Preservative Moisture-Repellent Treatments for Wooden Packing Boxes

In a test of the effectiveness of dip treatment of wooden packing boxes, 3,000 M22 small arms ammunition shipping boxes, made primarily from eastern white pine, but including some aspen, yellow-poplar spruce, balsam, and hard pine, were dip-treated in a large number of fungicides, solvents, or water repellents, and exposed in Madison, Wisconsin or Panama, Central America. In supplementary tests, 48 M22 boxes made from southern pine sapwood were dip-treated in several fungicides or fungicide-water repellent combinations and exposed in Gulfport, Mississippi. While the results of these tests were quite complex due to the large number of variables employed, the following general observations can be made: Under the storage conditions encountered, 3-minute dips would be satisfactory for about 5 years’ exposure in the wetter parts of the United States, and 3 years under tropical jungle exposure. For longer exposure, pressure treatments might well be considered. If untreated boxes were stored on treated strips on poisoned soil no treatment would be needed if a watertight tarpaulin or other cover were provided. With fully exposed, dip-treated boxes, the rate of deterioration can be reduced by painting the boxes after treatment. For either dip or pressure treatment, only fabricated boxes or shooks should be treated. Wire-bound crates of rotary-cut southern hardwood veneer decay so fast that it is desirable to treat them if outdoor storage beyond a few months in southern United States is contemplated. High absorptions in veneer boxes, as well as in lumber boxes made of fungus-infected lumber, can be deleterious. Even with light solvents and normal handling procedures, sufficient oil can remain in the wood to harm box contents. Serious dissolving of asphalt in lining materials, with resultant damage to ammunition, has been observed in actual use. The tests leave a number of questions unanswered. Chief among these is the problem of metal corrosion by some of the standard water-borne preservatives. Some corrosion can be attributed to the direct contact of strapping with the treating solutions, but in the waterlogged wood of many of the test boxes, active and serious corrosion began some months after treatment. Also, water-borne pressure treatments of higher retentions should be tried under tropical conditions. For other types of crates and boxes it will be necessary to determine whether a 3-minute dip will afford a much protection to 8/4 and thicker lumber as it does to 4/4 lumber. Plywood containers were not tested, and it can only be surmised that they would react similarly to lumber boxes, and certainly only if water-resistant glues were used.

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