Wettability of sanded and non-sanded transverse and tangential sections of
22 southern hardwoods species was judged by measurement of contact angles u
sing phenol formaldehyde resins. As expected, contact angle values on trans
verse sections were higher than those on tangential sections for both sande
d and non-sanded surfaces. On sanded surfaces, hackberry had the highest me
an contact angle (64.7 degrees), and black oak had the lowest mean contact
angle (50.1 degrees). On non-sanded surfaces, winged elm had the highest me
an contact angle (59.1 degrees), and sweetgum had the lowest mean contact a
ngle (45.9 degrees). In addition, 4 of the 22 species (southern red oak, sw
eetgum, white oak, and post oak) were selected to investigate the effect of
oven-drying, air-drying, and free-drying on wettability. The mean transver
se contact was 2.1 degrees -29.0 degrees and 5.1 degrees -31.5 degrees high
er than radial and tangential values, respectively. The contact angle patte
rn typically displayed for a given species and plane was generally oven-dry
> air-dry > freeze-dry. The species pattern for most methods and planes wa
s: sweetgum > white oak > post oak > southern red oak. White oak and post o
ak gave similar contact angle values.