Adhesion Strength of Cellulosic Varnish Coated Wood Species as Function of Their Surface Roughness

Table 1

Roughness and adhesion strength test results.

	Roughness value () (µm)				Adhesion strength (N/mm^2)
Species grit size	Tangential		Radial		Tangential		Radial
	80	180	80	180	80	180	80	180
Beech; (0.680 g/cm^3)	35.10; (3.82)^*	29.85; (3.38)	34.39; (4.64)	32.85; (3.44)	2.42; (0.19)	2.36; (0.25)	2.18; (0.23)	2.13; (0.25)
Alder; (0.520 g/cm^3)	37.66; (5.62)	33.69; (3.40)	35.81; (3.66)	30.81; (4.83)	2.15; (0.28)	1.92; (0.12)	2.01; (0.18)	1.96; (0.29)
Spruce; (0.420 g/cm^3)	36.98; (3.98)	32.10; (8.61)	35.13; (4.33)	26.05; (3.03)	2.06; (0.40)	1.92; (0.25)	2.00; (0.22)	1.93; (0.16)
Fir; (0.680 g/cm^3)	37.00; (4.39)	27.53; (6.68)	36.68; (4.42)	24.03; (3.69)	2.06; (0.32)	1.91; (0.29)	1.89; (0.15)	1.86; (0.18)

Values in parentheses are standard deviations.