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POWDER COATING, February 2018 35 Here are some questions for you: • Are you sure your current process yields a water-break-free part as it exits the last process stage? • Have you checked your parts for water-break-free surfaces after the dry-off stage? • A r e y o u c o n f i d e n t t h a t y o u a r e achieving full cure on the parts? • Where is the delamination? Is it uni- formly poor, or is it on the sanded or abraded areas? With this information, I can narrow down a probable cause and pinpoint areas to attack first. Other issues that may affect product adhesion include line stops, part drying, contaminated rinse, poor-condition final rinse, or too much dissolved solids. Transfer, or lag time, is- sues between pretreatment and dry off can be related, as well as excessive dry-off temperature. I hope this gets you on the right track. Please feel free to contact me with additional information. PC Editor's note For further reading, see articles under the Surface preparation head- ing in the "Index to Articles and Authors 1990-2017" Reference and Buyer's Resource Issue, Powder Coating, vol. 28, no. 6 (December 2017), or search the Article Index at www.pcoating.com. All articles listed in the archive are available for free download to registered users. designed for multi-metal lines. When you're using a cleaner phosphate, it's imperative that the formula incorporate a fluoride source. Fluoride is critically important to help in deoxidizing or mi- croetching the aluminum substrate. You indicated that the pH of your bath is from 5.5 to 5.7. This tells me that it probably doesn't have a fluoride source. Usually, these materials run somewhere between 3.75 and 4.50 in pH. Please check with your chemical providers to see what upgrades they can make to be more aggressive on the aluminum. The three nonnegotiable standards for nonferrous preparation are as follows: 1. Remove all organics, casting release agents, waxes, and any processing oil from the parts. 2. Provide deoxidation or etch to the aluminum. This can be accom- plished chemically or mechanically. 3. Provide a high-quality final rinse. Deionized or reverse osmosis is preferred.