How to Make an Air-tight Seal

Updated April 17, 2017

Air-tight seals, whether for preserving food, keeping mechanical parts isolated or insulating interior spaces, can be extremely useful and reduce maintenance costs, minimise spoilage and even lower your utility bills. Fortunately, in each of the above cases, airtight seals are also easy to create with some basic equipment and well worth the small investment of time and tools.

Cover the area where the window frame meets the wall with a thin layer of clear latex sealant. Make sure the sealant covers the full area without any interruptions and use a caulking gun for even application and best results.

Cover the area where the window glass meets the frame using the same technique and sealant.

While caulking a single side of the window should be sufficient to keep air and drafts out, repeat on the other side of the window (facing the outside) to make sure that your window is absolutely airtight and will not let cold air in or warm air out.

Fill a mason jar or canning can with the food items to be canned and preserved.

Bring a pot of water to a rolling boil and place both parts of the mason jar or canning lid in the boiling water for five minutes.

Carefully remove the hot lids using tongs and gloves, place them on the jar or can and seal them tightly.

Allow the can to cool completely and test the seal by pushing up and down on the centre button, which should be held down by the vacuum and not move. Repeat if the lid moves up and down.

Place an appropriately sized O-ring over the opening you wish to seal. Vary the size and shape of the ring to the opening, including non-circular openings.

If you have access to tools and spring clips, fasten the O-ring tightly or use glue to secure the ring and later cover the edges with sealant.

Apply the appropriate cap or matching fixture to create an airtight seal between the ring and the two fixtures.


While one layer of sealant should be enough to hold the seal, reapplying periodically helps to maintain the seal on windows or fixtures. Always verify that canned foods maintain the seal once they have had time to completely cool after 24 hours.


Always exercise caution and use the appropriate safety equipment when handling hot items like heated can lids, toxic items like sealants and potentially dangerous tools such as spring clips.

Things You'll Need

  • Clear latex sealant
  • Caulking gun
  • Mason jar or canning cans and lids
  • Stove
  • Pot
  • Tongs
  • Gloves
  • O-ring and matching cap
  • Glue or spring clips
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About the Author

Edward Mercer began writing professionally in 2009, contributing to several online publications on topics including travel, technology, finance and food. He received his Bachelor of Arts in literature from Yale University in 2006.