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Email: barry@windsorinc.net

Drainage Holes are essential for all fabrications that include hollow or semi hollow sections to permit rapid exhaust of
entrapped pretreatment chemicals. The BEFORE photo shows a rectangular tube with end caps welded at both ends. Windsor was assured it would be impossible for pretreatment chemicals to penetrate the welded ends as the customer preferred not to have visible drain holes on his product. The AFTER photo shows the tube from the same job after pre-treating and painting, where a small amount of chemical penetrated welds and (at 500 degrees Fahrenheit in the cure oven) generated enough hydraulic pressure to swell and deform tube(s). (Note light colored chemical trail on inside of tube.) During the chromium phosphate pretreatment process, aluminum parts are subjected to over an hour of pressure washing in hot chemicals and vapors.