Photo By Columbia Forest Products
Listed below are some troubleshooting tips and solutions for cold pressing panels.
Total delamination with little or no substrate failure. Probable causes: (1) pre-cure (no glue transfer); (2) low pressure (poor contact); 3) short press time. Solutions: (1) Increase glue spread; (2) Increase pressure; (3) Increase pressure period.
Spotty bonds. Probable causes: (1) uneven surfaces; (2) worn spreader rolls. Solutions: (1) calibrate cores to uniform thickness and/or increase pressure; (2) replace or re-groove rolls.
Glue bleeds through the face veneers. Probable causes: (1) excessive glue spread; (2) excessive pressure; (3) wrong adhesive type. Solutions: (1) Reduce the glue spread; (2) reduce the pressure; (3) consult your supplier.
Telegraphing of core defects or banding. Probable causes: (1) Excessive pressure; (2) uneven or variable thickness; or (3) foreign material on the core. Solutions: (1) Reduce the pressure; (2) re-sand the core; and (3) pre-clean the core.
Warpage of panels. Probable causes: (1) Excessive or unequal adhesive spread; (2) high moisture content; (3) unbalanced construction. Solutions: (1) Reduce the adhesive spread and/or make sure the top and bottom spread are equal; (2) maintain a 6-8 percent moisture content in the material; (3) check the grain orientation and the number of plies.
Brilliant white on glue squeeze-out and/or glue line. Probable cause: (1) chalking caused by low temperature. Solution: (1) Raise the temperature of plant, wood and adhesive above minimum use temperature of adhesive.
Source: Franklin Adhesives & Polymers. For more information call 800-877-4583 or visit FranklinAdhesivesAndPolymers.com.
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