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 effect iveness of the original wood treatment, but most fabricators dislike the oi ly nature of the chemicals available for treating this damage. The ability of selected alternative water- and oilborne preservatives to protect simula ted bolt holes was explored in a laboratory trial using Douglas-fir heartwo od, red oak, yellow-poplar, and loblolly pine. The test methodology produce d poor results with water-based chemicals because of the severe leaching tr eatment used, but was a reasonable predictor of the field performance of oi l-based materials. Copper-8-quinolinolate (Cu-8) appeared to be the best oi lborne material evaluated, whereas boron provided protection when leaching was not severe.