[mindfulhack]

This non-cuttable metal material sounds extremely useful:

> "Security applications such as doors or barriers (as protection from forcible entry attacks) are obvious ones. However, our material technology could also be useful for enhancing the cutting resistance of shoe soles or protective clothing. Workers could benefit from non-cuttable elbow pads or forearm guards in environments with industrial tools."

As someone who cares so much about digital security, physical security feels good.

[db48x]

This material is completely unsuited for making shoe soles or elbow pads; it's a two-inch-thick plate of aluminum foam with half-inch ceramic spheres embedded in it. Around that they welded steel plates to give it a uniform surface.

It'd make a very heavy but uncuttable door, but you can't make hinges or locks out of it. It would be a good material to make safes out of; those already have thick walls of composite materials designed to blunt drill bits.

[throwaway9d0291]

I think that's a premature judgement.

Is there any reason to think that it's impossible to scale it down? e.g. for PPE, 5mm ceramic spheres in a 1cm-thick Aluminimum foam with some 1mm steel plates on either side?

[db48x]

Yes, there is. They hypothesize that this material works because the ceramic spheres vibrate inside the flexible matrix of the aluminum foam, damaging the grinding wheel. A thinner foam will have less ability to flex, and smaller spheres will be have less momentum to use against the wheel.

Plus, if you watch the video of them grinding the material (https://static-content.springer.com/esm/art%3A10.1038%2Fs415...), you can see that the grinding wheel penetrates over half an inch before it begins to be destroyed.

[dgoldstein0]

For comparison I was learning about medieval armor recently. Steel breastplates are about 2mm at their thickest, typically. So that's a rather heavy duty armor idea you have.

Real question then is how it would fare against bullets and piercing attacks. Cutting is only one possible threat, and usually not the biggest threat. Knife resistant bullet proof vest are already a thing, so how would this be better?

[theelous3]

If you make a secure doorway with the hinges on the threat side, well, you're already toast. No need to make hinges out of anything special.

[rudolph9]

I want a bike lock made of this stuff

[8note]

I'm sure lockpickinglawyer will still open it just fine.

[TwoBit]

Yeah but 99% of thieves can't do that. If they could then they'd likely have a real job. Lots of locks are invulnerable to the picking, especially serious digital ones.

[sudosysgen]

They just use a Ramset gun. Thieves are generally quite smart. The dumb ones tend to end up in prison, or worse.

[chongli]

I’ve watched a bunch of lockpickinglawyer videos and there are locks he cannot pick at all, and locks which take a hell of a lot of punishment from a Ramset gun. It’s not out of the realm of possibility that you could build a bike lock which would effectively deter thieves. After all, it doesn’t have to be indestructible, it just has to convince the thief that your bike is not worth the time and risk of attracting attention.

[bosswipe]

One painful lesson I learned after having an expensive bike with an expensive lock stolen is that as you harden the lock at some point the weakest link shifts from being the lock to the thing the lock is attached to.

[Kednicma]

This is a little disingenuous. There exist locks that he cannot pick, but the vast majority of his uploads are three minutes or fewer and include a successful picking attempt. More on-topic for this thread, a common LPL theme is that bike lock chains are made of high-quality hard-to-cut material, but the lock cores are still often commodity parts which are picked open by standard techniques and tools.

I would say that much more important for discussing LPL is that he has immense real-world experience, equivalent to a master locksmith, and he builds his own picks. I am not the best lockpicker, but I bet that even I could open bike locks as quickly as he does, if only I had "the tool that [he] and BosnianBill made" in my fingers. Indeed, the community has talked quite a bit about the tool, and perhaps we'll get a 2020 gift in either a commercially-available version or public specifications for building them at home [0].

[0] https://old.reddit.com/r/lockpicking/comments/atf3ef/so_that...

[toast0]

Ride something from the early 80s, before they went to neon colors.

[ufmace]

I am highly entertained by this, because I just happened to find his videos a few weeks ago and have been watching a ton of them.

[whoopdedo]

"Digital security" is now how I will refer to safety boots and gloves.

[FuckButtons]

Since it uses an aluminum matrix, abrasive cutting may not work, but plasma or gas cutting certainly will. A propane tank and a torch aren’t too difficult to get if someone knew they would need them.