Introduction: Emergency Vehicle Escape Keychain

Picture of Emergency Vehicle Escape Keychain

Car accidents. Yikes!
The best way to avoid being in an accident is to use safe driving techniques and always pay attention to where you are going and to other cars around you. However, despite your best efforts you are not in control of other drivers and sometimes accidents happen. Bummer.
There are options available on the market for vehicle escape devices which will help you out in case of an emergency, however a few of the models I have seen are designed to be placed under your seat or in the glove compartment. What these products do not address is that the location of these devices are often inaccessible after an accident or are thrown around the vehicle during impact.

This project will outline a design for a post-accident escape device which will never be further than your steering column. In the case of an emergency, use your good judgement to get yourself to safety.
Be smart and ensure your vehicle is equipped with all necessary safety gear such as tire repair, cones, and road flares. This project is part of a complete car survival kit.
Construct at your own risk.

statement of design:
The design consists of has a small blade located in a narrow channel designed to cut your seat belt should it become jammed, there is also a shard of ceramic which can be used to break your driver's side window allowing you to escape your vehicle if the door has become compromised. An LED can also be fitted allowing you some light if it's dark. The entire device has a non-slip grip made from a waterproof material and can be attached to your car key ring.
This instructable is entered in the Pocket-Sized Contest.
Remember to vote for your favourites!

Enough talk, lets make something!

Step 1: Materials

Picture of Materials
  • spark plug
  • plastic (credit) card
  • 2-part epoxy (or other strong adhesive, must be able to bind metal to plastic)
  • permanent marker
  • hobby knife with 'snapable' blade
  • masking tape
  • sandpaper (I used 3 types: 120 grit for wood, 120 grit waterproof emery cloth, and a stiff hobby board sander)
  • hammer
  • vice grips (grips or clamps)
  • drill (with metal bit)

Knives are serious business. Be safe, and use responsibly.
Spark plug shards are also serious business, use goggles and gloves.

Step 2: Snap Your Blade

Picture of Snap Your Blade

Grab your hobby knife and extend out the blade exposing a few sections. I measured off 2 section with a total length of about 1cm (1/4"), depending on the desired size of your cutter and the type of knife you use yours may look different. The size of the cutting blade will dictate how large your device will be.

Once the blade is extended to the desired length lock the blade in place (seriously, lock that bad-boy down). Place a small piece of masking tape over the exposed blade and press down on an angle on the exposed portion. If done correctly the blade should snap along the scribe, the masking tape prevents the snapped blade from flying out and stabbing you in the face (because we've all been there).

Step 3: Cut Card to Shape

Picture of Cut Card to Shape

Next, use your marker and creative license (you have your license, right?) to design the shape of your belt cutter and channel opening. Since you'll be covering the plastic card you can draw willy-nilly to find that perfect shape. I chose a minimalist design but you could go for whatever shape and size you wanted.
Position the small blade you just snapped over your design to ensure that you have enough room on the card. I recommend maybe going a little larger than you need as sanding the plastic is easy, the metal not so much.

Once you are satisfied with your design cut the card into two blanks, mine measure 2cm x 5.3cm (0.8" x 2") each. Use your hobby knife to carefully rough out the inner channel, this channel is what will guide the seat belt to the blade.

Step 4: Add in an LED

Picture of Add in an LED

Depending on your size and design you can include an LED to your belt cutter.
I had an old bike lock key that had a small LED in the handle, the battery was small and just managed to fit on the cut plastic. Find a good spot and carefully position your LED and battery.

Step 5: Light Sanding

Picture of Light Sanding

Give your cut plastic shapes a rough sanding to take off any burrs and sharp corners. It's easy to get into the tight spots before it's assembled, but don't go too crazy sanding as the final sanding comes after we glue the two halves together.
The only place that needs some roughing is the inside faces of the halves being glued, this roughing allows a stronger bond between these two glossy surfaces.

