Sciencemadness Discussion Board

Storage under inert atmosphere in an argon-filled tub?

math - 3-6-2025 at 07:52

Hello, I'd like to store my rust-prone and oxidizing-prone collection of elements and essential oils in an argon-filled tub.

Do you think argon's density will be enough to keep it from escaping the tub and form a permanent layer on top of my items which will stay even if from time to time I pick some up? Or would I need to top it up with argon each time?

Is polypropylene relatively impermeable to argon or would it diffuse thru it?
The tub's lid is just a normal lid, it is not gas or liquid-proof.

Is there some sort of indicator I'd leave, to indicate there is argon in the bottom 2/3 of the tub, like the floating tinfoil ship as seen is SF6 videos? I know that SF6 is a lot denser, but just wondering if there could be something similar I'd use as visual indicator.

Thank you

[Edited on 3-6-2025 by math]

bnull - 4-6-2025 at 01:03

You know that, if the elements and the essential oils are stored in inappropriate flasks, the oils will eventually diffuse into the element flasks and possibly react with them, right?

You don't need to know if argon is still there at the bottom, but if there's oxygen there as well. You can buy oxygen indicators for book storage (OxyEye is an example). They change color when oxygen goes above 0.05 or 0.5% (I forgot which one).

An alternative is to buy hermetically sealed flasks (I think jam jars with silicon gaskets will do), fill each with argon, carefully store the element or essential oil flask (each one in a jar) so as not to disturb the gas, and top with argon. Close the jar. This way you will only disturb the gas in the flask you open, not the whole tub.

Using a non leak proof box for storage is a bad idea to begin with, but it is none of my business if you do.

math - 5-6-2025 at 14:20

Quote: Originally posted by bnull  
You know that, if the elements and the essential oils are stored in inappropriate flasks, the oils will eventually diffuse into the element flasks and possibly react with them, right?

You don't need to know if argon is still there at the bottom, but if there's oxygen there as well. You can buy oxygen indicators for book storage (OxyEye is an example). They change color when oxygen goes above 0.05 or 0.5% (I forgot which one).

An alternative is to buy hermetically sealed flasks (I think jam jars with silicon gaskets will do), fill each with argon, carefully store the element or essential oil flask (each one in a jar) so as not to disturb the gas, and top with argon. Close the jar. This way you will only disturb the gas in the flask you open, not the whole tub.

Using a non leak proof box for storage is a bad idea to begin with, but it is none of my business if you do.


Thanks for the info. I will get some oxygen indicators as you suggested. About using a non leak proof box, it was more about the convenience of being able to also lay papers, antiques etc flat in it, visualizing the tub's argon as if it was water in a container, so that aside from splashing caused by opening the lid and putting hands in it, the higher density would keep it inside.
Maybe that was too naive of me, since I guess the density difference compared to air is not enough to have it settle in the tub.

BromicAcid - 5-6-2025 at 16:02

The tub idea sounds fun in practice but probably will not be too practical. Gasses by their nature will expand to fill whatever container you put them in, When it's sealed that's fine but when you open it, there will be eddies, mixing, diffusion, oxygen/air will diffuse into the argon and vice versa. Your argon will become more and more contaminated and will make up less of the total volume. Again, love the idea but don't think it's going to be as useful as you envision.

unionised - 6-6-2025 at 04:55

"Do you think argon's density will be enough to keep it from escaping the tub "
No.
Gases mix.

Hydrogen sulphide is rather denser than air.
Noses are generally higher up than hindquarters.
Farts still stink.

Also gases like oxygen can diffuse through plastics so you might need a continuous purge of argon.

Metals or glass are a whole lot less permeable.

Dr.Bob - 6-6-2025 at 12:31

yes, Even argon filled glass slowly leaks. Glass and metal will work well, plastic leaks gases via permeation through it. Only a few plastics are low permeable. That is why soda goes flat in plastic bottles quick compared to aluminum cans.