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helium gas holding material? Answered

can one suggest me light weight envelope materials to hold helium gas with 70 to 100 grams per square metre

7 Replies

Vyger (author)2017-02-22

Mythbusters made one out of lead, a balloon that is. But they also used helium to fill it. And it was pretty big.They were a little surprised they actually managed to do it. If they could make an envelope out of lead foil and have it float I would guess you can make one out of aluminum foil. It would be very delicate work.

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Downunder35m (author)2017-02-22

The airships use a double walled system which contain several layers each....
As said by the others already on a smaller scale only metallised foils will hold helium for a suffient time.
Problem with helium is the molecule size and special properties of this gas - it goeas through everything if not thick enough, made from glass or thick metal.
Mylar is basically a stretched polyethylene foil.
If you ever ripped a plastic bag you might have noticed that first it stretches quite easy, than it suddenly stops (after that it breaks).
Same is done to create Mylar.

Enough tech talk...
Since you said you can accept quite a weight per m² I think you should also specify the use.
Let's say it is for something the size of a wether balloon.
Then space blankets that you heat weld together can be an option.
If you need to carry some serious weight like one or 2 kg you need a thicker mylar foil that is metallised on at least one side.
Last but not least we would need to know your skillset as welding foils to make them gas tight is not really that easy....

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steveastrouk (author)2017-02-22

I think that is the material the pros use. I mean, professional party balloon mongers.

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In contrast, if you get your party balloons from those amateurish, unprofessional, balloon mongers, then you don't know what you're gonna get.


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Oops! I forgot to include the link, from a page titled, "6 ways to write on a balloon"


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Jack A Lopez (author)2017-02-22

I think the shiny, metallic, balloons sold at the florist, or party store, those are made of aluminized PET.

The Wikipedia article titled, "Toy balloon", calls this kind of balloon, a "foil balloon",


although I have heard them called, "mylar balloon", where the word "mylar" is a genericized trademark. It used to be called, "Mylar(r)", capitalized as a proper noun, and with a little (r) in a circle following it, because it was a registered trademark of Dupont, the company who invented it.

Also the Wikipedia article for, "Metallised film", seems to mostly be an article about aluminized PET.


Anyway, I am not sure what it masses (weighs) per square meter... Well, actually, I have a piece of it here, that I know what it's area is. I guess just need to put it on a scale and mass (weigh) it.

The artifact I am speaking of is this mylar, emergency space blanket, thing. There a discussion about mylar, Mylar(r), and other metallised plastic film, on the Answers forum just the other day, here,


Regarding my space blanket, it is a rectangle 1.3 m by 2.1 m, according to the text printed on the box. I put this folded-up blanked on my scale, and massed it at 45.7 +or- 0.5 g. So that gives a mass/area ratio:

(45.7 g)/(1.3m*2.1m) = (45.7 g)/(2.73 m^2) = 16.73 = 17 g/m^2

So it looks like pretty light stuff. It seems to be pretty strong too, compared to similar things, like those plastic shopping bags made from LDPE or HDPE.

I'll attach here the same picture of my shiny space blanket I attached to that other discussion.

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