A gooey substance normally wouldn't seem like it could stop a bullet, but an Air Force Academy cadet has created just that.

Cadet 1st Class Hayley Weir's interest in bullet-stopping materials was piqued when she took a chemistry class at the academy in 2014. The class was given three materials to combine in a way that could stop a bullet.

"Up to that point, it was the coolest thing I'd done as a cadet," Weir, a senior at the academy, told Air Force Times.

The students were given an epoxy, Kevlar and carbon fiber   materials that would harden together to stop a bullet but that could also shatter.

That prompted Weir to come up with an alternative combination of materials that would produce the same result without shattering. The academy put her in touch with a chemistry adviser who wanted to research body armor, and he suggested a shear thickening fluid as an alternative to the epoxy that hardened when dried. The fluid, also known as a non-Newtonian fluid, changes viscosity depending on whether stress or force is applied to it.

This means the material would feel gooey until struck with something, like a bullet   then it would harden enough to stop it.

The idea to separately use shear thickening fluid, Kevlar and carbon fibers as anti-ballistic materials is not new, but they've never been used together.

Air Force Academy Cadet 1st Class Hayley Weir created a goo-like substance that can stop bullets.

Photo Credit: Courtesy photo


Ryan Burke, a military and strategic studies professor at the academy who teamed up with Weir on the project, said he fully expected that it had already been tried before.

"The armor industry is a multibillion dollar industry with people studying this on a daily basis as their main profession," he said.

Weir and Burke did a review of previous studies, but they couldn't find anything similar, he said.

"We knew Hayley had stumbled onto something unique here and innovative," said Burke, a Marine veteran.

They also ran the idea past researchers and chemists at the Air Force Civil Engineer Center, who thought it was a valid idea worth pursuing.

Weir began researching in 2015 and switched majors from chemistry to military strategies, where she linked up with Burke to continue the research. 

In the first few months of testing the goo in 2016, Weir said it kept failing.

"Bullets kept going straight through the material with little sign of stopping," she said.

Weir and Burke watched video footage of the testing and found that when the bullet hit the material, it would balloon backward as the round was caught.

The cadet thought maybe they weren't putting the materials together in the best way, so they redesigned the layering sequence.

Air Force Academy cadet tests bullet-stopping material

The three-component goo hardens when struck.


In December 2016, they had their first successful test.

"From then on, we had a hard time getting the material to fail," Weir said.

They went to the Air Force Civil Engineer Center for a week of testing, and the material stopped a .44 Magnum bullet.

"It's a gigantic bullet — this is the highest caliber we have stopped so far," Weir said.

The team tested 9 mm, .40 Smith & Wesson, and then the .44 Magnum rounds.

Burke said the stronger and faster the round, the quicker it was stopped by the material.

In the 9 mm testing, the rounds went through most of the layers but were caught by the fiber backing, Burke said. The larger .40-caliber round was contained in the third layer of Kevlar. The .44 Magnum was caught in the first layer.

"The greater the force, the greater the hardening or thickening effect" of the material, Burke said.

Weir said they're looking at the possibilities of using the material as extremity armor as well as coating vehicles and aircraft in it.

The possibilities are endless, she and Burke said.

The material could be turned into tents that would protect people from small-arms fire and shrapnel, she said.

In the civilian world, it could be used as emergency barricades. For example, if there was a mass shooting, some form of the material could cover people to protect them.

After Weir graduates from the academy this month, she will continue her research at Clemson University in South Carolina.

In the meantime, there's a patent pending on the material that will last 12 months.

Weir said she and Burke will use that time to optimize the technology so it will be more advanced when they file for the official patent.  

Charlsy Panzino covers the Guard and Reserve, training, technology, operations and features for Army Times and Air Force Times. Email her at cpanzino@militarytimes.com.