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Quick Easy Waterproof Flashlight using an inner tube

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Picture of Quick Easy Waterproof Flashlight using an inner tube
Electricity and water are never a good thing to mix, but you never want to be caught out in the dark without a flashlight. Whether you're just a hiker and worried about rain, or prefer to canoe or kayak and are constantly worried about ending up in the drink, a waterproof flashlight is just as cheap and easy to make, as it is to buy.

Disclaimer: Water and electricity are a bad combination. It can short out your equipment, and depending on what it is it can give you a decent jolt. While I have made and tested this flashlight take everything said with a grain of salt and some common sense. Always be careful when putting dangerous elements together.
 
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Step 1: What you need

Picture of What you need
A few things to consider. Stay away from self sealing tires. They are lined with a slime that is forced into punctures where it will harden. Needless to say, that would become a horrific mess if you try to cut it. If you don't have any tubes with holes in them you could always consider upgrading and then having the old inner tubes to play with, and if you do have a tube with a hole then you of course want to use a section that isn't pierced for this project.

Materials:
Flash Light
Inner tube from a bicycle
needle and thread
clear plastic bag
super glue

Tools:
Utility knife or scissors
clamp

Step 2: Measure twice, cut twice

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Any kind of flashlight will do. One that is slimmer will be easier to fit the rubber around, but depending on the type of inner tube, and how well used it is, the rubber will be willing to stretch. Just measure your flashlight, and then measure out a length of tubing about an inch and a half or two inches longer. After that just cut the tube to length.

Step 3: Sealing the back end

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Because batteries and water never play nice, this flashlight will need to be sealed up tight. Take the extra inch and a half or so of material on the back end, and glue the insides together. Go ahead and clamp it, wiping up any excess. Airtight is watertight, so if one end is shut, there is less to worry about. After the glue has set, just for some extra insurance I stitched around the edge, staying within the glued area, with a double layer on the inside edge by the flashlight.

Now this could easily be shortened, but I added the extra on so that I could cut a loop for a lanyard or clip. 

Step 4: Putting things together

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Now we can go ahead and slide the flashlight into the tube. Depending on how big your flashlight is, it can be a good fit, or a little snug, either is okay. For me, the body slid in without much difficulty, although I did have to roll a collar, and then unroll it over the head of the flashlight.

One step I did forget to photograph, and it should be done no later than covering the head of the flashlight. Take the plastic bag, I used a plain sandwich bag, and cut out a small corner. unscrew the head of the flashlight and cover the bulb and the tip with the plastic bag. It should extend past the threading for the head, as when you screw it back on, that will provide extra insulation for the electronics against the elements.

Step 5: Finishing up

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Once you have the bulb covered with the plastic, and the head screwed back on, unroll the collar, rolling it up over the head. Trim any excess that obscures the beam, and you should have a waterproof flashlight thats willing to go anywhere you take it.
any tips on getting the innertue on? mineral oil? is really hard to pushup it on.
roll it up and roll it on like a woman's stocking.
annagail4 years ago
Seems like you'd need a flashlight with a button toggle rather than a switch or twist style on/off mechanism.
ElusiveGreen (author)  annagail4 years ago
Very true. Something I hadn't mentioned because I did have the push button design myself. To note, though: having this design, there is some flexibility in the tubing. It would be my assumption that it may not affect a slide switch, or even a twist. I have managed to adjust the focus of the beam by twisting the cap while it is in the sleeve.
Monkeyboy134 years ago
so water doesnt leak in from the front lens of the light?
ElusiveGreen (author)  Monkeyboy134 years ago
There is a thin piece of plastic, like a ziploc bag, that is inside the head of the flashlight, covered in step 5. It covers the bulb and actually passes back to the threads where the head screws on. With the head screwed on it seals itself. It may leak in from the front of the lens, but no water gets into the wiring.

I actually would've preferred the plastic to be external, but I ran into some difficulty with keeping it on, and pulling the rubber over it, so I adapted slightly. I'll try to get around to taking the pictures for that part.
Nifty! Have you tried welding the end together, or does cement work better?
ElusiveGreen (author)  JamesRPatrick4 years ago
I didn't try welding, because the only decent tool I'd have for that is a soldering iron, and I'd be afraid of not getting a consistent seal throughout. Maybe with a hot air gun that would work. You'd just want to make sure its uniform throughout.
I think he was being sarcastic.
Nope. You can weld metal, plastic, rubber, all sorts of things. Pretty much anything that melts(chocolate!).
lol attempt an arc weld on chocolate!
ElusiveGreen (author)  prodo1234 years ago
Now that would be an awesome instructable
LOL no.
ElusiveGreen (author)  prodo1234 years ago
I think when he said welding he meant melting the rubber together compared to gluing it. Not anything with welding the flashlight. So it is a good idea if you have the tools to do it right.
if it could be charged while sealed by induction . That might be cool . The gas produced by batteries should be taken into account also in a 100% sealed app . maybe a 1 way valve ?
redcore44 years ago
could you use a hole punch (like the ones you use to file papers to make the hole? a more perfectly round hole will handle stresses better (as well as being one less step for playing with knives), and be less likely to tear. it's been years since i last played with an inner tube, so i'm not sure if the rubber will be too thick for this?
ElusiveGreen (author)  redcore44 years ago
I think it would be more of a matter of can you get the punch around it. The rubber seemed to cut pretty readily with scissors and the like so that shouldn't be a problem.
prodo1234 years ago
What if you have one of those goo-filled tubes...and need to replace batteries? GROSS.
use non lubricated condoms
Spokehedz4 years ago
This is a nice trade off between a permanent solution like filling the flashlight with mineral oil (As seen HERE) and the ultra-quick solution that I used to use which was a non-lubricated condom with the end tied in a knot.

Kudos!
CHRISPX4 years ago
I reckon you could do this just as quick using a decent condom. You'd probably have to change it when the batteries went flat mind!
kraM4 years ago
i did this to my mag light (the rubber over the switch was missing when i got it)
ElusiveGreen (author)  kraM4 years ago
I still had the rubber over the switch, but I was pleased that the inner tube actually hasn't effected it. That was my biggest concern; that it'd get stuck in on or off.
cool, any idea how to waterproof a min mag? heat shrink tubing maybe?
bertus52x114 years ago
You've got my vote!
brunoip4 years ago
clever :]