FT Archives

Liquid Q&A

Sunlight's Effect on Electrocoated Parts

I have heard that over time, primer will begin to break down if left unpainted. Will electrocoat also break down over time if it isn't painted over relatively quickly?

In industrial markets, epoxy coatings (liquid, powder and electrocoat) often are used outside because of their corrosion resistance. If the coated parts will be inside or covered, the epoxy will not break down. But if you leave an epoxy-coated part in the sun for a long period of time, the sun's ultraviolet (UV) rays will begin to break down the epoxy finish whether it is liquid, powder or electrocoat. The ability of the coating to break down is not due to the coating technology but to the intrinsic chemistry of corrosion-resistant epoxies.

There are a few solutions to keep the part from degrading. First, a UV-durable topcoat (liquid, powder or electrocoat) can be applied to the epoxy primer. This topcoat keeps the sun from penetrating the epoxy finish, leaving the coating intact. Second, an epoxy electrocoat primer with added UV durability has been developed, but is somewhat higher in cost. This product may be a good fit for epoxy-coated products that are left outside for short periods of time. Finally, acrylic electrocoat is available for parts that are exposed to sunlight for long periods of time. It will provide a high quality finish with good UV durability and some corrosion resistance.

Clear Electrocoat Technology

I am currently using a clear lacquer to coat plated parts. I am having difficulty getting the spray into recessed areas on the parts, leading to part failure in the field. I know electrocoat technology is ideal for covering recessed parts. Is a clear electrocoat available?

Clear coats, both anodic and cathodic, can indeed be applied by electrocoat. Clear electrocoat is an electrodeposited clear coating process designed to add value to plated parts by increasing chemical resistance, perspiration resistance, wear resistance, corrosion resistance, and extending the overall lifetime of the finish. Clear electrocoat is applied on metals (electroplated or polished surfaces) to protect the metals from corroding or changing color. Dyes and other additives are used to control color, translucence and gloss. Thus, it can be widely applied in situations to enhance appearance while adding special protection. Often, the clear electrocoat formula can be enhanced for added performance with a desired property such as hardness. This alternative to spray and dip lacquers produces a hard, uniform, drip-free coating capable of conforming to any geometry. Total uniform coverage is achieved even in recessed areas, resulting in exceptional performance. Current markets utilizing this technology include jewelry, hardware, plumbing fixtures, lighting and anodized aluminum.

Bulk Electrocoat

My company coats very small parts, which we rack individually. I have heard of bulk electrocoating. How does this process work?

Typically, small parts are hung on a rack and processed through an electrocoat system. Unfortunately, racking very small parts can be labor intensive and costly. The bulk application of electrocoat can produce a significant volume of parts and reduce the overall application costs. There are three processes utilized to electrocoat parts in bulk: basket, barrel and belt line. The barrel and basket processes are better suited to fasteners, whereas the belt line is suitable for coating small parts. With the new advances in electrocoat chemistry, these processes deliver uniform coating finishes with minimal touch marks and virtually no part-to-part sticking.