Troubleshoot
Hot Melt Trouble Shooting |
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Poor Adhesion |
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| Problem | Suggested Solution | |
| 1. Adhesive mostly on one surface due to insufficient amount of adhesive or low running temperature. | Apply heavier glue film thickness and/or raise temperature. | |
| 2. Adhesives on both surfaces but shows "legs". Caused by disturbing the bond while still in semi-molten state. | Check compression, apply cooler, or use faster setting adhesive. | |
| 3. Glossy surface appearance of hot melt. Caused by poor or non-contact of surfaces being adhered. | Adjust pressure to keep glued surfaces together while hot melt cools. | |
| 4. Easy Separation of bond. Usually a result of improper selection of adhesive. | Try a more suitable product. | |
Charring of adhesive |
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| Problem | Suggested Solution | |
| 1. Temperature too high in tank. | Lower temperature in tank. | |
| 2. Hot melt charring on side walls of tank. | Keep tank filled. | |
| 3. Air oxidizing hot melt. | Keep tank covered. | |
Gelling of Adhesive |
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| Problem | Suggested Solution | |
| 1. Overheating. | Drain and flush system and lower temperature. | |
| 2. Mixing of incompatible adhesives. | Check with your Walmark representitive. | |
| 3. Unstable hot melt (if repeated). | Check with your Walmark representitive. | |
Stringing |
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| Problem | Suggested Solution | |
| 1. Running temperature too low. | Raise temperature… however, too high a tempperature can affect heat stability. | |
| 2. Stock temperature too low. | Prewarm stock. | |
| 3. Poor timing or misalignment of carton flap to applicator roll. | Machine adjustment. | |
| 4. Poor shutoff of nozzle. | Clean and repair nozzle shutoff. | |
Adhesive Not Flowing Evenly From All Nozzles |
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| Problem | Suggested Solution | |
| 1. Nozzles colgged. | Clean or repair nozzle. | |
| 2. Remote nozzle in multitude nozzle set-up may be affected by pressure drop. | Increase temperature or pressure slightly. Put larger orifice openings on remote nozzles. Melt down capacity of unit may be inadequate for demand. Raise temperature or add auxiliary pre-melter. | |
Fuming or Smoking |
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| Problem | Suggested Solution | |
| 1. Poor heat control. | Use calibrated thermometer, reset thermostat. | |
| 2. Hot melt has poor heat stability. | Reduce temperature to minimum needed for a good bond. Cover reservoirs or premelters whenever possible. Open pots almost always smoke. Use suction fan over pre-melter or reservoir and exhaust fumes to outside. | |
Water Based Trouble Shooting |
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Poor Penetration |
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| Probable Cause | Suggested Solution | |
| 1. Insufficient adhesive | Increase amont of adhesive being applied. | |
| 2. Porosity or sizing of substrate | Improper adhesive. Contact sales representative. | |
Adhesive setting too quickly |
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| Probable Cause | Suggested Solution | |
| 1. Not enough adhesive | Increase amoont of adhesive being applied. | |
| 2. Open time is too long | Increase machine speed. | |
| 3. Ambient temperature is too hot | Remedy temperature if possible or increase amont of adhesive. | |
Adhesive setting too slow |
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| Probable Cause | Suggested Solution | |
| 1. Too much adhesive | Reduce adhesive amount and or increase compression | |
| 2. High humidity | Reduce amount of adhesive being applied to compensate. | |
| 3. Ambient temperature is too cold | Attempt to maintain room temperature for adhesive and substrates. | |
Poor matching |
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| Probable Cause | Suggested Solution | |
| 1. Cold adhesive | Raise temperature of adhesive/ environment. | |
| 2. Adhesive contamination | Ensure cleanliness of resevoir, nozzles etc. | |
| 3. Adhesive build up in equipment | Check and clean all equipment. | |
Woodworking Adhesive Trouble Shooting |
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Glue Line Appearance |
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| 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 |
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| 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. | Consult Bond Tech Rep. |
| 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. |
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| 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. | |
| 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. | |
Liquid Case and Carton Sealing Trouble Shooting |
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Poor Setting Speed |
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| Possible Cause | Suggested Solutions | |
| 1. Improper viscosity, solids, applications. | a. Check if product has been diluted. | |
| b. Check if product has been stirred thoroughly before use. | ||
| c. Check viscosity increase due to aging. Dilute if necessary. | ||
| d. Check for excessive application, reduce if necessary. | ||
Poor Adhesion |
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Possible Cause |
Suggested Solutions | |
| 1. Improper viscosity, stock, compression. | a. Check viscosity as above. | |
| b. Check for uniform application pattern. | ||
| c. Check compression (too little or too much). | ||
| d. Check for improper scoring which can cause springy flaps. May need faster, tackier adhesive. | ||
| e. Change stock or adhesive. | ||
Excessive Penetration or Holdout |
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| Possible Cause | Suggested Solution | |
| 1. Improper viscosity or stock. | a. Check viscosity as above. | |
| b. Check compression. | ||
| c. Increase or decrease application as required. | ||
| d. Change stock or adhesive. | ||
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 ADBOND 406
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