are made from various types of plastics. Some of the reasons that one might choose to use fasteners made of plastic is that they are lightweight but one of the biggest reasons is that they are resistant to corrosion. They also have superior electrical insulating and thermal properties. For those who need a fastener that can meet appearance demands or be matched for identification processes, plastic fasteners are a good choice.
Types of Plastics
There are many types of plastics that fasteners can be made from and they all have their strengths and weaknesses. Nylon 6/6 is the most used plastic for making fasteners though. It has good strength properties, especially the ability to be torqued. It also has good resistance to fatigue and creep and it is tough. After it has been deformed it has good resiliency to rebound back to the original shape, which gives it great elasticity. One of the most like features of nylon 6/6 is its resistance to corrosion from chemical solvents and the ability to self-extinguish if it is set on fire. There are some disadvantages to nylon 6/6, though. In hot and sunny environments it tends to embrittle and dimensional stability is can be affected because it has relatively high moisture absorption.
There are many other types of plastics that are used for different reasons. If you need a plastic fastener with superior dielectric properties you could use one made of polystyrene, but keep in mind that it tends to be brittle and may crack if impacted. High density polyethylene might be a better choice because the dielectric properties are similar or sometimes better and it is also inexpensive but it only has a medium strength. If you want something that has better shock loading poly carbonate fasteners are good and tend to have acceptable dielectric properties, while being emotionally stable, but they do tend to deteriorate if they are exposed to direct sunlight. Other plastic fasteners that you could explore include fluorocarbons, fasteners that are made from fluoroethylene (TFE), acrylic fasteners, acetals, and flexible or rigid vinyls.
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.