Step 6: Glue

Picture of Glue

Squeeze out some 2 part epoxy onto some scrap and mix it up. Apply a thin coat of epoxy on one half, gently position the blade and LED assembly, add an extra dab of glue to the other side of the LED and blade then close the halves.

Next cut a few strips of waterproof sandpaper the rough shape of your plastic card, apply another thin coat of epoxy to the underside of the sandpaper strips and cover the outside of joined halves.

Clamp. wait. trim excess with hobby knife and sand all edges smooth.
By waiting until now to do a more thorough sanding you'll even edges on both sides and have a smooth top and bottom.

A word on epoxy:
As with most glue a good rule to follow is "less is more". This means that adding huge gobs of glue does not equate to a better bond. Most epoxy is stronger than the components being glued, using too much will result in a sticky mess with no added strength. Be smart, use enough to adequately cover the area you are working on, when you clamp it together some glue will ooze out but not so much as to glue the clamps to your project.

Step 7: Drill Keychain Hole

Picture of Drill Keychain Hole

After sanding allow the epoxy to completely set (maybe an hour, maybe overnight depending on the type of epoxy used), then you can start drilling the hole to hang your belt cutter from your key chain.

You will need to use a drill with a bit specifically designed for metal, if you use a wood bit you run the risk of damage to your tools, this project, and yourself. Slap on your safety goggles and slowly start drilling.
The reason we're using a metal bit is because we're going to drill through the metal blade inside. Start small with a pilot hole, then change to a large bit and drill again to enlarge the opening.

Step 8: Smash That Spark Plug

Picture of Smash That Spark Plug

We're now going to break our spark plug to obtain a shard from the ceramic insulator.
For safety sake treat ceramic like glass, it splinters and shatters when broken. These slivers can fly everywhere and can embed themselves into your skin if you are not careful.
Wear goggles and gloves!! this is not an option, you are putting your juicy eyeballs in peril.

Put the spark plug inside an old sock to prevent splinters flying when impacted, then take it outside and smack it a couple of times with a hammer, it took me about 3 solid swings to break the ceramic apart. Carefully turn the sock inside out and empty out the broken pieces, select a shard that is small enough to fit on your project.
Ceramic shards have sharp sides which can cut fingers, carefully file down the sharp edges of your shard. Sanding down the sharp edges of ceramics using regular wood sandpaper isn't going to work that well, try using emery cloth instead.
Once the edges are smoothed out mix up some more epoxy and put a dab on the ceramic shard, then place the shard onto the end of your belt cutter.

Through some post-published field tests it's been determined that a smooth rounded surface does not work as well as an exposed edge. Your edge does not need to be as sharp as a razor, so you can sand off the hard edge so it doesn't cut you. I have also discovered that the shard size can be very small, half the size of your fingernail would work. Check out the video in step 10.

there's been some discussion in the comments section regarding the composition of spark plug insulators.
My research has uncovered that insulators can be (and are) manufactured from both ceramic and porcelain. The insulator tip at the bottom of the plug is almost always made from ceramic.
Checking the definition of porcelain it says that it is a type of ceramic, though with a Moh scale rating lower than just ceramic due to the added minerals. This makes porcelain a poor choice for this project, make sure you check before you start smashing.

In any case the idea of this is that we are looking for a ceramic shard to shatter the glass. If you are unsure of the composition of your spark plug insulator you can either use the insulator tip (located at the end of the spark plug) or simply find another source of ceramic. There's a few household ceramics that come to mind, however carrying around a shard from your toilet is kinda gross.

Step 9: Science, Limitations, and Further Reading

Some Science:
The Moh scale measures the hardness of a mineral and it's ability to scratch a softer mineral. On the Moh scale diamond is the hardest at 10, ceramics measure around 9, glass is close to 6.5, and talc is at the bottom with 1. Using this scale we can see that ceramic is harder than glass, which is why a small shard of ceramic can damage glass. If you want to know more about the hardness of minerals why not read all about the Moh scale.
Through ceramic is much harder than glass there are some limitations

Laminated glass:
Laminated glass is glass which has been sandwiched with layers of plastic to allow the windshield to retain it's shape after an impact and prevent it from showering you with shattered glass. You can try to chip the windscreen and shatter it with the ceramic shard and kick out the glass once shattered, but your better option is just to use the driver's side window as they are not usually laminated.

