Manufacture

The initial steps of PSL manufacture as shown in Figure 1 below are similar to those used in the manufacture of plywood. Logs are turned on a lathe to create veneer and the veneer sheets are oven dried.

The veneer sheets are clipped into long narrow strands of wood up to 2.4m (8′) in length and about 13mm (1/2″) in width. Major strength reducing defects are removed from the sheets.

The strands are coated completely with an exterior-type adhesive (phenol-formaldehyde), laid-up with the strands oriented to the length of the member, and formed into a continuous billet which is fed into a belt press. Under pressure and microwave generated heat, the glue is cured to produce a finished continuous billet 280 x 406mm (11″ x 16″) in cross-section.

The billet is cross cut to desired lengths, rip sawn to produce rough stock dimensions or custom sizes, and sanded down to finish dimensions. Larger dimensions are produced by edge gluing billets together using techniques common to those used for the manufacture of glulam.

 Figure 1: Manufacture of Parallel Strand Lumber

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