A photo of a car's interior with the driver and passenger-side airbags deployed - Georgy Dzyura/ShutterstockIf you've subscribed to Mat Armstrong's YouTube channel, you probably know that he has plenty of experience fiddling with uber-expensive cars that've seen better days. Of particular interest is how he and his team deal with deployed airbags, which, if you're not aware, are not meant to be reusable and, therefore, require replacement. Despite Mat's mechanical know-how and creative thinking, what you likely won't find him doing is replacing the factory airbags with a DIY substitute he cooked up in his garage.However, that's precisely what YouTube channel Turnah81 did — conjure up a homemade airbag and test it in his shed. Part of the experiment was a DIY mannequin and a car seat taken straight out of his personal car, all set up on a sophisticated movable platform. The test highlights exactly why you should never try to build your own airbag — his at-home airbag solution was about as useful as an appendix.Because our YouTube protagonist didn't want to go through all the complicated computer bits, he devised a much simpler mechanism. Using a battery and an inertial fuel-cut-off switch, a rudimentary airbag — fashioned from an old pillow case stuffed into a PVC tube with an olive jar lid — is inflated by supplying compressed air instead of relying on pyrotechnics, as would be the case on a normal factory-supplied airbag. While the first attempt was a resounding failure, he did introduce updates, which improved things but only slightly. Undeterred, he then decided to use good old combustion, setting fire to a combustible liquid to speed up the deployment process — similar to unconventionally filling up or reseating a stubborn tire. The attempt went about as well as you may suspect — it was even slower. The takeaway? Don't DIY an airbag.AdvertisementAdvertisementRead more: Never Jump Start A Modern Car Without Checking For These Things FirstUnderstanding airbags and their DIY challengesA screenshot from the video showing an actual airbag deploying and a DIY crash test dummy. - Turnah81/YouTubeUnlike DIY stuff like swapping out an air filter or changing the oil, airbags are a complicated business. To get a petter picture, it helps to understand how a typical airbag works. When a collision is detected, impact sensors and accelerometers in the car tell the airbag control module to set off a chemical reaction (via the igniter) that rapidly releases nitrogen gas into a bag made from nylon fabric. Older versions mixed sodium azide with potassium nitrate, while many modern airbag systems use guanidinium nitrate and a copper nitrate oxidizer. Although, it's worth pointing out that non-chemical systems and hybrid setups using both compressed gas and chemical propellants are increasingly being adopted. According to the NHTSA, the entire airbag deployment process happens in less than ¹⁄₂₀ of a second.Although Mat Armstrong has reset used airbags — in a wrecked Bugatti Chiron, of all cars — that kind of job is best reserved for professionals and shouldn't be attempted by the average DIY enthusiast. According to AutoTrader, if you don't know what you're doing with regard to airbags, they could deploy during fitment and cause serious injuries. However, if you wish to explore the DIY route — although you probably shouldn't – you can go ahead and buy an OEM airbag unit, rent out some DIY mechanic's tools if you don't have any, and get on with the fairly laborious work, which typically involves removing the old unit, replacing the crash sensors, and resetting the airbag's control module, among other things.Want more like this? Join the Jalopnik newsletter to get the latest auto news sent straight to your inbox, and add us as a preferred search source on Google.Read the original article on Jalopnik.