TAPPI T821

Introducing TAPPI T 821 – Industrial Physics  

TAPPI T 821 is a TAPPI international testing method to measure the pin adhesion of corrugated boards by selective separation 

This TAPPI adhesion testing approach is used to determine the force required to separate corrugated boards between the flute tips of a corrugated medium and its linerboard facings. 

Why is pin adhesion testing useful?

If you want high quality corrugated board and boxes, then you’ll need good adhesion of the corrugated medium to its facings.  

The pin-adhesion test provides a means of determining the nature and strength of the bond formed during the combining operation and may be used to detect manufacturing defects. These can include:  

• A containerboard with low internal bond strength 
• Poor adhesive penetration 
• Spotty adhesion.  

The TAPPI T 821 pin adhesion test measures the Z-direction force required to separate either the inside, or outside facing, of corrugated boards. 

TAPPI T 821 pin adhesion testing apparatus  

To perform a successful TAPPI T 821 pin adhesion test you’ll need the following apparatus: 

• Pin-adhesion attachment – consisting of pins of the proper diameter and length 
• Compression machine  
• Knife cutter with guides to prepare test pieces. 

TAPPI T 821 pin adhesion testing process

First up, you’ll need to insert some pressure pins midway between the facing and fluted medium. Next, you insert a number of support pins between each of the pressure pins. 

Once you’re all pinned up, it’s time to assemble the test instrument and center it on the platens of the compression machine. Set up your compression machine to apply a load at a constant rate until the facing from the flute tips separates. Separation of all the bond lines is not necessary for a complete pin adhesion test.  

TAPPI T 821 pin adhesion testing devices 

So, how can Industrial Physics improve your TAPPI T 821 pin adhesion testing? 

Crush Tester 17-56 

The Crush Tester 17-56 is suitable for a wide variety of samples, including corrugated board, tubes, corrugated paper and plastics. It features a precision load cell, making it highly accurate, even at low force values. 

Need TAPPI T 821 adhesion testing solutions? Get in touch  

Come to Industrial Physics and we’ll pin down the perfect inspection machine for your adhesion testing needs! We’ve been designing and building pin adhesion testing devices for many years and we’ve learnt a thing or two about paper testing best practice along the way.  

We like to share this expertise across the knowledgebase section of our website where you’ll find blogs like this one – tester tips: pin adhesion testing of board. Or perhaps you’d prefer to stick with this one on adhesion testing insights!   

If you have any further questions, then don’t hesitate to get in touch!  

Your global test and measurement partner for TAPPI T 821