Preliminary boards were first manufactured to help identify the minimum amount of face furnish that would provide a smooth surface for the particleboard and simultaneously ensure fiber mats were located as practical as possible at the points of maximum stresses. Trial boards manufactured with less than 35% face furnish had dry and flaky face layers. Failure in these boards during internal bond tests were predominantly in the upper and lower particle face layers. Sanding to remove approximately 1 mm of material from both faces resulted in boards with higher bond strength that failed
in the core or fiber layer. As a result material mass for the face furnish was doubled (to ensure greater compaction between particles), the press cycle maintained for a target density of 620 kg/m3
and afterwards approximately 2 mm material sanded off both face layers.