Biocide protection of field-drilled bolt holes in red oak, yellow-poplar, loblolly pine, and Douglas-fir

Field-drilling of holes in treated wood products sharply reduces the effectiveness of the original wood treatment, but most fabricators dislike the oily nature of the chemicals available for treating this damage. The ability of selected alternative water- and oilborne preservatives to protect simulated bolt holes was explored in a laboratory trial using Douglas-fir heartwood, red oak, yellow-poplar, and loblolly pine. The test methodology produced poor results with water-based chemicals because of the severe leaching treatment used, but was a reasonable predictor of the field performance of oil-based materials. Copper-8-quinolinolate (Cu-8) appeared to be the best oilborne material evaluated, whereas boron provided protection when leaching was not severe