It looks like a tube made of glass but it’s actually aluminum. Well, aluminum with an asterisk beside it — this is not elemental aluminum but rather a material made using it.
We got onto the buzz about “transparent aluminum” as a result of a Tweet from whence the image above came. This Tweet was posted by [Jo Pitesky], a Science Systems Engineer at the Jet Propulsion Lab in Pasadena. [Jo] reported that at a recent JPL technology open house she had the chance to handle a tube of material that looks for all the world like a section of glass tubing, but was billed as transparent aluminum. [Jo] tweeted this because it was an interesting artifact that few people get to play with and she’s right, this is fascinating!
The the material itself is intriguing, and I immediately had practical questions like what is this stuff? What is it good for? How is it made? And is it really aluminum rendered transparent by some science fiction process?
Like most accidents, it happened in an instant that seemed to last an eternity. I had been felling trees for firewood all afternoon, and in the waning light of a cold November day, I was getting ready to call it quits. There was one tiny little white pine sapling left that I wanted to clear, no thicker than my arm. I walked over with my Stihl MS-290, with a brand new, razor sharp chain. I didn’t take this sapling seriously — my first mistake — and cut right through it rather than notching it. The tree fell safely, and I stood up with both hands on the saw. Somehow I lost my footing, swiveled, and struck my left knee hard with the still-running chainsaw. It kicked my knee back so hard that it knocked me to the ground.
In another world, that would likely have a been a fatal injury — I was alone, far from the house, and I would have had mere minutes to improvise a tourniquet before bleeding out. But as fate would have it, I was protected by my chainsaw chaps, full of long strands of the synthetic fiber Kevlar.
The chain ripped open the chaps, pulled the ultrastrong fibers out, and instantly jammed the saw. I walked away feeling very stupid, very lucky, and with not a scratch on me. Although I didn’t realize it at the time, I owed my life to Stephanie Kwolek.
Hackers tend to stash away lots of stuff that seems useless, right up until it saves the day. This includes not just junk in our parts bin but brains full of tips and tricks for the shop. With that in mind, you might want to file away a few of the tips in [AvE]’s video of how he made bulletproof glass for a rainy day.
By his own admission, [AvE]’s video is a little disjointed, and the topic of the bulletproof glass is only covered at the beginning and again briefly at the end. Most of the video concerns the machining of a stout stand for the glass for testing on the range. There’s plenty to learn from the machining, though, and [AvE] is always good for a laugh, so the video is worth a watch. The bulletproof glass itself is part of a long-term project that [AvE] is releasing first to his Patreon patrons – a ridiculously over-built flashlight dubbed “The Midnight Sun”. His first two tries at laminating the Lexan discs were less that optimal, as both brands of cyanoacrylate glue clouded the polycarbonate. Stay tuned to the end of the video for the secret of welding Lexan together into an optically clear sandwich.
As for testing under fire, [AvE] sent the rig off to buddy [TAOFLEDERMAUS] for the hot lead treatment. The video after the break shows that the glass is indeed bulletproof, as long as the bullet in question is a .22LR. Not so much for the 9mm, though – that was a clear punch-through. Still, pretty impressive performance for homebrew.
[Glenn] hasn’t put up action shots, but he did write up how he made his own “Bulletproof” glass. The idea is simple: make a composite sandwich of Acrylic and Polycarbonate plastic. Automotive grade uses a combination of glass and Polycarbonate. Great, now we’ve got one more thing on my list of stuff to shoot.