How to Make a Thermos at Home

“Thermos” is mostly known as the brand name for a particular type of  thermal insulated container but in the same time a thermos bottle also means  an insulated device, designed to keep food or water either cold or hot. Such a thermos consists of  a watertight container placed inside another container with some type of insulating material placed between them. The inner container of a typical thermos bottle is generally made of glass or plastic while the outer part is, in general, made of metal.

Making your own thermos for frequent use is not something we would recommend due to the wide variety of models available to buy these days- that satisfy any demands in looks or prices. But if you are particularly frugal or maybe want to teach your kids the principles of heat transfer and thermos isolation or help them with their science assignments it could turn out to be a fun project. There are plenty of sites or YouTube videos to help you get the best results.

Things You Need To Make a Thermos at Home


  • 1 soda bottle of 2 l (plastic)
  • 1 bottle 1 liter (Preferable made out of glass or aluminium)
  • Masking tape
  • A small amount of all-purpose glue
  • Insulation materials, such as sand, foam beads,isolating Polyfill/or foam
  • Scissors

Step 1:

Make sure the bottles are clean! Cut the top of the two-liter bottle with scissors to make them roughly the same height as the one-liter bottle. Use the larger bottle outside the insulated flask. Apply tape around the cutting edge to protect you from accidental injury.

2nd step:

Paste the 1 liter bottle in the center of the two-liter bottle. Let the glue dry.

Step 3:

Fill the area between the two bottles with one of three insulating materials: sand, foam beads, such as those in a beanbag, poly-fill insulation or foam, which can be found in a craft store.

Step 4:

Use tape to secure and bring together the 2 bottles and to make sure the isolating material stays in place. The thermos is ready to use. Enjoy!

Also you can check out these helpful YouTube videos in how to make a thermos at home:

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