The one item you’ll need is an old cast-iron enamelled bath tub. The old-fashioned standard tub with feet, which used to be common in homes a generation ago, can withstand being heated by fire and will provide a safe, comfortable and long-lasting hot soak for your weary bones. These tubs can usually be found in the Buy ‘n Sell or by asking around. My tub cost $40, and this is about what you should expect to pay. Avoid going to antique shops where they charge a premium.
Only a cast-iron tub will do. The modern, lightweight tubs will not work for this purpose. The cast-irons tubs are heavy, and the most challenging part of building this ‘poor man’s’ hot tub is getting it to your home. You’ll need a friend or two and someone with a pickup truck to get it to your yard. Once the tub is on site, the fun begins.
How to Build a 'Poor Man's' Hot Tub
1. Prepare a clear, level site for the fire pit and tub.
You’re going to love your ‘poor man’s’ hot tub, so choose the location carefully since you’ll be spending lots of time there. The first consideration is fire safety, so be sure your site is well clear of brush, overhanging branches or any other flammable material. The ground should be level around the tub to make it safe for building a fire and for getting in and out the tub in slippery conditions.
2. Dig a low spot for the fire and line it with rocks.
Once the ground is cleared for the tub, and the dirt is removed down to mineral soil, dig a hollow spot for the fire pit. This should be about 18” below the bottom of the tub, to allow for the lining rocks and to create plenty of height space for the fire. The fire pit should be centered beneath the tub, but does not need to be as wide as the length of the tub. A pit roughly circular in proportion will suffice.
While you’re in digging mode, dig a depression where the tub will drain, and dig a small channel to direct the draining water away from the fire pit. This way the draining tub will not flood the fire pit. If someone else wants to start another tub of water heating, the fire pit will be ready to go.
3. Set bricks in place for the tub feet.
Measure the space between the feet on your tub and set bricks into the ground to serve as the base. Stack one or two bricks for each tub foot as necessary to achieve a level base, then backfill and tamp down the soil firmly around the bricks. It is important to use a carpenter’s level to ensure the tub is level both lengthwise and across from side to side. In setting your tub to level, it will be more stable and you’ll be able to fill it close to the top for a more enjoyable soak.
4. Seal spigot holes on tub.
A 2/3 full tub is not good enough for diehard hot-tubbers. Apply a ring of exterior silicone caulk around the three holes for the spigots and press a small square of plywood against it. Apply a similar square on the outside of the holes and through-bolt with a few small bolts with nuts and washers. This will let you fill your tub higher, so when you get in the water level will rise right to the top.
5. Set the tub on the footings and test it before using.
Get a friend to help you set the tub on its footings and check for stability. You might try sitting in it to make sure there’s no wobble, or you can just fill it with water and push down on the tub from the sides to be sure it is solid on the base. Now you’re ready to get some small pieces of firewood and prepare your tub for your maiden soak! Bring a book or set the radio nearby, because you’re going to be here a long time.
Tips for using your ‘cannibal-style’ hot tub:
1. Fill tub with water before starting the fire.
The tub must have water in it before starting the fire, or the enamel will be chipped away. The fire should be modest and in control at all times. It will take about 45 minutes to an hour for the water to heat up. Once the water is hot you can get in the tub, but don’t put out the fire. Let it keep going while you are in the tub, as this will let you stay in longer without the water getting cold.
2. Cover the tub with a sheet of plywood or similar material.
Cut a piece of plywood to the width and length of the tub. 1/2” plywood is ideal since it’s not too heavy. Set this ‘cover’ on the tub while the fire is burning to speed up the process of heating the water. Be sure to keep an eye on the fire to ensure flames do not climb too high and start to burn the edges of your cover.
3. Cut a ‘bum board’ from a piece of plywood.
When you step into the tub, the bottom will be hot. You’ll need a small board to sit on during your soak so you don’t get a hot seat. I use a piece of ¼” thick plywood cut to 16” x 24”. This is a perfect size because it is a little flexible when you sit on it, for added comfort, and it submerges easily under your weight. If you use a thicker board it will have more flotation, and will want to slip out to either side of you and rise to the surface when you are trying to sit on it.
4. Keep the hose alongside the tub while bathing.
This is important. The hose is right there for fire protection of course, but you can also use the hose to cool the water while you’re in the tub if the temperature gets too hot. (Remember, the fire is still burning. It will be just coals at this point but it still generates heat.) Keep the hose within reach so you don’t have to get out of the tub when you need it.
5. Keep a few pieces of wood within easy reach.
You can extend your soak by keeping the fire going while you’re bathing, since this will keep the water hot. Leave a few small chunks of wood within reach from the tub so you can simply drop a piece onto the coals if needed.
6. Soak with a friend? By all means!
Yes, you can fit two people in this tub. One person can sit at each end with legs extended and it is quite comfortable. Yes, it is intimate, so be sure you’re good friends!
This tub will last years and years, and I hope you enjoy it as I enjoy mine!