Sealing Cap for Bottles From PET




Introduction: Sealing Cap for Bottles From PET

About: I am an electronic engineer but work as a system analist. I started doing such projects when I was 15 years old. I did some home made photo machines and a photo amplifier to make BW picture copies at home. I u…

I found this great idea on a video somewhere with many other life hacks. After doing it I decided to share my experience.

I've done this only with PET tops and caps and with glass bottles. I believe it's possible to use it with any bottle that can resist the heat, like maybe some metal bottle.

A good idea to use the rest of the PET bottle is to make a plant vase with a plate as I show here in this other instructable.

If you notice any misused word or strange phrase, please take a minute to tell me on a comment to help me improve my English.

Step 1: Materials and Tools

You will basically need

  • A PET bottle
  • A knife or other thing to cut the PET top
  • A heat source, like a heat gun, a small torch, a gas cooker or something else (a candle?)
  • A bottle that resists heat and/or fire

I don't have a heat gun, so I did it with my small torch and a little help of the gas cooker. Be careful with heat sources that have fire. We only need the hot air.

Step 2: Doing the Job

Well, the job is simple:

  • just put the top of the PET bottle over the top of the glass bottle
  • throw heat on the PET top part that needs to shrink until it hold the glass firmly


  • I'ts not a problem if you use a heat source that causes a flame on the plastic, just put out the fire as it happens
  • Be careful not to throw heat on the screw part or you can have problems to put the cap at the end
  • It's a good idea to wait the plastic and the glass to cool down completely before testing if it's firmly attached
  • If the test fails, just blow heat again
  • It's not a good idea to try to cool down the glass with water or any cold fluid. See what can happen in the picture with the green PET top

Again, you can do other things with the rest of the PET bottle and one of my favorite usages is shown in this other instructable of mine.

I hope you like it and if you do, please consider voting for this tutorial in the Plastic Contest. Just click on the top right orange flag "VOTE" to do this.

Thank you!

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    4 years ago

    neat trick! Please be careful when heating plastics though, the vapors can be toxic.

    DIY Hacks and How Tos

    Interesting. If only there was a way to easily move it from one bottle to another.


    Reply 5 years ago

    Just an idea: Shrink it onto a stick or something that has the diameter you need (covered with some oil/foil or something elso so you could remove it afterwards). Use some ranger band (rubber from bike tube) or similar to attach the sealing cap to glas/other bottles. As mentioned, that's just an idea ...


    Reply 5 years ago

    Great Pumuggel! I would say you don't even need this other stick, you can use the glass bottle itself. Even when it looks already tight it still gets off. I'll see if I can try just to use the rubber idea to be able to move between bottles.


    5 years ago

    You asked for a correction. In the 2nd paragraph you were talking about "use it with any bottle that can resist the head". Did you mean "resist the heat"? If so, sadly Auto-correct won't correct that kind of mistake. Which is why I have to proof read A LOT.


    Reply 5 years ago

    Thank you Joen! This is the second time I do this here, changing 'heat' to 'head' (the other was in another instructable). I guess my head is a little heated :) The other one I've noticed in a proof read, but this one passed :)