Global Fastener News

November 28, 1994 FIN — Manufacturers are doing more coating of fasteners because of environmental requirements and for cosmetic reasons, Michael J. Basinsky of Sun Belt Coating Inc. told the fall meeting of Southeastern Fastener Association.
Environmental regulations concerning plating of fasteners have narrowed the cost differential, making coated fasteners a viable alternative with the added advantage of superior corrosion resistance, said Basinsky, the production manager for Tulsa, Oklahoma-based coating company.

As the technology improves, coated fasteners are gaining advantages over stainless steel and other corrosion resistant materials, Basinsky said.

Advantages he cited include: Coated fasteners offer low cost alternatives; allow increased pre-loads for improved fatigue resistance and reduced loosening under vibratory loading; prevention of galvanic corrosion; and hazardous waste disposal minimization of heavy metals when non-plated, thus subject to less regulatory interference. Coatings are also utilized on stainless fasteners to reduce galling, he added.

“Major changes in the composition of the coatings from solvent to water borne, will have significant impact on the performance of coated fasteners,” Basinsky said. “Coating manufacturers have come under pressure to reduce Volatile Organic Compound (VOC) emissions more prominent in solvent-based systems.”

The trend is the same in the painting industry: “You use water-based latex house paint instead of the oil-based 20 years ago,” Basinsky, pointed out.

The newer coatings are not yet perfected, Basinsky acknowledged. “Progress is slow, but the pressure to do it will take us there.”
The majority of current systems remain solvent based, he noted.

High-performance coatings are typically heat cured to enhance the chemical conversion process of the polymers making the coated fasteners more corrosion resistant, Basinsky said.

Typical applications can be found throughout the automotive and boating industries and in power equipment.
High-performance coatings are available in virtually unlimited colors to meet the growing demands of customers seeking color-matched or coding applications.

Among his customers wanting color-matched fasteners are aluminum building and air-conditioning manufacturers.
Problems associated with coated fasteners include sticking of smaller parts when bulk processed or labor-intensive handling of certain types of fasteners requiring multiple coats.

Typical of bulk-processed coated fasteners will be thin non-uniform appearance for a single coat. A dual coat system will provide uniform color but have visible “nesting” marks. After three coats, Basinsky termed the nesting marks “insignificant.”

In corrosion applications, performance is measured through a laboratory testing apparatus that uses the presence of “red rust” as an indicator. “Unfortunately the results provide only a relative basis of comparison that is not directly correlated to real-life applications,” Basinsky said. “In other words, ‘Your mileage may vary’.”
Basinsky said the most important consideration when ordering coated fasteners is end-user specifications-which are critical to determining customer needs and provåiding protection for both supplier and applicator.  ©1994/2011 Fastener Industry News

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