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Cold Press Laminating | Hot Press Laminating | Radio Frequency Edge Gluing | Edge & Face Gluing | Assembly Gluing

Lamination Gluing Guide

Cold Press Laminating

Total delamination with little or no substrate failure
Possible Causes:

Pre-cure (no glue transfer)
Recommendation: Increase glue spread

Low pressure (poor contact)


Recommendation: Increase pressure

Short press time


Recommendation: Increase pressure period


Spotty bond

Possible Causes:

Uneven surfaces
Recommendation: Calibrate cores to uniform thickness and/or increase pressure


Worn Spreader Rolls

Recommendation: Replace or re-groove rolls


Glue bleeds through face veneers

Possible Causes:

Excessive glue spread

Recommendation: Reduce glue spread

Excessive pressure
Recommendation: Reduce pressure

Wrong adhesive type
Recommendation: Please contact our technical support team


Telegraphing of core defects or banding

Possible Causes:

Excessive pressure
Recommendation: Reduce pressure

Uneven or variable thickness
Recommendation: Re-sand core

Foreign material on core

Recommendation: Pre-clean core


Warpage of panels

Possible Causes:

Excessive or unequal spread
Recommendation: Reduce spread, and make sure spread is equal on both sides

Unbalanced construction

Recommendation: Check grain orientation and number of plies

Excessive moisture

Recommendation: 6-8% moisture content recommended


Brilliant white on glue squeeze-out and/or glue line
Possible Causes:

Chalking caused by low temperature
Recommendation: Raise temperature of plant, wood and adhesive above minimum use temperature of adhesive

 

Hot Press Laminating

Spotty bonds
Possible Causes:

Low spread
Recommendation: Increase adhesive spread

Uneven core thickness

Recommendation: Calibrate cores to uniform thickness

Low pressure
Recommendation: Increase pressure

Cold spots in platen
Recommendation: Check temperature with surface thermometer

Glue bleeds through face veneers
Possible Causes:

Excessive spread
Recommendation: Reduce adhesive spread

Excessive pressure

Recommendation: Reduce pressure

Wrong adhesive type

Recommendation: Please contact technical support

Steam blisters
Possible Causes:

Excessive spread
Recommendation: Reduce adhesive spread

High moisture content

Recommendation: 6%-8% moisture content recommended

High press temperature

Recommendation: Reduce temperature

 

Warpage of panels
Possible Causes:

Excessive spread

Recommendation: Reduce adhesive spread

Unequal spread


Recommendation: Make sure that top and bottom spread are equal.

High moisture content


Recommendation: 6%-8% moisture content recommended

Unbalanced construction


Recommendation: Check grain orientation

High press temperature

Recommendation: Reduce platen temperature

Checking of Veneer

Moisture content of the veneer and substrate are not equal
Recommendation: Select well-manufactured, tight-cut veneer, keep face veneer within 6% at time of pressing; core components and cross band materials should be held at about the same moisture content as the face veneer; keep assembly time to a minimum.

 

Radio Frequency Edge Gluing

Undercured joint/glue line still wet
Possible Causes:

Low power

Recommendation: Increase power

Short cure cycle
Recommendation: Increase cycle time

No pressure


Recommendation: Check filler boards and pressure system

High moisture content

Recommendation: 6-8% moisture content recommended

Improper catalyst mix

Recommendation: Please contact technical support

Generator malfunction
Recommendation: Contact equipment repair company

 

Cured joint-weak bonds
Possible Causes:

Slightly under-cured
Recommendation: Check power and time settings

Incorrect pressure
Recommendation: Check edge pressure

Irregular or burnished surfaces
Recommendation: Check surface preparation

Improper moisture
Recommendation: 6-8% moisture content recommended

 

Panel open on ends
Possible Causes:

Poor stock preparation
Recommendation: Check quality of gluing surface/end fit

Pressure shoes overlapping on next panel

Recommendation: Check and correct if necessary

Shrinkage between time of surfacing and pressing


Recommendation: 6-8% moisture content, 30% minimum relative humidity and glue within 24 hours of preparation

Burning in joints
Possible Causes:

Power too high
Recommendation: Reduce power

Improper catalyst level
Recommendation: Please contact technical support

Surface irregularities


Recommendation: Check surface preparation

Excessive spread

Recommendation: Reduce glue spread

Long assembly time


Recommendation: Press within five minutes

High edge pressure

Recommendation: Reduce edge pressure


Black glue lines
Possible Causes:

Iron contamination in adhesive
Recommendation: Isolate and eliminate contact source of wet adhesive with iron or steel

 

Edge & Face Gluing

Weak joints with little or no wood failure
Possible Causes:

Poor stock machining
Recommendation: Check for mechanical malfunction, check adjustment of equipment and make sure blades are sharp

Burnished surfaces


Recommendation: Increase feed rate on moulder/jointer and sharpen or replace cutter blades

Undercured or frosted joints caused by low temperature

Recommendation: Raise plant and stock temperatures

Undercured or frosted joints caused by short clamp time

Recommendation: Increase clamp time

Undercured or frosted joints caused by high moisture content

Recommendation: 6-8% moisture content

Undercured or frosted joints caused by thick glue lines
Recommendation: Check part fit and/or increase clamp pressure


Splits and/or open joints on ends of panels
Possible Causes:

High Moisture Content

Recommendation: 6-8% moisture content recommended.

Dry conditions in plant

Recommendation: 30% minimum relative humidity; use end sealer

 

Wood failure only over part of surface
Possible Causes:

Uneven pressure applied to top or bottom only
Recommendation: Apply pressure to top and bottom equally

Uneven pressure due to improper clamp spacing

Recommendation: Apply pressure near ends and 8-12" apart

Uneven pressure due to poor machining

Recommendation: Make sure that surfaces are flat and square

Uneven glue application


Recommendation: Coverage must be even over entire surface

 

Weak joints with wood failure along glue line
Possible Causes:

Grit of abrasive too coarse
Recommendation: 60 grit or higher recommended

Dull saw blades
Recommendation: Sharpen blades

Black glue lines
Possible Causes:

Iron contamination in adhesive
Recommendation: Isolate and eliminate contact source of wet adhesive with iron or steel

 

Brilliant white on glue squeeze-out and/or glue line
Possible Causes:

"Chalking" caused by low temperatures
Recommendation: Raise temperature of plant, wood and temperature above minimum use temperature of adhesive

Assembly Gluing

Weak joint
Possible Causes:

Loose part fit

Recommendation: Part should fit snugly but not require undue assembly force

Joint design (dowels too short, etc.)
Recommendation: Redesign joint

Glue setting too quickly/too slowly
Recommendation: Please contact technical support

Insufficient glue coverage

Recommendation: Apply uniform coating of glue to all parts of joint

Burnished surfaces
Recommendation: Sharpen cutter blades

Overspray of finish on gluing surface
Recommendation: Remove finish before gluing

Undercured or frosted glue lines due to low temperature

Recommendation: Raise plant, wood, and adhesive temperature

Undercured or frosted glue lines due to short clamp time

Recommendation: Increase clamp time

High Moisture Content

Recommendation: 6-8% moisture content recommended

 


Black glue lines
Possible Causes:

Iron contamination in adhesive
Recommendation: Isolate and eliminate contact source of wet adhesive with iron or steel

Brilliant white on glue squeeze-out and/or glue line
Possible Causes:

"Chalking" caused by low temperature

Recommendation: Raise temperature of plant, wood and adhesive above minimum use temperature of adhesive