Good spread or adhesive in some areas, poor in others.
| CAUSE |
SOLUTION |
| Insufficient or Non-Uniform Pressure/Non-Uniform Stock Thickness
| Do not use stock when dimensions vary. |
| Press must deliver recommended pressure in order for surfaces to be brought into intimate contact. |
| Adjust planers to avoid excessive planer marks. Typically, 16 to 32 marks per inch are recommended. |
| Non-Uniform Spread of Adhesive
| Recover and/or regroove worn spreader rolls. |
| Replace worn bearings on spreader rolls if needed. |
| Spreader rolls must be parallel with each other and with doctor rolls. |
| Keep spreader rolls clean of dried adhesive. |
| Be sure top and bottom rolls apply an equal spread of adhesive. |
| Fast operation of spreader may cause foaming of adhesive. |
| Do not use stock when dimensions vary. |
| Avoid twisted and defective core stock. |
| Adjust planers to avoid excessive planer marks. Typically, 16 to 32 marks per inch are recommended. |
| Avoid excessive kerf marks or heavy/deep kerf marks on edge of lumber. |
| Assembly Time Too Long For Certain Conditions
| Shorten assembly times. |
| Increase spread rate. |
| Twisted and warped stock stacks loosely, allowing adhesive to precure. |
| Cold Core or Face Stock
| Avoid using stock below 60°F (16°C) temperature. |
| Consider using infrared lamps or hot air during pressing. |
| Unclean Stock
| Be sure all stock is free of any foreign matter. |
| Poor Face Sheet Surface Penetration
| Avoid using case-hardened lumber. (Light sanding may assist penetration). |
| Lack of Intimate Contact Throughout Load
| Use properly prepared lumber |
| Use sufficient pressure for adequate squeeze-out and for intimate contact of panels. |
| Stacks should be of equal height under platens. |
| Poor Alignment of Press Load
| Be sure press platens are not out of line causing uneven pressure. |