Thick Glass.
If you have bullet-proofed your minivan windows to avoid suburban assassination, or if you are riding in the Pope-mobile this will not work.

Plastic Windows.
Some custom cars and older vehicles use plastic composite windows, it will not work for these types of windows.

Step 10: Action!

Not content to let science and other internet videos make my point for me, I went to the auto wreckers and managed to talk my way onto the site.

The owner was skeptical to the reasons why I was there and asked one of his workers to show me a car I could test it on. While walking along the aisles of cars I asked my escort if he'd heard about ceramics working on breaking windows. Judging by the look he gave me it was like asking a sailor if he'd ever seen water. His exact words were "it's the oldest trick in the book.".

To complete the breaking action there needs to be impact, simply applying pressure to the surface of the glass will not work.
Check out the video below where I toss a shard at the window, the force used was less than what you'd use to clap your hands together.

Step 11: Final Thoughts

Picture of Final Thoughts

You now have a small device which, in the event of a complete wreck, is able to cut your belt, smash your window, and light your escape!

Why not make your own and post the results in the comments? Comments that include a picture of your version of this project will earn themselves a digital patch, good luck!


yokozuna (author)2009-07-29

Mine still needs the spark plug ceramic, but the idea was to make it transparent by using a hard plastic baseball card cover. It would have been better if I hadn't superglued it to myself several times. :)

frenzy (author)yokozuna2010-07-15

This posting has won today's "I Made It" Challenge. For winning you will receive a 3 month pro membership!

Thanks for using instructables!

mikeasaurus (author)yokozuna2009-08-04

thanks for posting your build! I like your material selection for stiffness though maybe incorporating a bright colour as an alternative to my design, as suggested by an earlier comment. Your key placement might also help in belt cutting as there is more to hang on to. nice patched!

yokozuna (author)mikeasaurus2009-08-05

Gracias, sir. The card cover was perfect for placing the blade part, as well as the perfect width for it to fit between. I filled the rest of the inside with super glue to make it stiffer for cutting. The LED is on the same end as the blade, although the button cell still sticks out quite a ways on one side. Also, there is no good way to keep the LED from making contact without bending it quite a ways out. I put a couple of non-car keys on it, and it's small enough I plan to keep it in my car ashtray. I know that goes a little against the "no further than your steering wheel" part, but it's at least close to the same distance. Excellent instructable, I previously voted for it in the contest, and thanks again for the patch!

kicker109 (author)2009-11-14

when you said
"you are putting your juicy eyeballs in peril."
it sounds like you want to eat/have aready eaten them before.

also what part are you refering to when you said juicy?

This is my favorite comment ever.

mikeasaurus (author)kicker1092009-11-18

Having never eaten eyeballs I can only imagine the sensation. However, I had the opportunity to dissect an eyeball once in a highschool science class, it was gross. I remember it gooping out some clear stuff, some things are etched into your mind forever. Weird.

Eyeballs are soft, juicy, goopy and they don't grow back. wear goggles!

shaynes2 (author)2011-06-21

After having undergone my police department's Citizen Patrol training a couple of years ago, it is not advisable to have any kind of ceramic pieces on your person. The PD considers it a burglary tool and will arrest you for possession of burglary tools.

pdub77 (author)shaynes22012-10-22

I find it difficult to believe that any judge would convict a citizen, much less a cop arrest one, for merely having possession of a shard of ceramic, even if that ceramic was clearly intended to break a window. If you had a bunch of stolen goods on you at the time this could possibly be a bad situation, but law abiding persons need not fear. I had a similar conversation with a policeman friend of mine the other day about lock picking tools. This is really just common sense stuff. No cop is going to waste his time arresting you if you are not doing anything wrong. They sell similar tools to keep in your glove box, for crying out loud. =)

slima2 (author)2011-06-21

Seems like a lot of work for a piece of porceline. Wouldn't a Grolsh bottle top do the trick? Can't imagine being arrested for a cute bottle top.

pfatz (author)2011-06-20

If the top metal end screws off as they used to, you would have an instant small point with weight behind it. Should do the job.

