HillBilly Hot Tub





Introduction: HillBilly Hot Tub

Here in the UK it's been a great summer and I thought it would be good to relax at the end of the day in a nice hot tub. Trouble is they are quite expensive to buy and run and you need power and chemicals and really how many times would you use one. So I decided to build a low cost hot tub which can be run off grid and can be used quick and cheaply to have some fun. 

Step 1: Materials

Knodd 40L bin with lid from your favourite Swedish bin emporium. £15 25 m 10mm micro bore central heating pipe from any plumbers merchants. £ 40 Kids paddling pool - I got a 1.9 m pool from Argos at the end of the season for £30 Aquarium 8mm tubing for pumping the water round your coil. 12v pond or bilge pump to circulate water. 12v power source - a car battery is ideal .

Step 2: Construction

The beauty of this is that it is so easy to make. We only need to construct our heat exchanger inside the metal bin in order to get tubbing! If you go with the Knodd bin you will see that it is tapered. This allows us to use it as a nice former for our heat exchanger. Start by drilling a hole in the side of the bin and insert the end of the coil from outside to inside the bin. Then start turning the bin smoothing the coil tight against the outside of the bin. After a while you will have a lovely shiny heating coil.

Step 3: Get Ready to Soak

Now you have your lovely coil you need to get it inside your bin. Since it is tapered you can take your coil and slide it inside the bin with one end poking out of the hole that we drilled to start. The top end you need to drill another hole and poke the other end of the coil out. You now have a cool portable hot tub heat exchanger. Now with a couple of flexible plastic tubes on the ends of your pipe you are ready to fire up your hot tub.

Step 4: Fire in the Hole

Now we are ready to crank up your hot tub. Fill up your hot tub with a hose - the one I had was around 700 litres and took a couple of hours. Get your pump and put it in the pool, connect the outlet of the pump to the bottom pipe from your bin - this is the hottest part of the burner. The outlet just flows back into the pool via your return tube. Careful it could be hot ! Get a nice hot fire going - your pool will heat up in around 4 hours if you keep your fire hot . Once it is up to temperature (I like 40c) you can damp the fire down with the lid supplied .

Step 5: Find Your Perfect Spot

So the benefit of this tub is it is portable - you can put it anywhere you have some water and a flat space - I have the perfect spot under my cherry tree. You can see the pool and pump fits inside the bin so its easy to transport. Enjoy with your friends our your favourite drink - mine is an Innis and Gunn :-) Have fun !



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    25 Discussions

    Question, just looking at those pumps, did you use a fuse between the pump and the battery?

    Wow! might try this modification on what we did. For my birthdays I like to go camping but I also love our Japanese bath so for a special birthday we did something like this but for heat we used an old Zoti water heater for use on propane camp stoves similar to this :


    by recycling the water through it and supplemented it with pots of water over the fire. Your way though you don't need to use a lot of propane so I like it better (although copper tubing is way pricey now). Either way though it was the best soak and we covered it with pool cover cut to fit and were able to use it again the next day (just wash first before you go in as with Japanese baths)

    I mean i know that my money value is 2• what yours is but it would make it easyer

    Nice but, could you convert in ( ) american money value?

    Try a homemade it reflector above the tub. line the underside of a garden parasol etc with reflective aluminized snack packets, Dorreetos are among the best. They are much more durable than space blankets. It DOESN'T need to be in contact. I promise you will be amazed. john


    4 years ago

    Great idea many thanks

    Love photo of the coiling process and your little dog looking at the camera. Too cute :^ D

    1 reply

    Great Idea, now for a 'mod'! If you were to cut out most of the bottom of the bin, leaving say a 1" rim inside, you could put a stout mesh inside. Put the bin on a coupla bricks. Then as your fire fuel burnt to ash, the ash'd fall out the bottom making yr unit self cleaning!

    great idea! Now a little 'mod' for you! If you cut the bottom out of the bin and put some stout mesh in there, you can stand yr bin on a coupla bricks and as the fire burns, the ash'll fall out the bottom...making it self cleaning!

    this is a awesome. we were without electricity for 10 days year before last and my husband and I took ice cold showers. gonna make one of these for emergencies as well!

    this is a awesome. we were without electricity for 10 days year before last and my husband and I took ice cold showers. gonna make one of these for emergencies as well!

    In the UK we sometimes like the off grid Hillbilly lifestyle :-) - but the heating coil is the same design as a Hillbilly Moonshine still.

    you have hillbillies in yhe UK?

    Cool idea and I too love innis and gunn my personal favorite is the rum cask.

    1 reply

    Thanks ! Nothing better than the rum cask - very smooth and just right for soaking your cares away :-)

    You could use this on any pond or paddling pool, maybe even stoke a small fire to stop a fish-pond freezing in winter.