Suitability of different sealer media for moisture uptake tests of wood

Partial sealing of surfaces of test specimens is essential for determining direction-dependent water absorption of wood. Preliminary tests with existing sealants showed limited applicability particularly for standardisation. The objective was to find new sealer material. The suitability of four different materials (bitumen, polyurethane acrylic resin, liquid rubber spray, aluminium tape) was investigated. Their sorption capacity and water vapor tightness were determined with an automated sorption balance. The experiments revealed that most of the used sealers were not diffusion-tight or showed outgassing. Only the aluminum tape seems to be suitable.