Otherwise buy an automatic center punch at the Pawn, FleaMarket, Hardware store or Auto Parts House. Press hard against Tempered Glass Side Window and let the spring do the work with its tempered point. Results almost guranted. Pocket size & cheap.

Mrballeng (author)2011-04-18

"you are putting your juicy eyeballs in peril" I love it!

gearskin (author)2011-01-04

Perhaps if you made the ceramic piece detachable, so It could be thrown separately if needed, increasing the likely-hood that the ceramic hits the window (unless you are a terrible throw). I mean, you would have a ton of chards left at home to replace the chard and it's very unlikely you would need to break more than one car window a day. :P

Skyriam (author)2010-07-10

I've read that the ceramic needs to "impact" the glass, like throwing it, but what about doing some sort of "hammer" movement, holding the keychain and just smash it in the glass. Would that work? Thanks!

GnomeMaster (author)2010-05-06

does  elmors glue work?

GnomeMaster (author)GnomeMaster2010-05-06

never mind i tried it and it didnt work

mikeasaurus (author)GnomeMaster2010-05-09

You'll need an epoxy glue to form the bond. Many epoxies are stronger than the materials they are bonding.

For the example shown here I used a 2-part epoxy, some strong stuff. Post a picture here when you're finished!

kambalax (author)2010-03-18

Maybe a late comment, but for those who ask how ceramic works: For glass to be shattered, you make a scratch on the glass with the ceramic part. Then all you need to do is appliying an impact, as your first scratch serves as a starting point for a complete shattering. Hope it's clear enough.

hardlec (author)2010-03-08

I am curious:  Can the ceramic break a car window while both are under water? 

The idea of usung credid card plastic and a piece of a snap off blade as a seat belt cutter is great.  It will also function as a way to open plastic packages and letters. 

theRIAA (author)2009-12-22

i recommend using binder clips to hold it together while drying! And dont use too much glue around the blade, if it squishes out and covers the very edge of the blade, it's useless. (i made 6 seat belt cutters)

mikeasaurus (author)theRIAA2010-02-22

Some good tips, thanks for sharing.

Any pictures of the belt cutters you mention?

ljuwaidah (author)2010-02-07

I'm not being skeptic, I just don't see how you can use this to break glass easily; it doesn't have a grip you can use to hold it by. What do you do? Just throw it at the window like in the video? What if it doesn't hit the glass with the ceramic part?

Great idea :)

goldenbacon (author)2009-07-17

I just made mine last night, its a pretty awesome rope cutter too.

mikeasaurus (author)goldenbacon2009-07-18

That's great, I'm glad you tried it! If you've completed a project based on this instructable and post a picture here in the comments section you'll get yourself a patch!

goldenbacon (author)mikeasaurus2010-01-24

 Heres Mine, sorry if its a little late in responding to your comment, I ope i still get the patch, haha

mikeasaurus (author)goldenbacon2010-01-25

shazam, you're patched!

starwing123 (author)2010-01-01

I used a part from a filament light bulb, it seems to crack normal glass fine, would it work with car windows?

mikeasaurus (author)starwing1232010-01-02

Step 9 of this instructable covers the limitations of breaking car windows. It really comes down what you use, how and where you strike the glass, and the conditions of the glass itself (lamination, thickness, etc.).

