Troubleshooting: Understanding and Managing Gelatin Glue Viscosity

Gelatin glue, also known as protein glue, is a staple in many industries, including woodworking, bookbinding, and packaging. It’s prized for its strong bonding capabilities, non-toxic nature, and eco-friendly composition.

One key factor influencing its performance is viscosity. If your glue runs too thin or thick, it can lead to poor application results, slow production, or defective products. In this blog, we will explore what causes gelatin glue viscosity to fluctuate and how you can address it to ensure smooth operations.

What is Gelatin Glue Viscosity?

Viscosity refers to the thickness or flow of a liquid. For gelatin glue, maintaining the right viscosity is crucial for optimal application. If the glue becomes too thick, it will not flow properly through the machine, leading to clumping and uneven distribution. On the other hand, if it becomes too thin, it might run too freely, creating weak bonds and even dripping off the material.

Performance Issues Due to Improper Viscosity:

• Poor bonding strength
• Messy application, causing waste
• Longer setup and drying times
• Inconsistent results, potentially leading to product defects

Common Causes of Thick Gelatin Glue

When gelatin glue runs too thick, the issue often stems from the following factors:

1. Under Dilution of Glue
   Gelatin glue is typically diluted with water to achieve the proper viscosity. If not enough water is added, the glue can become overly thick, leading to poor application and inconsistent bonding.
2. Water Evaporation
   Water evaporation is another common cause of glue thickening. If the glue is left exposed or in a machine for too long, the water content will slowly evaporate, increasing the glue's viscosity.
3. Low Temperature Settings
   Gelatin glue requires a precise temperature range to perform optimally. If the temperature in your machine is set too low, the glue will start to thicken, making it difficult to apply smoothly. 

How to Fix Thick Glue

• Dilute the Glue: If under-dilution is the issue, adding more water in small increments will help bring the glue back to the proper viscosity. Always consult the Technical Data Sheet (TDS) for the recommended dilution ratios.
• Check the Temperature: Review the temperature settings on your machine. Increasing the temperature within the recommended range (typically around 140°F to 150°F) can often resolve the issue of thick glue.
• Reduce Evaporation: Cover the glue reservoir or minimize the glue’s exposure to air when not in use to prevent evaporation.

Common Causes of Thin Gelatin Glue

While thick glue can be problematic, running your glue too thin presents different challenges. A thin adhesive is often the result of:

1. Excessive Water Dilution
   Adding too much water during the dilution process can lead to a glue that flows too easily. This results in poor bonding strength and can create a mess during application.
2. High Temperature Settings
   The glue can become overly fluid when the machine temperature is too high. In extreme cases, high temperatures may also reduce the glue's set time or cause the formula to break down, compromising the adhesive’s performance.

How to Fix Thin Glue

• Reduce Water Content: If the glue is overly diluted, add more gelatin glue concentrate to restore the proper balance.
• Lower the Temperature: Check the TDS for the correct operating temperature and adjust your machine’s settings accordingly. Keeping the temperature within the optimal range ensures that the glue retains its appropriate viscosity.

Best Practices for Managing Gelatin Glue Viscosity

A mil depth gauge being used to measure glue thickness.

Here are some best practices to ensure your gelatin glue stays within the optimal viscosity range:

Monitor Machine Temperature Regularly
Machine temperature plays a crucial role in maintaining the correct glue consistency. Always monitor and adjust the temperature to meet the recommended guidelines in the glue’s TDS.

Keep the Glue Covered
Reducing exposure to air can help prevent water evaporation, which is a common cause of glue thickening. Always cover the glue reservoir when not in use.

Dilute Wisely
Follow the dilution guidelines provided in the TDS to ensure the correct water-to-glue ratio. Avoid adding too much water, which could thin the glue, or too little, which could cause it to thicken.

Regular Maintenance Checks
Regularly inspect your equipment to ensure that it’s functioning properly. Faulty temperature controls or worn-out parts could cause glue to run too thick or thin.

Frequently Measure Glue Thickness

A great way to ensure you’re applying the correct amount of glue is to measure it with a mil depth gauge. This little metal comb allows operators to measure the film thickness during application. Discover how to properly use a mil depth gauge.

When to Consult an Expert

If you’ve tried the suggestions above without success, it may be time to contact an adhesive expert. An assessment from a professional can help diagnose more complex issues that may be affecting your glue’s performance.

At LD Davis, we specialize in providing high-quality, eco-friendly gelatin glue solutions. Our team is available to help troubleshoot any issues you may be experiencing, from glue viscosity to machine performance. Feel free to reach out for assistance or request a glue assessment.