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  • Writer's pictureBaileigh Higgins

Make your very own Homemade Vacuum Flask

How to make your very own vacuum flask.

Scotland may be famous for its drizzly weather, flame-haired residents, and numerous contributions to the world of inventions like penicillin, the TV, and the telephone, but did you know that the vacuum flask was also invented by a Scot? In 1892, the scientist James Dewar designed and invented the very first vacuum flask.

The vacuum flask consists of two flasks with a gap in between them. The gap has almost all of the air removed from it to create a near-vacuum, which in turn prevents heat from being transferred. Now next time you sit down to enjoy a warm cup of tea halfway up a mountain or an ice-cold drink of water after being chased by a horde of zombies, you'll know how your flask works and who to thank.

You can think of a vacuum flask as a water bottle holding another bottle inside it, but the two are separated by vacuum, with a supporting stand at the bottom. This basic structure provides thermal insulation or reduction of heat transfer. A vacuum sleeve keeps liquids hot by stopping the escape of heat through three layers of protection (inner, vacuum, outer) and keeps liquids cold by not letting any heat from outside enter the container, achieved via a double wall of stainless steel.

A vacuum flask is a must-have, a little bit of luxury during the apocalypse. So, what do

you put in your flask? They’re good for keeping any liquids hot or cold - Tea, coffee,

water, cold drinks, and of course, a hot toddy. (Just don’t drink too many!)

How to make your own Vacuum Flask:

  • Select a bottle. Use any plastic or glass bottle with a reusable cap. The bottle should be the right size to hold an individual drink.

  • Under most conditions, glass is a better insulator than plastic. Plastic is cheaper and easier to work with, however, and it does have decent enough properties as an insulator to work on this project. Additionally, it is important that you use a bottle with a reusable cap, and many glass bottles do not have reusable caps.

  • Wrap the bottle in paper towels. Spread out a long sheet of paper towels on your working surface. Center the bottle on one end of this sheet and gradually roll it over the paper towels, wrapping the paper towels around it in the process. Your long sheet of paper towel should consist of several individual sheets still bound together. Use enough material to cover your bottle at least three times.

  • To make the rolling processing easier, tape the near edge of your paper towel sheet to the bottle before you begin rolling the bottle up.

  • Try to keep the bottle straight as you roll it so that the paper towel wraps around the bottle in even layers.

  • When finished, stick a large piece of electrical tape over the open end of the paper towel to hold it down and in place.

Wrap paper towel around bottle.

  • For extra insulation, adhere disposable sanitary towels around the bottle, using electrical tape to seal the gaps between the towels. Wrap the bottle in aluminum fill. Spread out a long sheet of aluminum foil on your working surface. As you did with the paper towels, center the bottle on one end of the foil sheet and roll it over the sheet, wrapping the foil around it as you work.

  • Your aluminum foil sheet should be at least as long as the paper towel sheet you used, if not a bit longer.

  • As you begin, tape the near edge of the aluminum foil to the paper towels on your bottle to hold it in place. Doing so will make it easier for you to roll the foil over the bottle.

  • Continually flatten the foil over the surface of the bottle as you roll. Also, make sure that you roll the bottle in a straight path so that the layers are even.

  • If the foil rips during the wrapping process, apply tape to the rip and continue rolling.

  • Tape the open end of the foil when you finish wrapping the bottle up. Cut away the excess. Use scissors to trim off any excess paper towel or foil sticking out beyond the top and bottom of the bottle. Make sure that enough of the material has been removed from the mouth of the bottle for you to sip from it.

  • As you trim away any excess, keep in mind that the paper towel layer should never be visible from beneath the foil layer. Wrap the bottle in electrical tape. Stick the electrical tape to the top of your bottle, starting at or just above the foil layer. Wrap the tape around the bottle in a downward spiral, bringing it all the way around the sides of the bottle and down to the very bottom.

Wrap insulation tape around foil.

  • Even though the foil may remain on the bottle without the use of tape, using tape provides an added level of security.

  • Black electrical tape is the best choice because it also adds another layer of insulation to your makeshift thermos.

  • Test the thermos. To verify that it works, you should pour hot water into the thermos. Take the temperature of the water immediately after you pour it into the water, then check the temperature in 30-minute intervals after that.

  • If you are satisfied with the effectiveness of your thermos, you can use it as it currently is. If are still unsatisfied, however, try adding more layers of insulation or try a different method of construction.

That's it! Now you can make your own vacuum flask and keep chilly... or hot during the apocalypse. Remember, you’re a survivor.

A Blog Post by Baileigh Higgins.

Information and pictures courtesy of WikiHow!

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