# Makeshift Riverside Hot Tub???



## deepsouthpaddler

Hey all you McGyvers, welders, raft gear builders, etc... 

Anybody got any thoughts on building a makeshift riverside hot tub on the cheap? I've done some research, but I'm wondering if anyone has any experience here.

I've got an idea for a large makeshift hot tub. I want it to be big. I had a rough concept of building a square box out of trees (think 3 ft high log cabin type logs... maybe 10'X15' or something like that). Would maybe use a rubber pond liner to make a water holding container that sits on the ground and over the sides of the trees. I found a bunch of videos on you tube of people who made steel drum wood burning water heaters... build a fire in the bottom of the drum and have copper tubing coilded in the drum to heat up the water. Some folks used natural convection to push water through... better solution would probably be a water pump to circulate water through the tubes. I'm thinking for a big tub, you probably need 2 or more of these water heaters.

So my half baked thought was... lay out the challenge to mountainbuzz. Can we collectively design, source, and build a McGyver hot tub for Bailey Fest next year? I'm looking for ideas on how to make this type of set up work. I'm also looking to see if anyone out there who has welding experience, any materials (steel drum, copper tubing), or similar expertise to help build this thing. 

My loose thought was that amongst the folks here, we collectively probably have enough equipment to put this thing together. I had an idealistic thought that if everyone who was interesting in putting something like this together chipped in a little, that we could get a kick ass hot tub, fill it with river water, crank it up, and dismantle it when the fest is done, all while doing it on the cheap with mostly stuff people already have and are willing to donate (time, materials etc).

There is a log house lumber yard just up the hill from the fest site I could likely get some nice logs from. 

Crazy or doable? Anyone interested in something like this?


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## kayakfreakus

We had a very good attempt on the middle fork, but our system would have needed a layover day to get to hot tub temps. It was a blow up pool, filled, then used a drill pump to run the water through a fire pan. Was a lot of fun and we were convinced in theory it would work, but we ran out of time. So bigger fire or bigger drill pump? Since yours is more permanent and does not need to be packed up and on a raft the next day you should be able to pull it off...


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## Avatard

Was that cave camp? Why not just set it up at hospital bar?


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## kayakfreakus

Avatard said:


> Was that cave camp? Why not just set it up at hospital bar?


Yeah I mixed trips up, the hot tub was Gates of Lodore...


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## oarframe

Interesting concept - here are some potential solutions

Portable Hot Tubs | Bullfrog Spas Blog

i like the "ideal" tub, could combine a soak with dinner prep


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## deepsouthpaddler

Awesome set up freakus. My first thought was to do something basic with a firepan, but when I saw the steel drum set up, I thought that would get extra heat. Nice use of the drill pump! I haven't used one, but love the concept.

At the bailey fest camp site, I have electrical power, so running a small pump or two won't be an issue.

Also, my plan was that I would set the tub up early friday AM, crank up the heat and hopefully get it ready for friday PM or worst case, sat PM. 

Got a laugh out of the makeshift tubs on teh bullfrog page too. I guess what I was thinking was probably more in line with the college kids / tarp / box set up...


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## Dave Frank

I got close with a small kiddie pool and a 12v bilge pump. I used a 1/4 barrel on the blaster as a heat exchanger, but by midnight it had only reached the mid eighties for temps. 

With power and the superman showdown pump it should be preset easy. It's just a question of how gig you can go. 

Some 55 gallon drums with heat tubes in the bottom like a Snorkel wood fired tub would be pretty powerful. They could have wood legs and sit in the pool, or be poolside with a pump to circulate.


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## Rojo

*Hot tub by Instructables*

Efficient option, pending site, would be to dig a pit tub and seal with a pond liner sheet.

Interesting step-by-step for log frame tub.
Camping Hot Tub

Excellent heat source could be the old army issue M67 immersion heater, which uses a drip fuel fire chamber that is submerged into a metal trash can, then re-ciculate/pump into hot tub as needed. Use caution regarding the drip fuel control.








Immersion Heater, Unused, Complete


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## deepsouthpaddler

Rojo, that camping hot tub is exactly what I was thinking of... except bigger. Great link.

