Mould and stain became troublesome problems on lumber manufactured at a coastal British Columbia sawmill, and the difficulties were suspected to be a fault of the mill's antisapstain treatment. Forintek technical staff visited the sawmill and planer mill and used two procedures to gather assessment. Firstly, boards were pulled from spray box chains after spray treatment and one-inch square samples were punched from four faces of these boards for chemical analysis of DDAC, one of the active ingredients in the formulation being used. With a large number of samples, this procedure quantitatively assessed DDAC retention levels at points along boards. Secondly, fluorescent dye was added to the spray solutions and special paper strips were stapled along the length of boards prior to treatment in the spray box. The paper strips were then retrieved for examination under ultraviolet light. This procedure is largely a qualitative one, showing the pattern of spray coverage over the whole board. Liquid samples of the treatment solutions were taken from both the sawmill and planer cross chain day tanks to determine their DDAC concentrations.
Methods for the analysis of boron in wood were reviewed and one, a method in which base titration of a mannitol/boron complex is done, was chosen for possible routine use. Method parameters were tested and the stages were modified to arrive at a routine which can determine boron content in wood within 5% accuracy. Hot water leaching of chip samples, 2.54 x 2.54 cm x 2 to 3 mm thick, of wood which has been given borate/antisapstain treatment is better than 95% efficient within four hours; this is as efficient as a ten-cycle extraction on a soxhlet apparatus. Using an automatic titrator, analysis for boron is done by titrating a mannitol complex of the boron in the extract. The simplicity, low expense, speed, and accuracy of this routine give it the advantage over several other methods. The aqueous extracts of wood, the mannitol reagent, and secondary components of boron treating formulations can all add to the apparent boron content of the wood sample; these factors are variable but generally total about 8 *g boric acid equivalent per cm2 of wood surface. The method is also suitable for the analysis of boron in heavily (preservative) treated wood.
Research to commercialize ultra-low-volume charged-drop spray application technology for the fungicidal protection of unseasoned lumber during transit and storage is described. Tests were made to establish the feasiblity of using the Electrodyn spray in a commercial setting and a field test investigated the efficacy of treatments and chemicals applied.
Preservatives - Tests
Spraying
Preservation - Non pressure processes - Brushing and spraying
