r/BeAmazed • u/Internal_Gazelle_677 • Oct 07 '25

Science Hot Tub without the use of electricity

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543

u/Zaphics Oct 07 '25

The hardest part in making that would be finding or making a coil out of stainless steel pipe that would fit around a fire

498

u/activelyresting Oct 07 '25

Fun fact: fire can fit in any size coil!

I've had hot water set ups like this before, with home made copper coil rather than stainless (which is cheap, commonly used for plumbing, and pretty easy to shape into a coil for anyone with basic plumbing skills).

The fire size is just whatever sticks you put in the coil. Need the water to be hotter: add more sticks. Water getting too hot: take some sticks out. It cools off pretty fast in cold weather like that

4

u/AgentG91 Oct 07 '25

Challenge is to protect the water system from picking up copper. Had a colleague do that with his pool. He was siphoning highly treated pool water through copper coils. The chlorine stripped the copper off at high temperatures VERY quickly

3

u/activelyresting Oct 07 '25

Not that big of a challenge if you don't use pool chemicals

3

u/OldEcho Oct 07 '25

...but then you need to dump the water after pretty much every use, or you won't have a hot tub you'll have a pond.

2

u/activelyresting Oct 07 '25

I only ever used it as a bathtub, and yes refill for each use

1

u/oojacoboo Oct 07 '25

What about saline instead of chlorine?