Old timber preparation process - involves first roughening surface of the piece of timber and dampening it till humidity in surface layer is at least 30 per cent.

: Michanickl, A.; Boehme, C.

Abstract
The preparation process involves separating a surface layer from the core of a piece of timber, leaving this core to be used for another purpose. The surface of the piece of timber is first mechanically roughened. The piece of timber is then placed in water or in an aqueous solution until the humidity of the wood in the surface layer is at least 30 per cent. It is then steamed with steam at a temperature of 120-160 degrees Celsius. This loosens the surface layer, which in the next stage can be detached from the piece of timber. The wood may be dampened with a high pressure water jet. ADVANTAGE - This is a simpler way of detaching surface layer without damaging the core.