3 ms·
Latex balloons deflate due to helium permeating the latex. IIRC this is proportional to the difference in pressure between the inside and outside of the balloon
by Kadin 8y ago
Latex balloons deflate due to helium permeating the latex. IIRC this is proportional to the difference in pressure between the inside and outside of the balloon. (Because the rate is proportional to the difference in pressure.)
The balloon isn't going to deflate completely; eventually the pressure on the inside and outside will equilibrate. The balloon doesn't return to its original pre-inflated size because, I suspect, of some amount of irreversible deformation of the rubber as it stretches when inflated.
But anyway, balloon helium is quite pure, it's typically "Class 4" or "four nines" so 99.99% pure. At the local gas supply place, balloon grade and the stuff used for welding shielding gas are the same thing. While a lower purity might be fine for balloons, it presumably isn't worth it to them to either dilute it with cheaper gas or maintain separate product lines.
- dreamcompiler 8y agoWelder here. I don't buy helium for welding any more because it's too expensive; most welders use argon nowadays. But in any case the whole point of using inert gases in welding is to keep oxygen away from the hot metal. If welding-grade helium tanks contained any significant amount of oxygen they would defeat the whole purpose. And yes, for filling balloons, you just buy a tank of welding helium and screw a special balloon regulator onto the outlet port. The gas is identical. Makes you talk in a squeaky-high voice if you breathe a little of it; kills you dead if you breathe a lot of it. (Edit: I know somebody is going to ask why it kills you. Helium is not toxic, but it suffocates you if you breathe a lot of it without a break for -- you know -- real air.)
- somebodythere 8y agoAnd it doesn't trigger the asphyxiation reflex that inhaling carbon dioxide does.