It works because it can stretch. When wood bends, it has to stretch on the outside of the curve, which gets longer. Wood can't stretch, so steam benders use a steel backing strap on the outside of the curve to force compression to the inside of the bend (the inside gets shorter, but the outside stays the same length). With Cold-Bend™ Hardwood, the wood is compressed before it is bent. Therefore it can stretch on the outside of the curve during bending. This also allows for much more extreme wood bends to be made. Since the wood is first plasticized in an autoclave and then compressed in a hydraulic press, greater stretch can occur in bending than a steam bender could achieve through compression with a backing strap.
The two before and after electron micrographs above, illustrate how the straight cell walls develop a corrugation to them, or a bellows effect. It is a lot like the difference between a straight plastic drinking straw, and a flexible drinking straw. The straight straw resists bending. The flexible straw has a bellows that allows for extreme bending because it can stretch out when it bends. The corrugation is not noticeable at the macroscopic level. However, sometimes figure in the wood is enhanced from compression, if it was in there to begin with, especially fiddleback figure.
