Have you ever needed to freeze a water pipe to do a quick plumbing job without shutting off all the water? It’s actually a fairly common practice for contractors, except they use a rather expensive tool to do it. As it turns out, there’s actually a fairly cheap and easy DIY solution you can do with minimal supplies or experience.
[Go Repairs] shows us that all you need is some pipe insulation (or a large sponge), a plastic bag, two zip-ties, and a air duster can. Wrap the insulation and plastic bag around the pipe, and zip-tie it in place. Holding the air duster can upside down, release the majority of the contents into the insulation. Congratulations, you’ve just frozen your pipe.
It works by exploiting the properties of a compressed gas — in this case tetrafluoroethane — the “air” in the air duster.
When this gas is under pressure it exists as both a liquid and a gas in the can. When you spray the can normally, you’re just getting the gas out — but if you hold the can upside down, the liquid comes out instead. Because liquid tetrafluoroethane can’t exist at atmospheric pressure as a liquid, it boils instantly as it leaves the can. This causes an extreme temperature drop in the surroundings due to the endothermic reaction occurring.
For a complete explanation, check out the video below.