Explosion resistant liner

[Vortus]

As it kinda covers batteries, and led flashlights, and flashlights in general I was not quite sure where to put this thread. Sorry if this is the wrong one.

New to all of the nice flashlight stuff, my wife and I were concerned with the care of our batteries. So we take care of them as shown. However, we have read that sometimes, stuff happens. While researching assorted types of Rhino Liner and Line=X to coat one of my lights, I saw Line-x had anti spall and explosive mitigation liners. Then I got to thinking about the laminates used on armored windows. Would something like that help with safety of flashlights? Esp with the multi battery monsters that manufacturers are coming up with, let along the custom hand held sun's that are being made. Didn't know if anyone was in that field, seems like a nice potential addition to some lights for increased safety. The only downsides I can see are possible slight size increase, it might insulate to much, and the obvious price increase.

 

[alpg88]

As it kinda covers batteries, and led flashlights, and flashlights in general I was not quite sure where to put this thread. Sorry if this is the wrong one.

New to all of the nice flashlight stuff, my wife and I were concerned with the care of our batteries. So we take care of them as shown. However, we have read that sometimes, stuff happens. While researching assorted types of Rhino Liner and Line=X to coat one of my lights, I saw Line-x had anti spall and explosive mitigation liners. Then I got to thinking about the laminates used on armored windows. Would something like that help with safety of flashlights? Esp with the multi battery monsters that manufacturers are coming up with, let along the custom hand held sun's that are being made. Didn't know if anyone was in that field, seems like a nice potential addition to some lights for increased safety. The only downsides I can see are possible slight size increase, it might insulate to much, and the obvious price increase.

well, you missing 1 thing, all those anti explosive spray ons, bulletproof laminates (which wont work by itself) all useless in flashlight, they work to adsorb\redirect shock wave, they work when shock wave has someplace else to go, in flashlight, explosives(batteries are inside the tube, just like shell or grande, or a round, energy\pressure is made inside, it needs somewhere to go, thus it rips flashlight apart (or blows up shel, or pushes out bullet), however there are rounds that lock the gases inside casing, than slowly bleed them, you could build a light based on that principle, but good luck.

lights blowing up extreamly rare occasion, you are a lot more likely get hit by a car, but you don't walk in 4feet thick layer of bubble wrap, do you? just use common sense and you'll be fine.

actually , now that i think more about it, batteries don't blow up like explosive, they are more like black powder, slowly (relatively) build up pressure, all you need is a window to release that pressure, like blow out panels, i know 1 builder drills holes in mag tail cap, and puts a circle of metallized glow in the dark tape over them, if batteries start to produce pressure, the stick on tape will be blown off, and gasses escape.

 

[Vortus]

I was more thinking along the lines of the liner sticking to the inside and keeping it together. It would be junk after, but preventing metal shards from going everywhere like a grenade. Or, with some of the battery tubes, and they would redirect it towards vents. Like D to C mag tubes, or other conversion tubes. But, if it won't work, it won't work.


Not a overly cautious person, but if a simple safety measure can be done at little cost or effort, then no need.


And I like bubblewrap. :D

 

[Walterk]

My first thoughts are a little sarcastic;
Gladly I have other and minor worries to my head then how to prevent a scratch in case I have an exploding flashlight battery to my hand ....

And the chance you have a bullet falling from the sky on to your head on 14th july are bigger :).

To answer your question, prevention is better:
Use a proper batterycharger, preferable with thermal probe that shuts off when overcharging. Monitor with your hand if the batterys are warmer then expected.

The vent sounds sensible. I've read about dive-lights having sponges to absorb some pressure differences as they are closed devices.
The force from the gasses is limited to tearing the housing or blow the end-cap off, probably plastic housings would be safer then metal housings, as they would gently give way on their weakest point.

The idea of foil isnt that bad.
I think racing-cars have open-cell hard foam-filled fuel tanks.
And pressurecontainers often have plastic or steel-wire gazing around them to capture shrepnel. All not apropriatly for flashlights.

To be completely safe: wrap it with woven glass-cloth or kevlar and duct tape on top. If you plan to store it in a shelter for a long time, put a condom over it to keep the moist out (or more impractical a soldered lead box ).

 

[nzgunnie]

As they stand now, most flashlights have a weak point or two...

The bit the light shines through, and depending on the tailcap or switch design, the part with the switch.

Any explosive force will take the path of least resistance, so most lights made of aluminium already have the feature you talk about, since the front will blow out before a structural failure of the much stronger tube.

Lining the tube is therefore pretty pointless, as it's already the strongest part of the light, and the gases will still vent through the much weaker window/lamp assembly part of the construction.

 

[hopkins]

Vortus
Their are a few threads buried in this site that go into gory details
about metal flashlights acting exactly like *pipe%bombs# when the lithium
primary cells went into nuclear meltdown mode.

Drilling a small hole into the flashlight tube to allow venting seems the simplest
fail safe. Pushing a little candle wax into it keeps water out and it
would melt and be pushed out by the heat before the tube goes
critical and injures someone.

Or just stay away from lithium primary's. Worrying about alkaline's leaking
inside a flashlight is less of an ordeal.

hopkins

 

[Brasso]

I would think that making a vent hole in the head, between the body and the lens cavity, would allow excess pressure to vent out through the lens. The lens would of course break, but that would be the least of your worries at this point, and it would keep an airtight seal. A better alternative to plastic lining, imo, would be a ceramic coating inside the battery tube to prevent gas cutting.

 

[Search]

Unless the battery vented slowly, even drilling a hole would do very little. You aren't going to get a big enough hole to let the pressure escape quick enough.

If your batteries fit tight in the tube then you would have to hope explosion originated at the location of the hole. If not, your hole is in the wrong spot.


Lining the inside would do nothing but cause more stuff to shoot out. You would have to bore the light to put the lining on, which would relate to a weaker tube. You see where that's going.


However, lets face reality. The odds of anything going wrong are so slim it's not even worth worrying. I would be more concerned about driving in the car.

Only one thing is going to help you: statistics.

Take it from someone who works with explosives (ie. making explosive ordnance), nothing is going to work except making a light out of some very durable steel.

I'm waiting for the day someones lithium explodes and the battery casing liquefies and blows a hole in the light. Even though it will never happen.