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CLINIC ELECTROCOATNG pfonline.com/experts How Can I Tell If it's Been E-Coated? Cleaning an E-coat Oven Q. I own a car restoration business and buy quite a few after- Q. How can we clean an electrocoat oven market parts. I know that OEMs use e-coat as an anticorrosion treatment protection in their vehicles, but how do I know if the black parts I buy from aftermarket dealers are e-coated or not?—M.H. A. Automotive body and repair shops around the world are supposed to be using replacement parts equivalent to the OEM-manufactured parts, but we know from experience that this is not always the case. Application of electrocoat requires facilities with high capital investment and a high degree of technical expertise to operate, which not all automotive aftermarket suppliers have. Write to the aftermarket part supplier and ask if the parts they supply to you are e-coated or not. If you get no response, then you can do the following: A quick visual gloss evaluation could be the first indication of whether an aftermarket part was e-coated. Parts exhibiting extremely low gloss below 30 or high gloss above 70 probably were not e-coated. For typical automotive electrocoat paints, the application gloss falls between 30 and 70 depending on the technology, e-coat supplier used and the application parameters, including cure temperature, time and p/b ratio. The low and high gloss extremes can be easily detected by a trained human eye. For a more accurate test, the parts can be rubbed with a cloth or cotton tip impregnated with a solvent to see if the coating transfers from the part to the cotton tip or cloth. If after 40-50 rubs back and forth on the same spot you do not see any paint transfer to the cotton tip or cloth, then the chances are greater than 99 percent that the part was painted using e-coat . If you see paint transfer to the cotton tip or cloth, then the aftermarket part likely was painted with an imitation black paint. The rubbing must be vigorous while applying sufficient pressure on the rubbed surface. The solvent must be acetone, methyl ethyl ketone or methyl isobutyl ketone, which are very powerful and can dissolve any paint that is not crosslinked like electrocoat. If a more scientific analysis is required, other expensive analytical techniques can be employed. Gas chromatography, liquid chromatography, mass spectrometry and other thermal and chemical identification techniques can be used to determine the chemical composition of the paint and whether it is electrocoat. Electrocoat is widely accepted in the automotive world because of its corrosion properties and its great chemical resistance to most automotive organic fluids such as gasoline, brake fluid, wiper solution, anti-freeze and organic solvents in general. Electrocoat paint develops this capability because, after application, the paint is cured at high temperatures ranging from 325 to 400°F, which enables the electrocoat epoxy paint to accomplish a high degree of polymerization and crosslinking to form a strong, chemically inert epoxy polymer. 34 DECEMBER 2013 — pfonline.com for producing high-quality parts?—J.X. A. Cleaning an e-coat oven at adequate frequencies is necessary to maintain good operating performance. The climate and geological environment, whether or not you are in a heated/air-conditioned facility or have many open doors and direct exposure to outside conditions, in many cases influence the proper cleaning frequency. In the electrocoat JOSE A. TIRADO / Consultant industry, oven electrocoat@pfonline.com cleaning frequency typically ranges from once per quarter to once per year, but what works for some companies does not necessarily work for others. Local conditions for oven cleaning prevail over all other design or operating conditions or recommendations. To clean an e-coat oven, proper lighting and the availability of compressed air are necessary, as are working tools such as brooms, rags, a vacuum sweeper, etc. A proper oven cleaning must include at least the following four basic steps: 1. Use compressed air to blow off all oven surfaces, including monorails, oven fans, oven structures, and all sheet metal surfaces and corners. 2. Use brooms and a vacuum sweeper to remove all loose debris and dirt. 3. Use wet rags to wipe clean all surfaces, including monorails, fans, structures, sheet metal surfaces and corners. Make sure there is no loose red dust residue (iron oxide) on any walls or surfaces. 4. After steps 1, 2 and 3 are completed, operate the oven fans (circulation and exhaust) at ambient temperature with the burner off for at least 4 hrs so that the oven can perform a final self-cleaning. Never use water to hose down the oven. This can damage the heat insulation in the oven panels and significantly decrease its effectiveness. After completing these steps, the oven will be clean and ready for testing and verification with production parts. Clear E-coat Over Chrome? Q. Can a clear e-coat be applied over a chrome-plated surface (brass or zinc)? I've seen chrome plate listed on some websites as a surface that can be e-coated, but the sites offers no specifics. What type of surface preparation would be needed? What level of adhesion is achievable?—R.C.