Sturdy Flask From Plastic Bottles

So, last time I showed how to make a nice post-apocalyptic club or baton using mostly plasic bottles.

This time I want to expand on the topic and show you how to make sturdy flask using only plastic bottles and one clever trick.

As we know plastic bottles are really good for storing water and it's easy to imagine them being readily available in hypothetical post-apocalyptic world. But one plastic bottle is just too flimsy to serve for a long time in harsh environment. So now I'm going to show how to make one plastic bottle embodying the durability of a dozen.

All the materials you'll need are plastic bottles: Few for the main body - shape is irrelevant; and 2 or 4 of similar size with domed round tops. The ones I'm using are 1,25L but take to the account that the resulting flask will be smaller than the initiall bottle.

Of the tools the most important would be the heat gun, but also:

• knife
• scissors
• gloves

Also you may need a plastic bottle strip cutter, like this one, for example.

To begin, take one bottle and skrew the lid on tightly. It's is important that air doesn't leak during the process.

Set a heat gun to 200-300C. Use a glove while using it.

WHile holding the bottle in one hand start applying heat to it in swift motions. At first from further away to gradually heat the air inside the bottle. Then from up close applying swift motions along the bottle while rotating it.

Eventually the shape of the bottle will turn into a drop-like and it'll become hard out of pressure of hot air inside.

Do some job to smooth the bottom as well.

Next, remove some labels from the bottles. The shiny metalized coating is what we're looking for. If your bottles don't have it, you can use an empty pack from potato chips or a regular aluminium foil.

Wrap this material around your flask core. It's NOT crucial for it to be accurate.

Now, cut the top section off from another bottle. Poke series of holes in the bottom for the air to escape. And slide it over the flask core all the way up.

Using the heat gun start shrinking the bottle around the core, startting from the bottom and moving up.

The air pressure inside the core bottle won't let it collapse.

Pay special attention to the bottom and make it shrink close to the core.

Cut a top portion from another bottle and remove the top so it could be slid over the top of the core.

Shrink it with a heat gun and cut off the excessive film material.

Metalized film being shrunk between two layers of PET plastic gives this really cool texture which I like, but also this layer will protect the liquid inside the flask from direct sun rays, which is probably good.

Cut rings, or loops, from remaining sections of the bottle(s) and use them to cover the lacking areas building up multiple layers.

A colar made out of previously discarded bottle top with the lid portion removed is used to reinforce the neck section of the flask.

Build up as many layers as you feel needed.

Although it's a totaly viable option to keep building layers of large smooth sections, I personally prefer to use multiple narrower loops. Not only it makes for an interestin final look but also provides more "grip" for further attachments.

And now to the attachments themselves.

For them you'll need from 2 to 4 domed bottle tops (depending on how many of them you want to have)

After the tops are cut off the bottles, cut the sides portions off to make flaps or "wings". Do not cut too close to the neck though.

To secure the attachments to the flask we'll need to make a special sleeve.

Cut off a straight section of the bottle and crease two sides the way is shown on the picture.

On eachside mark and cut circles about 3cm in diameter. You can use a bottle cap as a template.

Insert the bottle tops into the holes in the sleve from inside. Make sure the "wings" are positioned the right way: when the whole assembly it put onto the flask core the should "hug" the bottle.

Now, shrink the sleve using heat gun. Make sure not to overheat and deform the bottle necks.

If done properly everything should adhere to the core flush and tightly.

These protrusions will be used for attaching a sling to the flask. They deliberately pointing preferably toward one way (the back of the flask) to make it more flush with the body when worn.

To further secure the attachment and provide even more regidity to the final flask multiple rings or loops 1-1,5cm wide are cut out of remaining bottle parts and slid over the body of the flask and around protruding bottle necks in a cross fasion.

Every couple of loops is shrunk with a heat gun.

Build up the layers untill needed amount is reached.

This works fine at the upper section of the flask and requires no additional tools.

If it's imposible to put the loops onto the remaining protrusions a strip can be cut out of plastic bottle using a special cutter.

Then the strip can be lashed around the needed section with horisontal passes used to alternate the direction.

To secure the end of the strip pull it under the existing layers and after the shrinking cut the loose end.

At this point the flask can be concidered finished.

After screwing off the lid and releasing the air pressure, the flask should remain it's shape and due to the composit structure it should have a plenty of strenght. If done properly it should feel wood-like.

And this is how it looks in the light of the day. I like the character and organic unevenness it has and being given a propper weathering it should serve as a neat prop, but also as a totally functional flask.

And here are some prototypes I made earlier. The first one shows how the sling is utilised. This one I made out of old bicycle inner tube, and althought I don't quite like it, it still shows how it works.

Also you can go all the way crazy with the protrusions and create although not very functional (arguably those can be used as containers of sorts) but very cool-looking designs.

In this instructable I tried to show the most basic design that can be done using only one type of bottles, but haven a variety of different shapes and sizes can open wide creative possibilities.

Anyway, this is it for now, thank you for your attention and have a nice flask.