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Stretchy String


Here's something which is very useful, and in fact has a wide range of interesting uses. It's a crazy idea which when put into use has applications of great variety and is quite surprising. Yet, I've never seen this in the shops. You generally have to make it yourself.

Here's how to do it:

Get a car inner tube. (These can be obtained from car tyre places, and are typically available free plus a "Thanks!" for taking the things away!). After their functional working life as round things for rolling around in vehicle tyres, if still inflatable, car inner tubes and truck inner tubes often have a happy retirement being used for messing about on water. If you make such use of these items for such purposes, a special note: This is always done "at your own risk"!

If punctured or otherwise not inflatable, the inner tubes can still be used for making "stretchy string" (bungee), which I'll explain next.

You need a good strong pair of scissors for this. The type used for cutting carpet or other heavy industrial stuff.

The cut is a long spiral. In effect, you are undoing the rubber inner tube like peeling an apple where you can end up with one very long piece of apple peel going round and round and round.

Start cutting the rubber inner tube in an almost circular spiral cut around almost the entire diameter of the outer edge of the tube. So, if the tube is 3ft across, that's a cut around the outside edge for about 9ft long before you need to make the next careful move, which is to miss the bit where you started and instead follow a parallel track about half an inch away from it. This way you can continue round the loop again, and miss the start again by another half an inch next time round. The idea is to get a continuous strip of rubber about half an inch wide and very long indeed.

Take a break every few minutes, and take it easy, so as to avoid getting sore places on your hands.

The choice of axis, going the long way round, helps. This allows the strip to be as near to straight as possible, which is quite good considering you are topologically undoing a toroidal surface!

When you eventually get back to where you started, you don't need to make a perfect job of joining up the loop, as the idea is to make one long straight ribbon of rubber, rather than a giant elastic band. Also, it doesn't matter much what happens to the nozzle, as this is to be carefully steered around so it doesn't interfere with the consistent width and strength of the strip.

The result, after about fifteen minutes of work on a car inner tube, or half an hour of work on a truck inner tube (don't do this all in one stint!) is one long strip of rubber, which from a car inner tube is about 40ft long and half an inch wide.

(At this point it's a good idea to wash the stuff, as it is almost always filthy and smells strongly of rubber. Dish washing soapy liquid is best).

This is where the fun starts.

The stuff has the ability to be stretched to about four times its normal length, and when stretched it exerts a force. Every bit of it exerts a force, and these add up.

So, for example, if you have strong girders on the ceiling and a ton of engine on the floor, you can strap one end to the engine and wrap the other end round the ceiling supports and then round the engine again and so on and eventually the engine will lift off the ground. This happens because all the forces in the stretched strips all add up.

It is possible to tie strange loads onto car roofs and transport them a long way. I have transported a 6ft diameter aluminium dome on top of a small car with no roof rack just by putting a rug on top of the car and then stringing the rubber over the top of the dome and tying it onto the door handles and then over the dome again and again. By using the front and back bumpers and all four door handles as cleats and by using a whole inner tube stretched to about 100ft long, it was possible to successfully transport the dome 60 miles. The only difficulties were the minor inconvenience of having to climb into the car through the window, and a few minor complications associated with the conspicuous nature of the cargo.

By a similar technique a pneumatic mast was strapped to a telegraph pole. This takes imagining scaled up, but is of the same principle as two pencils strapped together with rubber bands. It might sound hard to believe, but the combined force of the multiple stretched turns of rubber caused the mast to be so well strapped on that it was possible to pump it up to 40ft high in strong wind with no sign of risk.

Another application of this stretchy rubber strip is to replace the seats of chairs that have failed. Glass top coffee tables that have had misfortune occur where the glass has smashed, can similarly be adapted. With this kind of application it is important to wind the strip round very gently, as it's easy to put too much stretch in and break the furniture!

A much thinner variant can be used for replacing the heat insulation on saucepan handles. Being rubber it is a good heat insulator, and it can also survive boiling water, but it's obviously not fireproof.

Multiple strands of rubber can be used for making a very strong rubber rope which can be used for many things. As a tow-rope, this avoids the jerkiness of ungiving fixed-length towing cord.

If you are silly enough to risk your life using a rope made from home-made bungee-cord, then you should at least test it with a big sack of stuff that weighs as much as you first, rather than leaping off and then finding you should have made it with more strands.

Key features in the favour of stretchy string are:

Things to be wary about stretchy string are:

The stuff is so useful for so many things, but it requires a learned skill to be acquired to use it well and not get it wrong. As with other useful but dangerous things, such as electricity, good commonsense is recommended! If you know what you're doing, the usefulness outweighs the limitations.


Also see other odd ideas at this site, including bizarre forms of recycling including scrap cars and washing machines. The website has a much more diverse set of things in many different aspects in other categories. If you have happened to visit this site by chance, it's worth bookmarking as it takes weeks to explore it all.