| Walmark Corporation phone: (847)546-0400 fax: (847)546-1777 |
| Glue Line Appearance |
| Symptom | Cause | Remedy |
| Glossy Appearance | Insufficient pressure. | Increase pressure. |
| Prolonged open time. | Reduce open time. |
| Adhesive On One Surface Only | Poor joint fit. | Improve joint quality. |
| Prolonged open time. | Reduce open time. | |
| Precure of adhesive. | Check wood moisture content or decrease assmembly time. | |
| Inadequate pressure. | Increase Pressure. |
| Spongy Looks Cellular | Foam in adhesive. | Replace glue. |
| Inadequate pressure. | Increase pressure. | |
| Pressure removed too soon. | Increase press time. | |
| Chalky | Adhesive, Stock and Surroundings Too Cold. | Warm up plant (65oF) and Stock. |
| Blue-Black Stain On Hardwoods | Iron contamination. | Check equipment for contact of adhesive bare iron. |
| Thick, Noticeable Glue Line | Poor fit. | Check joint quality. Avoid hollow joints. |
| Inadequate pressure. | Increase pressure. | |
| Prolonged closed assembly line. | Reduce assembly time. |
| Finished Construction Appearance |
| Symptom | Cause | Remedy |
| Prominent Glue Line viewed in incident light. |
Thick glue line. | Improve joint quality. |
| Glue and finishing materials incompatible. | Check with adhesive and finish suppliers. | |
| Varying moitsture contents of wood at time of gluing. | Check kiln schedule. | |
| Oversanded (scoured). | Cunsult abrasive supplier. | |
| Sunken joints. | Allow time for glued off stock to equalize before processing. |
| Warping | Unbalanced construction. | See U.S. Forest Products Lab #2197. |
| Unbalanced finishing. | Seal underside of panel. | |
| Unbalanced moisture content of components. | Bring all parts to equilibrium before gluing. |
| Telegraphing | Dirt, chips, etc., on core or in adhesive. | Keep laminating area clean. |
| Surface defects on core material. | Clean and inspect cores before laminating. | |
| Differential density in core (e.g., lumber banded particleboard to core). | Press at minimum safe pressure. Check thickness of band relative to core. |
| End Checking | Stock at too high moisture content when glued. | Check kiln schedule. |
| Starved joints. | Avoid hollow joints. | |
| Wood not sized. | Check kiln schedule. |
| Blisters (decorative laminate) |
Variation in core caliper. | Check Coating uniformity face and back. |
| Glue line skip. | Check Coating uniformity face and back. | |
| Localized pressure. | Check Coating uniformity face and back. | |
| Steam pockets. | Reduce spread rate/press temperature. |
| Loose Veneers | Insufficient pressure due to extended closed assembly or core too dry. | Reduce closed assembly time. |
| Poor bond but glue on both surfaces. | Increase pressure. |
| Loose Corners | Insufficient pressures or press time. | Increase pressures and/or press time. |
| Lumber bands under size. | Make lumber bands same thickness as core. | |
| Core edges undersize. | Check caliper of edges to give less than 0.005" variation. |