A striking video appears to demonstrate an explosion via the diesel effect in clear ballistic gel. The diesel effect or “dieseling” refers to when a substance ignites from the effects of pressure, and it’s the operating principle behind the gadgets known as Fire Sticks or Fire Pistons.
Ballistic gel is a broad term referring to a large chunk of dense gel generally used in firearms-related testing to reliably and consistently measure things like bullet deformation, fragmentation, and impact. It’s tough, elastic, and in many ways resembles a gigantic gummi bear. Fans of Mythbusters (or certain DIY railguns) will recognize the stuff. Water-based blocks made with natural gelatin can be easily made at home, but end up with a yellow-brown color and have a limited shelf life due to evaporation. Clear blocks exist that are oil-based and don’t dry out like the water-based ones. It’s one of these that is in the embedded animation below.
Slow motion video capture is a natural companion to just about anything that you’d need ballistic gel for, and good thing — because the video captured what appears to be a diesel effect! The block is hit with a bullet, and as the bullet rapidly expands and dumps its energy into the gel, a cavity expands rapidly. During this process, some of the (oil-based) material in the cavity has been vaporized. After the expanded bullet exits (to the right of the gif above but easier to see in the video below), the cavity in the block begins to collapse. The resulting pressure increase appears to ignite the vaporized material, which explodes with a flash followed by some exhaust.
This effect has been observed in ballistic gel before, but this video shows a particularly clear ignition, followed by a secondary expansion of the cavity, then a flatulent-ish ejection of exhaust as the cavity collapses. If nothing else, it’s a very striking effect clearly captured on film. Slow-motion capture of destructive forces makes visible many things that would otherwise happen too quickly to perceive.
Continue reading “Watch The Diesel Effect In Ballistic Gelatin”
On the morning of September 26th, 2013 the city of Orlando was rocked by an explosion. Buildings shook, windows rattled, and Amtrak service on a nearby track was halted. TV stations broke in with special reports. The dispatched helicopters didn’t find fire and brimstone, but they did find a building with one wall blown out. The building was located at 47 West Jefferson Street. For most this was just another news day, but a few die-hard fans recognized the building as Creative Engineering, home to a different kind of explosion: The Rock-afire Explosion.
Many of us have heard of the Rock-afire Explosion, the animatronic band which graced the stage of ShowBiz pizza from 1980 through 1990. For those not in the know, the band was created by the inventor of Whac-A-Mole, [Aaron Fechter], engineer, entrepreneur and owner of Creative Engineering. When ShowBiz pizza sold to Chuck E. Cheese, the Rock-afire Explosion characters were replaced with Chuck E. and friends. Creative Engineering lost its biggest customer. Once over 300 employees, the company was again reduced to just [Aaron]. He owned the building which housed the company, a 38,000 square foot shop and warehouse. Rather than sell the shop and remaining hardware, [Aaron] kept working there alone. Most of the building remained as it had in the 1980’s. Tools placed down by artisans on their last day of work remained, slowly gathering dust.