Incandescent bulbs use a tungsten filament (with a Moh of 7.5-8) which is harder than glass. How did you apply the filament to break glass with it being so fragile? I'm interested, do you have pictures to share?

starwing123 (author)mikeasaurus2010-01-02

I don't think I used the filament. I used these old light bulbs that were burned out. I shattered the inside and besides the filament, there was this core that was pretty solid. I'm not sure what it is. The photo of the device alongside with the type of light bulb I used

mikeasaurus (author)starwing1232010-01-09

Since porcelain is used as an electrical insulator it's very clever to think of finding it in a light bulb like the one you have shown, considering many modern bulbs are made with a glass fuse fastened to a metal base.

Thanks for posting your version , it looks good. Have you cut any belts yet for practice?

spylock (author)2010-01-08

This is a good idea,what I do is keep a assisted open pocket knife with a pocket clip,clipped to my pocket,the point of the knife will easily break a side widow with a little bump,and the blade will go through seetbelt like hot butter and you can open the knife with a push of the putton on the spine of the knife requiring only one hand.

Draxis (author)2009-12-24

Instead of a spark plug, could I just go with a nail and use metal, or would this not shatter a window?

jujubeetuna1 (author)2009-10-04

Anyone who knows how glass is to work would know that the ceramic from a spark plug does not always work. It is the concept of all side glass that the middle is the strongest part. I'm 230 lbs and i can jump on a door glass on 8 inch thick concrete and it won't shatter. However if you put pressure to the edges then the glass will break. Should someone try the ceramic they may be burning energy slapping the middle

kicker109 (author)jujubeetuna12009-11-18

i did it too...i was wicked!
the clear stuff is the vitreus humour or aquious humour...and eyeballs are surprisingly hard to slice open with a scalpel
looks cool though

mikeasaurus (author)jujubeetuna12009-10-06

your beginning of your comment suggests that the cermaic portion will not work, while the remainder explains that it works when hit in a certain location.

To be clear, the methods described in this instructable do work, but the glass may require to be struck in a certain location. However I had success (as seen in the video included in this instructable) hitting the glass right in the middle with almost no resistance.

While I agree that the corners of the glass may be the best location, there is a large difference between using a 230lb man and a shard of ceramic. If you require further reading as to why this works you can reread step 9 or follow one of the links I've provided.

DataByne (author)2009-08-01

Forgive me if this subject has already been covered (I'm too lazy to read every comment, but I did do a search of the page), but you should probably make a disclaimer stating that you are not responsible for any damages incurred to property or one's person through the use of this Instructable. Just a liability thing. Otherwise, since you are touting this a safety-tool (a DIY safety tool, yes, but the understood distinction between DIY and commercial is one that is generally overlooked in legal scenarios. You're making a claim to a specific effect, should that effect fail to be as claimed, you could be held liable), you could be held accountable for damages. I'd recommend a nice bold faced disclaimer. On a second note, I don't believe that a ceramic insulator will be sufficient to break even a driver's side window should the car become submerged. Commercial products use a hardened, pointed-mallet like device to overcome the pressure differential that is caused by submersion. I'm not sure exactly how much force needs to be exerted upon a single point of the glass for it to break in these conditions, but it does help if the point of contact is smaller. Perhaps a sharpened ceramic? Mythbusters covered this topic, so the information is probably available somewhere on the interweb. At the very least I'd add another disclaimer mentioning the possibility that this device might not perform the desired effect underwater, until someone can verify whether or not it can or can provide an alternate solution. Otherwise, a well thought out and potentially lifesaving Instructable.

rofl. Anyone who sues an online instructables author for a tutorial gone bad is a jackass. If only I were a judge; I would have more laughs.

JohnMichael (author)2009-07-16

Trying to knock out the front windshield will take forever, and I fail to see how this piece of porcelain is going to help. Side windows are made of tempered glass and much easier to get through than the windshield. However, this still takes an amount of force focused on a very small point. That piece of porcelain is not going to do anything to the window. It would make more sense to use the point of a nail setting punch.

mikeasaurus (author)JohnMichael2009-07-16

Thanks for looking! You should keep reading, step 9 talks about the limitations. Also, this step has also been edited and expands upon the issue of ceramics against glass.

