[javawizard]

> Argon [...] cost about $2 per liter each.

Uh, what?? No it doesn't.

I'm a hobbyist welder. When TIG welding you typically use 100% argon gas. I have a 60 cu ft cylinder hooked up to my welder right now; it costs $89 to refill at my local Airgas store.

That's approximately 5.2 cents per liter.

Here's a 40 cu ft tank of argon for sale on Amazon for $205: https://www.amazon.com/100-Argon-Welding-Tank-CGA/dp/B00I4Z6...

That's a new cylinder so most of the cost is the cylinder itself, but even then, that only comes out to 18.1 cents.

How on earth did TFA come up with $2/liter? Did they get liters and cubic feet mixed up while doing their research?

[Etheryte]

As with anything medical, the price of the item isn't just the item itself, it's purity plus that someone has verified and stamped off on it. I don't know much about argon, but for nitrous oxide, food grade is generally between 99% and 99.9% pure. If you want medical grade, the threshold is 99.99% pure or better depending on what you're doing. Those additional nines are what drive the price up, plus the fact that someone put their skin in the game and signed off on it with their name.

[DannyBee]

So Ultra high purity stamped argon (99.9999) is twice the price of industrial argon used for welding.

Food grade Argon is actually half the price of industrial argon.

See https://www.airgas.com/product/Gases/Argon/p/AR%20FG300 vs https://www.airgas.com/product/Gases/Argon/p/AR%20300 vs https://www.airgas.com/product/Gases/Argon/p/AR%20UHP300

[DannyBee]

In the case of Argon, it's both inert and non-toxic. The main danger is that it's heavier than air (so you can asphyxiate yourself if you try).

As such, "food" grade argon is actually less pure than industrial argon - food grade is 99.996 and industrial grade is 99.998

The practical difference is what contaminants exist - because argon is non-reactive, in food grade argon they are just trying to remove contaminants you don't want in food.

In industrial grade argon, mainly used for welding, almost any kind of impurity can cause issues, whether it would be "safe to eat" or not.

[buildsjets]

They may have been referring to the price of Argon in it’s cryogenic liquid state. A 160L liquid cylinder will expand to 4426 cu ft at STP. Source: I used to design cryogenic liquid cylinders for MVE. Here’s a manual for typical cylinder.

https://www.chem.purdue.edu/chemsafety/docs/equip/Manual_MVE...

[aredox]

I guess "medical-grade" xenon (for anesthesia) would be extremely more expensive (with warranties on purity from contaminants such as pump grease).

[DannyBee]

"Uh, what?? No it doesn't."

He works for Airgas, clearly :)

I'm with you on pricing - i pay about the same.

Actually, Airgas has research grade xenon at $132/standard liter. So much more than they are claiming in the article.