A Comprehensive Guide to UV Glue Cure Time

June 5, 2024

Waiting for glue to harden can sometimes feel like you are watching paint dry. In some cases, it can take hours or even days. If you are in manufacturing, you do not have time to waste.  

Some adhesives set faster than others, but you still need to take the proper steps to get a strong bond. You need to know how long it takes your glue to cure so you know when you can move forward with your production process.  

What Is Cure Time? 

Curing refers to the chemical reaction an adhesive undergoes when it goes from a liquid to a solid. Cure time refers to the amount of time it takes for the adhesive to undergo this reaction and reach its full properties. At the end of the cure time, the adhesive is at its full strength and the bond is set.  

Some adhesives cure at room temperature or with heat. In terms of UV setting adhesives, the curing process is a bit different. They cure with the help of UV light. The hardening time for UV glue tends to be quick as well.  

How Long to Cure UV Glue 

The UV glue cure time may range from a few seconds to several minutes. The exact time it takes UV adhesives to cure will depend on several factors including the: 

  • adhesive 
  • light intensity/strength 
  • distance from the light 
  • amount of UV light exposure 
  • environment 
  • amount of the adhesive 
  • substrates being bonded  
  • surface preparation 

Because of all these variables, the UV adhesive cure time can also change by adjusting these factors. While there is some variability, the cure time for UV adhesives is generally faster than the cure time for other types of adhesives that may range from several hours to even days.  

The UV Cure Process 

To avoid problems, it is important to not only take into account the recommended ultraviolet light glue cure time but also understand how the entire UV curing process works.  

Some adhesives are designed not to cure until exposed to UV light within a specific wavelength range. Under the right conditions, the UV light acts as a catalyst for the chemical reaction that will lead to the adhesive setting and the creation of the bond between the substrates. Sometimes, a second layer is also added for the bond to reach its optimal strength. This process typically involves some sort of UV curing equipment such as a lamp, pen, or machine.  

For best results, it is important to follow the guidelines set out by the specific adhesive you use. If you neglect the outlined parameters for the product, it could lead to decreased bond strength or even bond failure. 

Choosing the Right Product 

The ultraviolet light adhesive cure time as well as the curing process will often vary slightly from adhesive to adhesive. Many of these adhesives are also made for specific applications.  

For example, Loctite 3926 is particularly suited for bonding a variety of plastics including stress-sensitive plastics. On the other hand, Loctite AA 3974 is designed for potting and sealing. It is often used in disposable medical devices. Be sure you choose your adhesive with the application in mind.  

If you are not sure what the appropriate UV glue cure time is or are having issues, we want to help. Our adhesives experts may be able to make recommendations on a better adhesive for your needs or offer guidance on how to improve your production process. Contact us today 

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Frequently Asked Questions

Typically, the UV glue cure time is quick, so it can be easy for people to over cure UV adhesives. In many cases, a little bit of a longer UV cure time will have no effect, but extreme over curing can lead to cracking or degradation of the adhesive or the substrates being used. Plastic is an especially susceptible substrate to negative effects from over curing.  

Bonded under the right conditions and used in the appropriate application, UV glues are supposed to create permanent bonds. Of course, bond failure is always a possibility if the curing process is done incorrectly or the bond is exposed to extreme conditions it is not recommended for.