Performance of Tuff Brite C™ and other formulations against blue-stain, mold and brown-stain in freshly-sawn rubberwood (Hevea brasiliensis) in the humid tropics of Peninsular Malaysia
A H H Wong, T L Woods
The relative anti-sapstain and anti-mold efficacies, including brown-stain development in freshly-sawn rubberwood (Hevea brasiliensis) in the Malaysian tropics, between selected water-based product concentrations of formulations Tuff Brite CTM without/with added Borax (at 1.5/0, 1/1.5, 1.5/1.5 and 2%/1.5%), PQ8TM without/with added Borax (at 2.5/0, 1.5/1.5, 2/1.5 and 2.5%/1.5%) and NeXgenTM/NeX-BriteTM combination (at 1/0.25, 1.5/0.25 and 2%/0.25%) were assessed visually. Rubberwood boards, dipped in these concentrations for 1 min. were subjected to an 8 weeks sapstain trial in a FRIM sawmill shed. Sodium pentachlorophenate/Borax combination (at 2/1.5 and 2%/2%) was the reference anti-sapstain chemical. The rough-sawn boards were rated for blue-stain and mold weekly, while both the planed and the internal faces of the boards, sawn lengthwise into two-halves, were rated for blue-and brown-stain only after 8 weeks. Results for the rough-sawn boards, planed boards and the internal faces of the boards revealed a generally consistent excellent performance of Tuff Brite CTM without/with Borax against blue-stain and mold in rubberwood, protection being marginally better than that of NaPCP/Borax. Over a range of concentrations, performance by the remaining fomulations PQ8TM without/with Borax and NeXgenTM/NeX-BriteTM were variable: rated satisfactory (generally <10% surface infected) and/or poor (31-50% of surface infected) against sapstain and/or mold. Against brown-stain development (i.e. to conserve the natural cream/yellow hue in rubberwood), Tuff Brite CTM without/withBorax also appeared to be relatively better (generally yellow-to-light brown hue) than the other formulations, but perhaps only marginally so than NaPCP/Borax (light blue as well as yellow-to-light brown hue observed).