  A study with synchrotron radiation X-ray tomographic microscopy (SRXTM) of
PUR, PVAC, and UF adhesive bond lines in beech wood, bonded under various
growth ring angles is presented. After determining the hardening
characteristics of the adhesives, we evaluate the bond line morphologies, and
the adhesive penetration into the wood structure. We find distinct bond line
imperfections for the different adhesive systems. To describe the adhesive
distribution inside the bond line we propose the saturation of the pore space
instead of the commonly used maximum penetration depth. The results are the
basis for a penetration model of hardening fluids into hardwood (part II).
