1 Splits and/or open joints on the ends of panels.
Possible causes: 1) high moisture content; 2) dry conditions in the plant; 3) snipes in the staves; or 4) the sized staves have been inventoried longer than 24 hours prior to being laminated.
Corresponding recommendations: 1) Keep wood at 6-8 percent moisture content; 2) keep the plant at 30 percent minimum relative humidity, use an end sealer; 3) inspect the equipment being used for joint preparation and look for faulty hold-downs; or 4) reduce gluing inventories to allow pressing to take place within 24 hours.
2 A wood failure only over part of the surface.
This is caused by uneven pressure due to the following possible causes: 1) pressure only to the top or bottom; 2) improper clamp spacing; 3) machining; or 4) uneven glue application.
Corresponding recommendations: 1) Apply pressure to the top and bottom; 2) apply pressure near the ends and 8-12 inches or 20-40 cm apart; 3) make sure surfaces are flat and square; and 4) ensure the adhesive coverage is even over the entire surface.
3 You have an under-cured joint/the glue line is still wet.
Possible causes: 1) low plate current setting; 2) short cure cycle; 3) little or no pressure; or 4) high moisture content.
Corresponding recommendations: 1) Increase the power to the required level or install a vacuum capacitator if at the maximum; 2) increase the cycle time; 3) check the filler boards for the correct gauge pressure; or 4) check that the wood’s moisture content is within the recommended 6-8 percent and if it is above 8 percent, re-dry the wood.
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