Yo, Derik here.
This is a quick blog to touch on an issue I hear every so often from people with glue problems (believe me, I've heard EVERYTHING).


Let’s review quickly on how glue works. We’ve got so much information on our site explaining it all, this is not in this blog. If you don’t know what I’m talking about, check it here:
+ heaaaaps more.
So it’s water that makes our glue work. When we train our students, we say we need to get the humidity in the right range for it to work. That’s completely true, but there could be an instance when the humidity machine (hygrometer) says everything is fine, but the glue just isn’t working. WTF, it must be shitty glue! Nope, there’s just something you might not understand about water and humidity.


My job is all things science, so let’s do another science lesson, yay! Don’t worry, it’s not that complicated. The subject today is Relative Humidity. Relative to what? Why is it shown as a percent (%)? Simply put, how much wood could a woodchuck chuck…just kidding.
How much water does the air have compared to how much it could have? That percentage is what the hygrometer shows. 
Hot air can hold more water than cold air. Hot air is like a bucket. Cold air is like a shot glass. If you filled up each container halfway, the machine would say 50%, but one container has wayyy more actual water there. Remember that we’re doing science when we’re lashing. We need water to set the glue, but more specifically we need the right amount of actual water. 
Let’s do a practical example. Let’s say you are baking a cake. You need the correct amount of flour in your cake relative to the other ingredients. How much actual flour you put in the mixture matters. How much actual mixture matters depending on the size of your cake pan. In this example the cake pan is our room temperature. A warm room is a big cake pan, a cold room is a cupcake tin. You won’t be able to feed the whole birthday party of snot-nosed little brats on one cupcake, you need a whole cake.
Some lash techs read the hygrometer and it says 55% and think they’re all good, but the lashes aren’t sticking or coming off later when they brush them. It could be that the room is too cold. There isn’t enough actual water in the air to make the chemical reaction happen. The cold air can hold 100 units of water, it actually contains 55 units of water (55%). The adhesive needs 80 units of water to work properly. So we heat up the room and add more water. The warm air can hold 150 units of water, it actually contains 80 units (55%). Same reading on the machine, but with drastically different results. 

So get your room environment in the right range 21ºC, 55% humidity for the results you’re after.

That’s it, not too complicated, but could save you a few headaches when it comes to getting your glue to behave 😉