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

Table 3

Duncan test results of the samples.

Strength properties	Factors	LS; mean	Homogenous; groups^*
Surface roughness	Wood species
	Beech	33.053	b
	Alder	34.498	a
	Spruce	32.571	bc
	Fir	31.313	c
	Grain orientation
	Tangential	33.744	a
	Radial	31.974	b
	Grit size
	80	36.099	a
	180	29.620	b
Adhesion strength	Species
	Beech	2.277	a
	Alder	2.012	b
	Spruce	1.981	b
	Fir	1.936	b
	Grain orientation
	Tangential	2.105	a
	Radial	1.999	b
	Grit size
	80	2.100	a
	180	2.004	b

Different letters indicate statistically significant difference between the groups.