Gluing ~ this should be carried out within 48 hours of the planing
operation to reduce the risk of the planed surfaces becoming
contaminated or case hardened (for suitable adhesives see page
556). Just before gluing up the laminates they should be checked
for `cupping.' The amount of cupping allowed depends upon the
thickness and width of the laminates and has a range of 0„75 mm
to 1„5 mm.
Laminate Thickness ~ no laminate should be more than 50 mm thick
since seasoning up to this thickness can be carried out
economically and there is less chance of any individual laminate
having excessive cross grain strength.
Straight Members † laminate thickness is determined by the depth
of the member, there must be enough layers to allow the end
joints (i.e. scarf or finger joints † see page 553) to be properly
staggered.
Curved Members † laminate thickness is determined by the radius
to which the laminate is to be bent and the species together with
the quality of the timber being used. Generally the maximum
laminate thickness should be 1/150 of the sharpest curve radius
although with some softwoods 1/100 may be used.
Laminated Timber