Military Gear & Army Surplus Gear Blog

Indestructible Coating?!

Indestructible Coating?!


From the top of this forty-five meter drop tower, my friends from the “How Ridiculous” YouTube channel are about to release a watermelon. Here we are. In free fall for a full three seconds, the watermelon accelerates to over 100 kilometers per hour before smashing into the ground. The results are predictable, but this was just a control for the actual experiment. Another watermelon was sprayed with the polymer coating. Se’ll come back to what this is and how it works, but for now, let’s see how the coated watermelon fares in the drop test. That’s insane! [ laughing ] Instead of shattering, the watermelon bounces and remains intact. For the most part, anyway. It’s a definitly slushy. Even with an axe, the “How Ridiculous” boys can’t crack this shell. How did it not? AHH! [ laughter ] AAH YES Look it’s actually! Look at that! [ laughter ] That is amazing! It is pretty amazing that the watermelon could survive an impact of over 100km per hour! So I went to find out more about the coating, called Line-X It’s a mess! The individual components are a mess, when it goes on it goes on as a big mess you saw me wear a spray suit. It’s a mess! And when you’re done, you get some really cool stuff. Line-X is made from two ingredients, A, and B. Inside of each of these is multiple things. But the main component of A is Diphenylmethane-4,4′-diisocyanate, or MDI for short. It’s very reactive due to these groups on the end. B is the poly. The simplest way I could explain it is that it is a plasticizer. The main component of B is alpha- (2-aminomethylethyl) -omega- (2-aminomethylethoxy) -poly (oxy (methyl-1,- 2- ethanediyl)) A long name for a long chain… molecule. In reality it would be many times longer than this. Now, I managed to convince Brin to let me mix the two ingredients the old fashioned way, with a stirr stick. That’s the A. I’m going to dump A and B in here and just mix them and see what happens. -Ready?
-Yup! Go for it! How quickly should they react? They are reacting right now! Did you see that? That is crazy! You can see there’s almost, like… I don’t know, smoke or something comming up there? It’s probably getting quite warm, I guess I could have gotten the thermometer out for you. Feel the bottom and you tell me. Yeah, that’s very hot. It’s like the bottom of a hot cup of coffee. What’s happening here is that the molecules of A and B are reacting to form long chains. Where they join, they form a urea group so the substance is called a polyurea. The structure of these chains is responsible for the properties of the coating. So it’s hard because it’s made of a tangled mess of molecular threads. But flexible because these threads can be stretched out and then snap back into place. Things you learn doing the reaction this way are that it’s rapid, only taking seconds to react. And it’s exothermic – a lot of heat is given off as these bonds form. But this ball of Line-X isn’t really useful for much, so how do you mix A and B to form an effective coating? Put them under really high pressure, force them together in a really small space. High temperature, high pressure, just ram them into each other. That essentially mixes them. And then they come out the end of the gun. So from the time they’re seperate components, they mix, out the gun, hit your target. Fraction of a second. This is where the magic happens Inside here, see?
Pull the trigger, out comes Line-X We decided to Line-X a piece of paper to see how strong the coating is As you can see it came out as a hot, high pressure liquid. -Ok, now..
-How hot is that? It’s quite warm, and because that’s an exothermic reaction it comes out at 150… But it keeps getting hotter and hotter. You can probably rip it right now. There you go, Ok. Those two chemicals just keep kinda looking for each other, or looking for something, so to speak. Until every last molecule has found a home or given up looking. That could take a day or more. But there’s plenty of opportunities to cross link right now. So that’s what it’s doing. And that’s where all the heat is coming from It’s already dry, I’m not going to get any on me. It’s already cooling back down. So we’ve done the vast majority of curing and cross linking… We’re getting there right? Yeah, it was harder. Now, we wait until some of this heat goes away. We’re probably getting a good amount of curing going on. It is really tough to rip at this point It’s strong stuff That tensile strength will get you! That high tensile strength is the same reason the Line-X coated watermelon bounces As it hits the ground the contents of the watermelon are squeezed out sideways. But the tangle of polyurea molecules pull together. Preventing the rind of the watermelon from deforming too much and breaking apart. So the watermelon bounces instead of smashing. This type of coating is now used in the walls of the Pentagon. Preventing exterior explosions from launching shrapnel into the building. The main cause of injury from explosions. And it’s used in bullet proof vests to contain bullet fragments that could cause serious injury. All of this is pretty incredible for a substance invented as a truck bed liner. Yeah, come on down! Bring your entire vehicle. Anything but your cat. We’ll Line-X it. Massive thanks to the guys over at the “How Ridiculous” YouTube Channel! You know, they are the ones that launched that basketball off the dam. That is my most popular video. And they have been doing some incredible experiments, like “Bowling Ball vs Axe”. So go subscribe to their channel. Go do it right now!


Reader Comments

  1. as you said in your youtube metrics video that talks about the views on the black balls lake, change the title of this one to Indestructable watermelon survives 150 ft fall! and you will get an extra 29 million views. cheers

  2. They just put 2 cm thick stuff over it. If I could cover it with 2 cm steel, you'd see that watermelon crushing into concrete and breaking roads. I don't see a reason for excitement >_>

  3. … klein schwarz stark – verfolge nicht was du nicht zerstören kannst – schwarz wie KALI – all INDIA.

  4. Yeah, it’s only been around for over 30 years. It’s just a polyurea elastomer. There are other companies that make a similar product. Line-X is just a particular manufacturers name!

  5. It kind of seems like that spray stuff the guy sprayed on his feet in cloudy with a chance of meatballs, (the animated movie).

  6. ah yes, who could forget the classic stupidity of bowling ball versus axe…

    oh that's right, me; because I never watched it and don't care to.

  7. Soooo I think the obvious Question is: WHY NOT SPRAY ALL OUR TIRES (inside) WITH THIS… Guess that might slow sales and take away tire repairs.. WOULDN'T THAT BE GREAT-!!!

  8. It seemed as if the coating would be paper thickness. Not an inch thick. You can do this with probably any plastic coating. Hard or flexible if it 1”

  9. 👎🏻👎🏻👎🏻Video thief lmao. You need to say what you say at the end at the very start. Your lame. 👎🏻👎🏻👎🏻

  10. FYI: this substance was NOT invented for use as a truck bedliner. The inventor's goal was a UV and weather resistant coating for polyurethane foam insulation. Closed cell foam polyurethane insulation (think "Great Stuff" canned foam insulation) has been used for decades as a roof treatment for large industrial and commercial flat roofing. The problem is, it's doesn't withstand UV exposure or abrasion very well. The inventor's goal was a weatherproof topcoat system to be sprayed over the polyurethane foam efficiently over a large area, using similar equipment.

  11. What a fantastic visual demonstration of the incredible surface bond strength of Line-X!

    If it can survive the drop test followed by the repeated axe strikes, it's fair to say that it will make an extremely durable truck bed liner or other protective coating.

    Thank you for this informative, scientific, educational and entertaining video, which I greatly enjoyed!

  12. ESSE MATERIAL aí CHAMA- SE GRAFENO NIOBIO DO BRASIL… QUE TANTAS NAÇÕES COBIÇA AS NOSSAS RIQUESAS MINERAIS NÓS BRASILEIROS TEMOS A MAIOR RESERVA DESSE MATERIAL DO PLANETA…🇧🇷🇧🇷🇧🇷🇧🇷🇧🇷🇧🇷🇧🇷🇧🇷

  13. Looked like spray on bed liner Wich can be applied thick enough to repell explosives and the shrapnel created by an explosion

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