How to Heat Seal Foil Balloons

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As part of our series of articles discussing the options available to you for the tools you will need in creating some of our ideas, here at Potters Party Balloons, we thought we would discuss how to heat seal foil balloons.

Whilst large foil balloons intended for inflating with helium have a self-sealing valve, smaller foil / Mylar balloons do not have a valve and therefore require heat sealing after being inflated with air.

The options for heat sealing your foil balloons include using a Mylar sealer, a mini food-storage bag sealer or a set of hair straighteners.

We recommend using the Mylar heat sealer for the best results but will discuss all the options in this article. We have split the article into the relevant sections so you can simply jump to the bit your interested in if you so wish.

Inflating Your Balloon

Firstly you need to Inflate the foil balloon with a hand pump. It is not advisable to use an electric balloon pump for small foil balloons as you are likely to over-inflate and burst the seam. In fact, you have to be careful even with a hand-pump, because over-inflating is again quite possible.

Once you have balloon inflated, pinch the neck of the balloon closed between your fingers. There are two schools of thoughts regarding where to pinch the neck. You can pinch it nearest to the inflated part of the balloon or at the bottom of the tail.

Pinching the neck nearest to the inflated part of the balloon gives you a tidier result as you can seal the balloon and then cut-off the excess tail. However, pinching the neck closest to the tail allows you to make mistakes during sealing and even cut-off the seal and re-inflate to try again.

The second method is particularly useful, if there is a chance that you want to re-use the balloon in the future. To try to give a professional and clean look to your result, we would however suggest the first method!

Using a Mylar Heat Sealer

The Mylar heat sealers are easy and reasonably safe to use. They do not get warm until you have actually closed the jaws of the sealer.

Plug-in your Mylar heat sealer and select a low-setting. It’s better to have several attempts at sealing your balloon than to wreck it by melting it because the setting was too high. If the setting was too low, you can always adjust it and try again!

Selecting the setting will depend upon the quality of the balloon. As you can see from the attached video, the professionals suggest using a setting of 3 or 4, i.e. a medium setting.

Insert the neck of the balloon, below where you have pinched it, into the jaws of the Mylar heat sealer. Keeping the balloon pinched and your fingers away from the jaws, close the heat sealer until it clicks and hold it there for between 5 and 10 seconds and then open the jaws of the heat sealer.

Your balloon should be sealed. To be extra secure, you can seal it for a second time a couple of millimetres down from the first seal.

Using a Food Bag Sealer

As a cheaper alternative to the Mylar heat sealer, you can try to use a mini food bag sealer. It is a little more fiddly and you do not have control of the heat setting so the success rate is not guaranteed. But if you already have a food sealer or you need one for your food bags anyway then it is certainly worth a go.

Insert the balloon, just below where you have pinched it, between the two heating sheets of the food bag sealer. Press down the heating sheets together and hold for between 3 and 5 seconds to start the heat sealing process, then slowly slide the food bag sealer from one side to the other of the balloon neck.

Try to slide the sealer at a constant speed and ensure you give it enough time to seal each part of balloon neck. We did say it was a bit more fiddly!

How to Heat Seal foil balloons with a food bag sealer

We tried to find a picture example of heat sealing Mylar balloons using a food bag sealer, but failed miserably, and therefore the picture above shows a foil food bag being sealed. We believe the technique will work but as stated the success rate is not guaranteed!

Using Hair Straighteners

Well, why not let our tools be multi-functional. Most ladies (or girls) and probably a few men will have a set of hair straighteners in the house, so let’s use them to seal our small foil balloons. Unlike the food bag sealers, a decent set of hair straighteners (or flat hair irons as they are known in other parts of the world!) usually has a temperature setting so that you can control whether you will melt your balloon or not!

Turn on the hair straighteners and set them on the lowest setting but allow them to warm-up. Remember the irons on hair straighteners do get hot even when they are not closed together and therefore be careful not to touch the irons.

Place the balloon, just below where you have pinched it, between the iron plates of the hair straighteners. Close the hair straighteners and hold for between 5 and 10 seconds to complete the heat sealing process. Hair Straighteners have a wider heating area than the Mylar heat sealers so there should be no need to seal the balloon twice.

We have it on good authority, from other professional balloon decorators, that this technique does work!

Our Recommendation

Whilst using hair straighteners or food bag sealers could produce some decent results when heat sealing your small foil balloons, we at Potters Party Balloons would recommend using the Mylar heat sealer, if you can.

Small Foil BalloonsWe do feel that the Mylar heat sealer is more designed for purpose and is more likely to guarantee you a successfully heat sealed balloon.

For a review of the heat sealers available, please take a look at our 5 Best Heat Sealers post, here on this website.

If you have tried heat sealing small foil balloons with any of the techniques we have mentioned or have any questions, then please feel free to comment below or contact us directly via email or social media!

12 thoughts on “How to Heat Seal Foil Balloons”

  1. Hey there, thanks for sharing this post. I like how you have included all the information and tips for heat sealing foil balloons. This is something I rarely do myself so this post has helped me a lot to learn how to do it properly.

    The video is also very helpful, and those posts you’ve written previously just compliments the whole topic here. Much appreciated! I’m sure other readers will feel the same as me so thanks once again!

    One question though. Can you use impulse heat sealer for other purposes too or is it just for sealing foil balloons? Thanks in advance!

  2. I’ve been avoiding buying balloons for years simply because of the waste. I hate spending so much on something that is only going to last a day or so and then gets thrown away. This may be a great resource for reusing balloons. It’s something I simply gave up on because they’re so bad for the environment. 

    • I understand your comments!  There are however many types of balloons that will last a lot longer than just a few days! We all must do our bit for the environment and be careful what we throw away etc. But a party and a celebration is just not the same without balloons!

  3. Hello there, thank you so much for sharing this. this is a very awesome piece and a very detailed one. I’m really happy I came across this.  Reading about this article how to heat seal foil balloons sounds really interesting. Well I haven’t heard about this before but going through this article was indeed an eye opener for me. This article contains valuable information one needs to be aware of. I enjoyed reading about this article 

  4. There’s  a lot of things that we can do at the comfort of our homes without paying a dime for them and we can always make money from these services if we render it to people. It is thoughtful of you to share this, heating and sealing foil balloons will be nice an dthia will serve as guidelines.

    • Your so right!  there are many things that we pay for that we could simply do ourselves.  Washing our car is a classic example! I think covid and lockdown has changed many of our perspectives! Hopefully our article in how to heat seal balloons will have helped some people in saving a few pennies in these hard times, but still allowed them to have fun!

  5. Hi there! Great article! Before coming across this I never heard how to hot seal foil balloons! Thank Goodness I stumbled on this because I do know, this was very helpful to me to be honest and I had fun reading this! Keep up the good work! I will definitely share this with my friends. Warm regards


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