JohnMichael (author)mikeasaurus2009-07-18

My point is not about ceramic verses porcelain. That round piece is not going to do anything against tempered auto-glass. If a person cannot kick out the side window they are certainly not going to get enough focused force to break it with that little round thing. There is a reason the auto emergency escape hammers come to a point. The general concept is good, unfortunately, I do not think that part of it is going to work

mikeasaurus (author)JohnMichael2009-07-18

John, thank you for taking the time to address any shortcomings you think you see regarding this project. Please direct your attention to the newly added step 10 which has a video of the results
Your concerns have merit, as a rounded end will not work as well as an exposed edge, though it does still work. The edge does not need to be razor sharp but does require something more than the rounded end I show in this instructable (though with slightly more force the rounded end would also work).

As discussed somewhere else in these comments, the method of applying pressure will not work, there needs to be a striking action. Holding your keys like nunchucks with the ceramic end loose you can achieve this striking motion and easily break the glass.

You make an interesting point when you mention that commercial available hammers use a point to shatter glass. It is important to also include that these types of hammers have a tip made from hardened steel, not ceramic (though I've seen those too). The point on metal hammers is to focus the striking action and overcome the hardness of the glass (steel has a Moh of 6.5, the same as glass), hammers using ceramic tips which are also pointed are doing so to add that extra dimension and focus the impact further, though as demonstrated is not entirely mandatory.

If you still have reservations about the methods and how well ceramics work against glass and the shapes needed to complete the action then I suggest you locate an auto wrecker and try it yourself, there really doesn't need to be much pressure to get it to shatter, just a direct impact. Thanks again for your insight!

liftcadet (author)mikeasaurus2009-08-26

this my friend is a well thought out and polite reply,well done!

Yea, you'd think that little spark plug couldn't do much damage, but I think he based this idea on "ninja rocks." Check it:

You'd still need a little force, probably, since thieves toss them at the window, but not as much as if you were using something else to break the glass.

you are absolutely correct glueandglitter, the force needed to shatter the glass is less than you'd expect, about the same amount of force needed to produce a clap with your hands. The science of material hardness does the rest!

devynhogan (author)JohnMichael2009-07-20

whenever you break glass you hit it in the corner. tip from firefighter

eardowel (author)2009-07-23

O.K., I'm confused. In an emergency, how do you use that? Surely you don't throw it and hope the ceramic hits the window. Do you flick it or something?

mikeasaurus (author)eardowel2009-07-23

..and why not? Throwing it against the window will shatter the glass provided the ceramic portion makes solid contact. Your design should accomodate your preferred method of striking. Flick, toss, make a hammer-motion, whirl like nunchucks of escape, the key is impact.
The method to achieve the desired results will vary depending on the user (strength & ergonomics).

eardowel (author)mikeasaurus2009-07-30

Well, if it is thrown in hopes of the ceramic hitting the glass, and it doesn't, it's not going to end up back in your hand. It's not a boomerang. We're talking about being in a crumbled car, perhaps on fire.You won't be in any kind of comfortable position. NOTHING will be optimal. It has to work the FIRST time, EVERY time.

mikeasaurus (author)eardowel2009-07-30

Thanks for your concerns, your attention regarding this can not be understated enough. If you feel that your design and assembly skills are not to a standard to which you would want to make this project then you should definitly go and buy a commercially available unit.

mikeasaurus (author)mikeasaurus2009-07-30

...your attention regarding this can not be understated enough.

".. your attention regarding this matter can not be overstated."

About This Instructable




Bio: I'm Mike and I make crazy things at Instructables HQ in San Francisco. Follow me and try a few of my projects for yourself!
More by mikeasaurus:Router Planer10 MORE Woodworking Tricks the Pros UseSliced Wood Coasters
Add instructable to: