Tech Tips from Permabond

Permabond Engineering Adhesives
Glossary of Cure Terms

Fixture time: This is the time it takes before two substrates (adherends) being bonded together can no longer be “wiggled.”

Handling time: After the adhesive has been applied and the joint assembled and clamped, the handling time is the point at which the clamps can be removed and the joint is strong enough to hold itself in position with no additional load placed on it. Consult the Technical Data Sheet for more information. 

Working strength: The time the adhesive takes to reach sufficient strength to be put into light operation. To quantify this, it would be the point where the adhesive is at roughly 60% of its final bond strength. The adhesive joint should not be overloaded or unduly stressed.

Full strength or full cure: Generally this is the time the adhesive takes to build up to its full final strength. Although these terms are often used interchangeably, with some adhesive chemistries, there can be a difference between the full cure time and the time it takes to build up its final strength. For example, many UV Curable adhesives can be completely cured in 2-4 seconds, yet will continue to develop strength for up to 24 hours. Engineering note: The additional strength development isn’t curing – but simply a result of all those polymer chains relaxing into a comfortable position.

The practical use of this information varies with each application. Differences in substrate selection, gap, temperature and other factors affect the results. Remember with all these terms, the values quoted on technical datasheets state a specific temperature, gap and substrate. Variations in temperature, gap and substrate can change the cure value. Testing for cure times on actual components is always
recommended.

Leave a Reply

Your email address will not be published. Required fields are marked *