Shear Tolerance and Its Applications in the Bubble Industry
A Tale of Four Polymers
In my lab, polymers are everywhere. I use them to make cosmetics and skincare products, and I use a whole other set when I’m working with bubble solutions. One debate that always comes up in the bubble world is whether or not to use power tools to mix your solution. Some bubble artists swear by stick blenders and drills, while others insist a simple whisk is best. I decided to run an experiment to see just how much shear tolerance matters.
In chemistry shear tolerance refers to a substance’s ability to withstand mixing at a high speed- like with a blender. Some materials have excellent shear tolerance while others require a more delicate touch.
The Cosmetic Side
First, let’s talk about a polymer I use in skincare: sodium carbomer. If you’ve ever seen a crystal-clear aloe vera gel, there’s a good chance it was made with this polymer. Sodium carbomer is specially treated to disperse and thicken fairly quickly, but here’s the catch—it’s not shear tolerant. If you over-mix it even slightly the polymer chains break down, and you’ll never get the thickness you’re aiming for.
This makes sodium carbomer great for small-batch makers who stir by hand. But companies making 10,000-gallon vats of hand sanitizer? They use a different, industrial-grade form designed to withstand high-shear mixers without breaking down.
I also worked with a special xanthan gum that has been processed and treated to hydrate quickly under high shear. This is the opposite case—you need a stick blender to disperse it evenly. It thickens solutions almost instantly, making it perfect for applications where consistency and speed matter.
The Bubble Side
On the bubble front, I tested guar gum and Poly-ox WSR 301 (PEO). These are two polymers that bubble makers know well, but they behave very differently when it comes to mixing.
For the test, I dissolved 0.5 grams of each polymer in 250 mL of distilled water. Then I split each batch into two groups:
One mixed by hand with a whisk
One blended with a Cuisinart stick blender (a true high-shear mixer)
I let them all sit overnight and came back to see the results.
Guar Gum
The stick-blended guar gum was thicker and smoother compared to the whisked version. This makes sense—guar gum is widely used in food manufacturing, where industrial mixers spin at high RPMs. It’s generally designed to handle shear and actually seems to perform better under it. Guar gum gets processed, and treated in multiple different ways depending on the application, but the label always reads “guar gum” so pick a brand, and a mixing method that you prefer, and go with it If you have questions about your particular brand of guar reach out to the manufacturer. They often publish technical data sheets that will answer most of your questions..
Neither version seemed to get much thicker overnight, but there did appear to be a slight change.
Poly-ox WSR 301 (PEO)
Here’s where things flipped. The stick-blended PEO sample was thin, watery, and a bit cloudy. The blender introduced a lot of air, which hurt film strength and made it feel less slippery. By contrast, the whisked version—while it initially had a big clump at the bottom where it had settled overnight—was easy to stir in later and ultimately formed a much better, more stable gel. It’s interesting to note that the whisked version was thick within a few minutes, and didn’t seem to get much thicker overnight.
That lines up with what we know about PEO. It’s commonly used as the “comfort glide” strip on razors or in cement manufacturing, where its self-siphoning properties help promote smooth flow, and reduce air bubbles. Neither of those applications rely on high-shear mixing, and need to hydrate quickly. You can’t really let concrete sit overnight, and expect to pour it smoothly the next morning.
The Takeaway
So, whisk or blend? The answer is: it depends on the polymer.
Our Big Bubble Blend uses both guar gum and PEO, and I always prepare it with a whisk. After seeing these results, I’m sticking with that method. If you’re just using guar, though, use whatever method works for you. I don’t see much harm in using a drill, or a blender to mix guar gum into a bubble solution if that’s your only polymer.
The bigger lesson here is consistency. If you want reliable results—whether it’s skincare gels or bubble juice—you need to control as many variables as possible:
Same water
Same temperature
Same ingredients from the same suppliers
Same mixing method
(And yes, I even try to use the same measuring cups.)
Polymers may have their quirks, but if you keep doing what you’re doing, you’ll keep getting what you’re getting. In the world of bubbles, that consistency is what lets you turn a good day into a great show.