Camping Hot Tub

Intro: Camping Hot Tub

Sitting around the camp fire at a lake has left us too hot on one side and freezing on the other. 
Drunken idea - A hot tub would keep us warm all over. 
It would also get the girls in thier bikinis!
How will a 10x10x2ft body of water be heated and kept hot? 

Don't forget to comment, rate and share! :D

Caution!

This intsructable is how to build a Camping Hot Tub and is for entertainment purposes only. 
Safetey first!!! It involves power tools, fire, electricity and water.  Recreation can be very dangerous.   
I am in no way liable for anything you do, damage to vehicles or equipment,
loss of life, accidents that may occur, fines incurred, acts of god, etc.
Leave it the way or better than you found it! Clean-up and don't start a forest fire!

DO NOT CUT DOWN TREES!

Goals:

Transportable hot-tub equipment.

Tools:
Chainsaw
Shovel
car/truck or Generator

Materials:

Tarp 20x20
copper coil 5/8" OD. (outside diameter) @ 100 ft.
hose 5/8" ID. (inside diameter)
hose clamps, Get more than you need!
Washers
Power Inverter
pump 1/12 hp utility continuous operation
Large pond pump
large hose
Rocks (should be on the beach or in the river)
strong metal baskets (look around at thrift stores)

STEP 1: Location

Find a really awesome camping spot. Either near a lake or river preferrably within 100 ft or less. Send the minions out to gather wood for the fire. The more the better.  We burn a utility trailer load every 3 hours.

The tub needs to be close so it can be filled and refilled as needed.

STEP 2: Frame

Find some beach logs and send the minions out to gather wood for the fire.

Caution! Chainsaws are not toys!

Cut the logs to equal lengths so they can be stacked, notching the ends.
Flaten an area so the logs will not roll out of place.
This will begin to look like a log house "foundation",
if there are other groups around - prepare to answer questions.
This frame will need to be about 2- 3 ft tall.
Get a helper to build a fire.  Get another helper to move those neatly cut logs with you.

Tip! placing a path of lighter logs on the ground makes rolling the big logs easy!

STEP 3: Liner

Place the center of the tarp in the middle of the frame.
The water will spread the tarp to the outside and fill the holes.

Tip! Place a decent sized rock in the middle to hold it in place while filling!

STEP 4: Pump Setup

To fill this large hot tub, connect the Large pond pump to the large hose and  power inverter or generator .

Caution! If the power inverter is connected to a vehicle and it is the only one there this is a bad idea!

Place the large pump in the water with a filter or it could and will suck up sand. If this happens the pump will break.
Fill the pool with water.

Tip! Use the smallest vehicle as it will be the easiest to jump and restart.

STEP 5: Stone Boiling

Caution! Rocks that are hot will burn!

Place rocks in baskets in the fire the minions have prepared. After about 15 minutes the rocks should be hot enough to heat some water.

Caution! Do not place the baskets on the tarp, it will melt!

Use an insulator like large branches to keep the baskets off the tarp. Once there is a signifigant amount of water in the pool,
place the baskets in the water.
Exchange them in intervals of about 15 minutes. 4 baskets of rocks keeps everything moving ahead.

STEP 6: The Small Pump

Now the pool is full and getting warm from the stone boiling. Disconnect the power inverter or generator from the large pond pump.
Prime the inlet hose by placing it in the pool. Connect it to the appropriate side of the pump and test to ensure it will pump water.
Connect another hose to the first 50' copper coil with a hose clamp so that there is the proper connection for the pump on the other end.
connect the two copper coils with a section of hose and two hose clamps. Then connect the second copper coil to another section of hose that
leads to the pool. Weight the out-to-pump end of the hose in the pool so it always is free of obstruction.

Caution! The copper coil will melt if water does not flow through it whilst in the fire.

Prime the hose that goes to the pump, turn it on and connect it to the hose that goes to the copper coil.
Things should be wet but functional. Check the in-to-pool end of the hose to make sure water is flowing freely. Troubleshoot if not.
carefully place the copper coil in the fire ensuring ALL rubber connections are at least 1 ft. from any heat, preferrably protected.

STEP 7: DONE~!

Things should be warm by now, so go get in and keep the fire and the pump going! Maybe make a new friend! Enjoy the warm water of labour.

This was my first instructable. I hope it was buildable! XD

Comments

[blomeclown]

Great instructable although I wouldn't try it. Not because it's a bad idea or dangerous or destructive to the environment (all comments that have already been made) but because my idea of roughing it while camping is when the pizza delivery is late to a 40 foot Airstream trailer.
This is aimed at the commenters who post the "I would have done.........." or "You should have..........." comments, NOT at the ones who post the "I made one of these but I........" comments. You know who you are and you know what the difference is. Player2756 had an idea, worked on it and did it. If you think you have a better way, post a frakkin instructable. Just give Player2756 some credit even if you disagree with his methods.
There were several comments made about the extra work that may have been needed to make this tub the way it was made. So what?? I can't think of a better way to spend time at a lake than to work your butt off doing something and then relaxing with a cold beer and some cuties in a hot tub. Kudos, Player.