Dave, I wouldn't use the supermax showdown pump... to much flow, and they are expensive and break too easily. I do have some smaller pumps that would work perfect for this set though. 

I wonder how well a tarp would hold up. Seems like it would get pinholes really easily? Might be a good cheap solution though. 

I guess the main thing is getting the copper tubing and fire pan / steel drum heaters figured out, as well as the logs and the tarp for the tub. I have two pumps I could use to circulate water.


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## kengore

Friends and I have made several portable hot tubs over the years. Anything from a low volume two person to a 20 seater. Here is what I can share from our experiance...

1. It takes a great deal of heat to bring water to tub temp. You need massive heat output and a long time. Our best versions required at least 6 hours to heat up. If you want to use it in less time go with a sauna. A sauna is MUCH less work, uses about 1/50 as much fuel and heats up in as little as 30 minutes.

2. The lower the volume the less water to heat, reduce the height of the water to a minimum and be thinking a tight 4 person tub not the 20 seater. (We built a 20 seater once, it took over 14 hours and about 1 1/2 cords of wood! Once we got it going it would coast along with just a little wood now and then.)

3. Almost any water tight structure can be made into a hot tub. Kiddie pools, 6 mil. plastic tarp and a ring of hay bales, foam sleeping pads wrapped into a ring and lined with a light plastic painters tarp. Continous liners work well, joints of any kind did not.

4. We had the best results from submersible type heaters. We found local wood or 20 lbs propane cans to be the best fuel sources. External heat exchangers were not as efficient and required a pump for circulation. A submersable wood heater can be as simple as a 35 gallon drum weighted down with rocks. An easy propane heater can be made from a U shaped piece of iron pipe and a propane weed eater like this..
Flame Weed Dragon Torch Kit — 100,000 BTU | Torch Kits| Northern Tool + Equipment}
Submerge the pipe with both ends above water and attach the burner nozzle to one end.

Note: things below the water line do not get too hot for short skin contact, however, things above the water line can get red hot. Don't let the heater have direct contact with the liner, used some kind of standoff for at least a 3/4" seperation.

5. Smaller is better, go for the lowest seating capacity and the minimum water volume to reduce fuel cost and heating time. Insulating the bottom by placing foam sleeping pads below the liner worked well, insulating the top (other than a wind cover) or sides did not have a big effect.. You can make up for poor insulation with more heat, fuel might be more portable than insulation. Increase your heater efficiancy by designing it to have a maximim wet surface. The larger the under water surface area the better, avoid large above water surfaces that just waste heat. 

Wood fired heaters benifit from a flue and a fresh air vent, adding small fan to the fresh air vent can significantly increase heat output. Think of the difference between a cozy camp fire and a forge, HUGE amounts of heat can be created with a forced air wood fire. On the other hand, the propane heaters are super simple, just a nozzle and a pipe. As a result they are the most portable and require the least attention.

6. Hot water gets really skanky after a day, use some bromide tablets to go for a few days.


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## deepsouthpaddler

Thanks for the tips Ken. I'm gunning for a big one, so I will have to balance heat output to be able to make the larger water volume hot.


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## kengore

Our big tub was about 10' in diameter, filled to about 26" of water( this is chin height for a sitting adult. It was made of 8 pieces of 4' X 2''-6" X 1/2" plywood panels reinforced with 2X4 at the edges and lined with a large blue poly tarp. A series of ropes provided tension. It seats around 20 adults if you really like each other..

The heater was made from a 55 gallon drum on a 3/4" plywood base cut to 6" over the drum diameter. Cage of wire fencing was placed around the drum and filled with 6" cobble. This provides enough ballast to prevent the drum from floating and acts as a heat shield for bathers. The top of the drum was cut down to about 8" above the water line and fitted with a door, 6" flue with damper and a 2" dia. intake vent. The intake vent was made from a 30" length of black iron pipe with an 90 degree elbow at the top. The length of the pipe was designed to provide fresh air at the lowest part of the drum, the elbow prevents it from falling in. A 12 volts blower was attached to the intake. Set the stove at one edge of the tub so you don't need to get wet while feeding it.

