Troubleshooting
Select the type of adhesive you are facing problem with and click on the question to open our suggested solutions.
Problem | Suggested Solution |
Q.1. Adhesive mostly on one surface due to insufficient amount of adhesive or low running temperature. | A.1. Apply heavier glue film thickness and/or raise temperature. |
Q.2. Adhesives on both surfaces but shows “legs”. Caused by disturbing the bond while still in semi-molten state. | A.2. Check compression, apply cooler, or use faster setting adhesive. |
Q.3. Glossy surface appearance of hot melt. Caused by poor or non-contact of surfaces being adhered. | A.3. Adjust pressure to keep glued surfaces together while hot melt cools. |
Q.4. Easy Separation of bond. Usually a result of improper selection of adhesive. | A.4. Try a more suitable product. |
Problem | Suggested Solution |
Q.1. Temperature too high in tank. | A.1. Lower temperature in tank. |
Q.2. Hot melt charring on side walls of tank. | A.2. Keep tank filled. |
Q.3. Air oxidizing hot melt. | A.3. Keep tank covered. |
Problem | Suggested Solution |
Q.1. Overheating. | A.1. Drain and flush system and lower temperature. |
Q.2. Mixing of incompatible adhesives. | A.2. Check with your Walmark representitive. |
Q.3. Unstable hot melt (if repeated). | A.3. Check with your Walmark representitive. |
Problem | Suggested Solution |
Q.1. Running temperature too low. | A.1. Raise temperature… however, too high a tempperature can affect heat stability. |
Q.2. Stock temperature too low. | A.2. Prewarm stock. |
Q.3. Poor timing or misalignment of carton flap to applicator roll. | A.3. Machine adjustment. |
Q.4. Poor shutoff of nozzle. | A.4. Clean and repair nozzle shutoff. |
Problem | Suggested Solution |
Q.1. Nozzles clogged. | A.1. Clean or repair nozzle. |
Q.2. Remote nozzle in multitude nozzle set-up may be affected by pressure drop. | A.2. 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. |
Problem | Suggested Solution |
Q.1. Poor heat control. | A.1. Use calibrated thermometer, reset thermostat. |
Q.2. Hot melt has poor heat stability. | A.2. 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. |
Possible Cause | Suggested Solutions |
Improper viscosity, solids, applications. |
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Possible Cause | Suggested Solutions |
Improper viscosity, stock, compression. |
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Possible Cause | Suggested Solutions |
Improper viscosity or stock. |
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Possible Cause | Suggested Solutions |
Q.1. Insufficient adhesive | A.1. Increase amont of adhesive being applied. |
Q.2. Porosity or sizing of substrate | A.2. Improper adhesive. Contact sales representative. |
Possible Cause | Suggested Solutions |
Q.1. Not enough adhesive | A.1. Increase amoont of adhesive being applied. |
Q.2. Open time is too long | A.2. Increase machine speed. |
Q.3. Ambient temperature is too hot | A.3. Remedy temperature if possible or increase amont of adhesive. |
Possible Cause | Suggested Solutions |
Q.1. Too much adhesive | A.1. Reduce adhesive amount and or increase compression |
Q.2. High humidity | A.2. Reduce amount of adhesive being applied to compensate. |
Q.3. Ambient temperature is too cold | A.3. Attempt to maintain room temperature for adhesive and substrates. |
Possible Cause | Suggested Solutions |
Q.1. Cold adhesive | A.1. Raise temperature of adhesive/ environment. |
Q.2. Adhesive contamination | A.2. Ensure cleanliness of resevoir, nozzles etc. |
Q.3. Adhesive build up in equipment | A.3. Check and clean all equipment. |
Glossy Appearance |
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Cause | Remedy |
Insufficient pressure. | Increase pressure. |
Prolonged open time. | Reduce open time. |
Adhesive On One Surface Only |
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Poor joint fit. | Improve joint quality. |
Cause | Remedy |
Prolonged open time. | Reduce open time. |
Precure of adhesive. | Check wood moisture content or decrease assmembly time. |
Inadequate pressure. | Increase Pressure. |
Spongy Looks Cellular |
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Cause | Remedy |
Foam in adhesive. | Replace glue. |
Inadequate pressure. | Increase pressure. |
Pressure removed too soon. | Increase press time. |
Chalky |
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Cause | Remedy |
Adhesive, Stock and Surroundings Too Cold. | Warm up plant (65oF) and Stock. |
Blue-Black Stain On Hardwoods |
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Cause | Remedy |
Iron contamination. | Check equipment for contact of adhesive bare iron. |
Thick, Noticeable Glue Line |
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Cause | Remedy |
Poor fit. | Check joint quality. Avoid hollow joints. |
Inadequate pressure. | Increase pressure. |
Prolonged closed assembly line. | Reduce assembly time. |
Prominent Glue Line viewed in incident light. |
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Cause | Remedy |
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 |
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Cause | Remedy |
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 |
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Cause | Remedy |
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 |
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Cause | Remedy |
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) |
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Cause | Remedy |
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 |
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Cause | Remedy |
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 |
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Cause | Remedy |
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. |
Bond Tech Industries
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