[Foehammer358]

This man gets it.

[OogieMustBoogie]

Amen.

[hogey74]

OK this is awesome. I am promoting you to honorary Australian. You just need to let off some illegal fireworks or develop a new type of spud gun and you can be a full citizen.

[player2756]

Thanks mate!

[adodds1]

hahaha 'mate' - gotchya

[hogey74]

:-)

... and 3 years on, this thing still rocks!

[yerdadh8sme]

You sir are my freaking hero! That is AMAZING! Now if I can convince my fellow campers to help me do this we will be in business! I literally just set up an account here so that I could thank you for this idea.

[player2756]

Its lots of work but is fun at the end of the day!

[spaztec]

I applaud the pot-of-fire. It made my day.

[raygris]

Hot rocks can work fine. You do have to choose your rocks (smooth, hard, no cracks) This method has been used for centurys in sweat lodges.
Anouther method:
A friend of mine used his truck as the pump and heat source for a portable carnival "dunk tank". The tank was an old wood hot tub.
He diverted the radiator hoses to a scrap radiator that was submerged in the tub. Quick and easy. One person setup. 2- 2.5 hrs start to tubbing.
.

[velojym]

I like this. I've considered toting around a 6 seat inflatable hot tub, with the heater/pump and stuff, and that's still on top of my list, but I really do like this idea, and may well try it in the right conditions. Folks who say nay for the sake of saying "nay".... I don't even bother listening to them. :)

[pyroparker]

What flow rate would you recommend for circulating the water through the copper coil?

[player2756]

I don't know the flow rate, however 1/12th hp sump pump and 50ft of 5/8"o.d. Copper combo works well.

[rvstealsanddeals]

Funny and Fun! I recently saw something like this to travel in an RV. It's basically a mini hot tub that inflates with a built in heater. Looked cool.

[klarsen-crisp]

has anybody ever used a coil on top of a propane camp stove?

[MRCrabtree]

I didn't for this purpose, but when I was camping in the mountains I did fashion a hot water shower using a propane burner heating a pot of water and submerged my copper coil in that. Much better heat distribution, however, with the shower set up i couldn't recirculate my water and need it to have more efficiency in heating.

Problem was that it worked too well I got my shower way to hot and heat adjustments to an entire stock pot of hot water are not quick.

[OurPantheons]

Dudes! I so have to try this. Thanks for the awesome idea and instructable.

[timbit1985]

Using a small rocket-stove type setup with heat exchangers in the combustion chamber would be more efficient :)

[rsavenkoff]

I've been working on a very similar project, only using an 8' above ground pool (650 gal) as the camping hot tub. They're relatively cheap, easy to transport, and quick to set up. My first attempt to heat it was using 50' of 1/2" dia coil placed directly in the fire, as is shown here, and I ran water through it using a 1/6 hp submersible pump run off of an inverter connected to my car. It took a loooooong time to heat, probably 7 hours, and we went through a tremendous amount of wood. It was fun, but not practical anywhere that you'd need to pay for wood. $$$!! We were lucky that there was an abundance due to a landslide in the area a few years before. My next attempt was using a homemade woodgas stove with a heat exchanger just above the combustion zone. My goal is to heat the tub using pellets, which are cheap and easy to deal with. Details of that build are irrelevant, as it worked great in a batch type burn, but would fill with charcoal for the longer burns required to heat this much water, and turned out to be too annoying to deal with. Refilling it was a mess and would drastically effect the flame, very inconsistent temperatures resulted, and intermittent big black clouds of smokey unburnt fuel would be lost out the chimney. My third attempt was using a rocket stove with a heat exchanger on top. With a 6" diameter burn chamber, 4 x 50'x 1/4" diameter copper coils in the heat exchanger, everything veeeeery well insulated, the system converts about 40% of the potential energy of the pellets into water heat in the pool. I think it outputs a real water heating value of about 23,000 Btu/hr into the pool. Which i think is pretty decent for a portable homebuilt system. It resulted in a 9 hr heat time, and only costs $1/hr to run, and produces almost no smoke so you know you're not wasting any of your fuel. 9 hrs is still waaaay too long though, that's a whole wasted day. (A side note: there is massive restriction in 1/4" copper tubes, even having 4 plumbed in parallel caused a big reduction in flow. I wouldn't recommend going this small.) The rocket stove was well behaved though, and the concept seems to work well. To get the heat up time down to a passable 2-3 hr range, I think you'd need a rocket stove with about 400% of the output of my 6" diameter system. I haven't built or testing the next prototype yet, but I'm thinking it should be a rocket stove with a 12" diameter burn chamber, which according to simple math should get me to 400% increased output. I haven't figured out how to build this yet, so can't offer any advice there, but according to my tests, and the math, this seems to be the size that would be practical for this application. I hope someone out there find this info handy, it's taken months of meddling!