This set up was filled with lake water (at about 43 degrees F) via a gasoline pump and hose. Heated to 106 degrees F in about 14 hours of constant fire, used about 1 1/2 cords of pine wood over a 5 day period. Most of the wood was burned in the first 14 hours.


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## abron

My boss from the rafting company had the best portable hottub/backwoods bathtub i've ever seen. its a simple, tried and true... but its all heavy stuff.and you need to have a welding connection to fabricate a snorkel stove unless you want to purchase one...

This would be perfect for Baileyfest, or any car camping river trips..... all you need is a trailer for the equipment, firewood, and water.. 

its a Snorkel stove in a Large horse trough.... the one I sat in at a guide rendezvous here in NM was pretty awesome. It fit 10+ people,(depending on the size of the trough) and was plenty hot...but it was also capable of getting dangerously hot, If it heated for too long,and the stove was not shielded so one could burn the shit out of themselves if they were rough housing, or slipped or leaned over to catch the floating bottle of whiskey.... in other words perfectly safe fun for a bunch of inebriated shrooming rafters.... 
(IIRC no one was hurt by the tub, only by the sight of the boss man dropping trou and displacing a lot of water when he got in ....) 
a quick google search had lots of pics and ideas...

Here' s one of many pics i found for a concept of what it looks like. 

Snorkel stove for wood-fired hot tub



















btw, i really hope to make it up for baileyfest next year. I was planning for it this year, but it didnt work financially... its been one of those summers...


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## kengore

You could modify a 20mm ammo box to look a lot like that snorkle stove...

It looks like they are using a simple interior plate as a baffle for the fresh air intake. You could cut a hole in the standard lid for a flue and slice it in half for a hinged door. I like the simplicity of the sliding door as an air vent.

You could get some of the telescoping stove pipe sold here, I think it would fit inside the ammo can.
Cabela's Sheepherder's Stove Pipe, Outfitter Tents, Stoves, & Accessories, Hunting Outfitter's Camp, Hunting : Cabela's


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## Dave Frank

Those Snorkel fire boxes have tubes at the bottom that act as both andirons and allow water to circulate where the coals are resting. If someone had the welding skills to add those to a 55 gallon drum, fitted with a top with a lid and a chimney and a feeder door, it would heat huge.

I love the hay bale idea, and by using a lower layer to shrink the diameter at the foot well, it would allow a deeper pool while somewhat limiting the total volume of water.

Ian the showdown pump would only be utilized for the initial filling; shouldn't tax it any more than running the pump. Didn't you say it could handle 30' of head? we only need 5' or so.

Also that pole has a 30 amp 220 outlet. a lot of heat can come out of that. Maybe we could salvage parts from an electric water heater and go from there.

I love the simple torch on a bent pipe idea. I've got one of those weed burner attachments that never gets used. 

Combine a couple of these devices and that water will be hot by mid afternoon, then leave it on electric mode for set it and forget it goodness.


Now whose got some jet ideas?...


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## kengore

Jets? Have every other person wear swim fins!


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## elcaposwimteam

For what its worth: my buddies from New Hampshire used an old (clean) radiator and just tossed it in the fire with a recirculating pump and hot water pumped into an old horse trough. Pretty simple really. As far as jets? Serve beans with every meal


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## deepsouthpaddler

Awesome info! I've got a lot more to work with now. I like the idea of jets.


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## matt cook

what about an old bucket boat for the tub? I'm sure it will be a little worse for wear afterwards, but there is always an old pos bucket around that needs more work to float than its worth. I have several if you wanna come to my house and experiment/make one for me.


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## afox

Best makeshift river hot tub ive seen:
On a middle fork trip my friends put a tarp in the back of their boat pulled the boat right upto the sunflower hot spring waterfall (flows right into the river) only took a few minutes to fill the boat up with fresh hot spring water and away they went down the river with 2 people enjoying the hot tub and one rowing. Definitely one of those "whatever the rich people are doing right now it can't be better than this" moments....


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