Understanding viscosity (also known as thickness) is crucial for every lash tech, as it directly impacts the performance and application of lash extension adhesives. With so many options available, lash techs often have varying preferences when it comes to the thickness or thinness of the adhesive. However, no matter your preference, it's essential to learn how to maintain and control the viscosity of your adhesive to ensure consistent results. 

What is Viscosity?

Viscosity, measured in centipoise (cps), describes the thickness of adhesive. Generally, thicker adhesives cure more slowly, giving beginners more flexibility, while thinner adhesives cure faster, suiting experienced lash techs who work at a quicker speed. An exception is Orbe Ultimate 1, which combines thick viscosity with fast curing for controlled, efficient application.

How does viscosity feel?

The viscosity of adhesives can vary from 70CPS to 155 CPS. To give you a sense of how viscosity feels, here’s a comparison of different liquids. Water, for example, is very thin with a viscosity of 1 CPS. On the other hand, honey—a much thicker substance—has a viscosity of around 600 CPS when warmed to 60-70°C, while at room temperature, it can exceed 10,000 CPS. See the chart below for a more visual comparison that additionally compares Orbe Ultimate and Perform 2 adhesives.  

Liquid	Viscosity (CPS)
Water	1.0
Milk	2-3
Orbe Ultimate 0	80 -125 (thin)
Orbe Perform 2	110 - 130 (medium)
Orbe Ultimate 1	130 - 155 (syrupy)
Maple Syrup	150 - 200
Honey at 60-70°C	500 - 600

Factors Affecting Adhesive Viscosity

1. Adhesive quality: A primary factor impacting viscosity. Lower quality adhesives often are formulated with cheaper and inferior ingredients such as less pure cyanoacrylate, low-grade PMMA or poor-quality carbon black
1. Less pure cyanoacrylate can lead to unpredictable thickening, shortening adhesive usability
2. Poor-quality carbon black settles quickly, leading to gloopy, inconsistent mixes that require extra shaking
3. Low-quality PMMA can cause clumping, making application challenging and compromising the adhesive’s smoothness.
   
2. Temperature: Temperature is the most crucial factor impacting viscosity. Cold environments thicken adhesives, while warmth thins them. Adhesives exposed to extreme temperatures can become too thick. 
   For example, at a typical room temperature of 20°C, the viscosity of Orbe Ultimate 1 adhesive is approximately 150 CPS (syrupy). As the temperature rises to around 30°C, the viscosity decreases to 125 CPS, making the adhesive as thin as Orbe Perform 2. Conversely, as the temperature drops, the adhesive thickens; at 15°C—more typical of UK weather—it becomes noticeably thicker. At 5°C, it can get as thick as maple syrup. See the chart below that shows exactly what we just discussed:     
3. Improper Mixing: Adhesives may become thicker or "gloopy" if not properly shaken before use. The carbon black ingredient used in black adhesives tends to settle at the bottom if left unmixed, leading to inconsistent viscosity
4. Product Interaction: Using a primer or accelerator on the lash strip can cause the adhesive to thicken prematurely when dipping lashes, leading to "gloopy" adhesive on the strip
5. Improper storage: A prolonged exposure of adhesive stored outside the advised temperature range (typically 5°C- 15°C) can result in unpredictable thickening or performance

Best practices for lash adhesives:

1. Temperature Control: Keep your workspace between 16-24°C to ensure optimal adhesive performance. If it’s too warm or cool, the adhesive may thicken or thin, affecting its effectiveness. Use a digital thermometer or hygrometer to check.
2. Shake Before Use: Shake your adhesive well before each use, especially those with carbon black -- to avoid gloopy, uneven results.Manually shake for 60 seconds or use a glue shaker for 10-15 seconds to maintain a consistent mix.
3. Proper Storage: Store unopened adhesives in airtight containers, away from extreme temperatures. For opened bottles, keep them in a cool, dry spot. Unopened adhesives can go in the fridge but bring to room temperature before use.
4. Use Fresh Adhesive: Set a higher standard than manufacturer guidelines—it’s your client, after all. Use unopened adhesive within 4 months (even if the expiry is 6 months). Once opened, use within 3 weeks for best results. Investing in a fresh bottle is always better than risking treatment quality and client satisfaction.
5. Invest in adhesives made from purer ingredients: Last but not the least, it’s definitely worth investing in a high quality adhesive that is made from pure form ingredients. Here's advice on how to identify a high quality adhesive from Dr. Dan, a leading scientist from the University of Cambridge