RMH bathtub --- Think Tank

I get some of my best thinking done while simmering in the bathtub. This thread isn't about that, it's about choosing the best type of tub to insert into the cob, where others might place a bench.

A tub has been part of my heating system plan since I first bought the land 11 years ago. I'm certainly not seeking any advice on the advisability of including a tub.

The cottage is a total of about 550 sq ft. on 2 floors. I've decided that bathing will happen in the central living area of the lower floor. This floor is hugely over built. The RMH will rest over a big beam that has large concrete underpinning.

I've considered using a regular cast iron tub, but they are rather big.

Another option would be to mold the cob to a comfortable shape and use a sealer to water proof it. A pond liner would give great protection, but not the best look or ease of cleaning.

I really like the idea of using a large propane tank that is cut to a nice shape and set on a bit of an angle. There are quite fat tanks about 6 feet long and roughly the shape of a watermelon. One of these could function like a recliner. The wrap around back rest would provide some privacy.

There are many plastic items available at low cost. I've had many job site baths in garbage cans and Rubbermaid containers. Some rigid pond liners are a nice shape for a tub. The sleekest shapes that are available on the junk market are the lids if various roof top car carriers.

Another option would be tu find a nice sheet of aluminium and hammer it to shape, using my sand pile as a backstop.

I'm scouring the free adds for other tub shaped artifacts.

Google images has many great examples of tubs that have been built from or encased in cob.

Please let me know if you think of other artifacts that could be made into a nice tub.

The thermos lid in the last photo, is roughly the shape if the end of a propane tank. Those big tanks that are 4 feet in diameter, could each provide 2 small hot tubs and one culvert.

A smallish cast iron tub would be the best IMO. You could do any deck-mount tub you could find, too. But a self supported clawfoot would make things easier, just wrap the exhaust around it and cob it in place.

I like you soaking pod idea, not sure if it would really be that comfortable (no seat so you are always on your feet).

Is there an environmentally friendly epoxy you could use to seal the cob?

Or maybe a tile mosaic over the pond liner? Broken tile is cheap.

Dale : Even in a Filled Tub, if you are going to channel direct Heat against the bottom of your Creation you want to be setting on wood not against the bottom of the tank!

Protect your ''Wedding Tackle" as our British cousins call them ! Big AL !

If a sloped tank is used, a suitable seat would be added.

Yes, the classic claw foot is a good choice, but for me, only one without feet. I plan to completely encase all but the plumbing. A 5 foot claw foot with good feet is worth about $200, without feet, $50 or less. Tubs shorter than 5 feet are worth $450+

I've sold about 25 CF tubs in the past, but haven't had one in 4 years.

I despise tile cleaning. Whatever tub is used, it will be a one piece unit with no joints to fill or fail.

With a nicely molded cob base, it should be pretty simple to create a ferro cement tub. This material lends itself to the creation of a splash area and it can be colored to blend well with cob.

Inato's book page 65?

I think that a oblong Galv.steel stock tank would be good choice for a tub. Then you could enamel it if you wanted to and put wooden seats in it for relaxing.

Al, yes I've thought of the roasted nuts problem. I would make something to keep my ass off of the porcelain. Most likely, the tub will only touch cob. I plan to put a large tank of water on top of the riser. This will have a copper pipe which gravity feeds to the tub and has a tap at the tub end. The tank will have a lid which is raised for filling. Not sealed. No chance of steam explosion.

I've made hundreds of clay items in the past. This vase that I made, might be used in a shower feature. A small DC pump would fill the vase from the tub water and then water pours onto the bather.

I went to Pier One Importers, since they sell many large glass and clay items. My hope was to find a 6 foot clay pot with broken handles or a glass sink that is chipped. I was told that they get these things but rather than selling at a discount, stuff like that goes in the bin. My plan was to grab stuff at 90% off and cob over the defect.

I called a garden center that is open to the idea. They sell huge pots from China.

Glass items with the tiniest chip are not salable.

The second photo shows how hammered aluminium might look.

If I end up molding a tub into the cob, I'll base the shape on this hot tub reclining seat. I would then build a tray, similar to the ones found on baby high chairs, to hold food, a laptop and TV remote.

I mentioned watermelon shaped tanks earlier.

The last photo shows the sort of fat tank that would work as a recliner. After the opening is cut, the edge could be heated white hot with a tiger torch. A blacksmith's fork could be used to bend the metal back on itself so that a rounded edge is presented. Some hammering would be required. I think this is within my skill level as an amateur blacksmith.

Dale,
Probably no application, (www.dutchtub.nl ) but it's a nice design. It has a thermosiphon wood stove, with a wok as a damper (seriously you can do a stir-fry) Also the wood burning basket screws up and down to adjust water temp.

Also the Raboe stove (not with the tub) on the same site has a nice thermal mass as part of the flue. Reminds me of Kiko Denzlers ceramic hat.

edit: grammar, add email address

Then of course there is the Cowboy hot tub which uses a rubbermaid feeder feed tub.
http://www.cowboyhottubs.com/

Those round tubs are very close to what can be attained if a really large tank can be had. Each tank produces two tubs. We'd be left with a big pipe that could become a culvert, a play thing, or a hot damn heat riser. I already have two woks for sealing burn tubes.

If I were using the rounded ends, I'd build them on a cob base that comes up the sides and run rocket effluent under most of the tub. A flat floor grid would keep feet off of the hot rounded floor. We'd want to retain about 3 feet of the straight section of the tank to make it deep enough to be useful. I want something that holds a few hundred gallons, for a greenhouse/spa.

This is the Hot Tug.--- http://www.hottug.nl/fotos_en.htm --- It's a little boat that becomes a hot tub. A snorkel style wood burner heats the water.

The first photo implies that a creepy looking guy who is out of shape is likely to attract 3 girls for a typical outing. Seems realistic .

The two fellows in the second photo (Ted and Brian) rented this unit for $100 because Ted insisted that this was the ultimate machine to use for "trolling for chicks". They decided to stay dry until locating female company. But alas, they came up dry, so they are going home dry. They aren't on speaking terms right now. Brian keeps bringing up the fact that there are dozens of girls who visit the hot tub at the recreation center where it costs $3 to get in. Ted has had enough.

Top of the line models can set you back $35,000 --- I've figured out a way to do a redneck version for under $1000 --- No idea how you'll fill it with women.

I'm drawing up plans later. It won't be nearly as hokey as you might imagine.

Big Glass Aquarium --- Used aquariums often come up for free on Used Victoria. One of these set into the cob could provide a useful vessel for heating bath or dish water. Most are not made of tempered glass, so they pose a danger if smashed. A tank that is covered un all sides by cob, could not send big shards shooting across the living room. Breakage would cause a slow leak. The most likely way for the tank to be broken would be through temperature shock. It would need to be filled between firings, not filled with cold water when it's hot. Tests would need to be conducted and the temperature range of the caulking needs to be known. The most tedious bit would be installation of a drain pipe, without breaking the glass.
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Thick Plate or Tempered Glass --- Plate glass is readily available for free. It's a disposal problem at demolition projects. The sheets could be placed one at a time and cobbed into place. After it dries, caulk the joints. I would use smooth glass for the sides and use those grippy stickers that give grip on boat decks for the bottom. This allows for a comfortable slope to the back rest.

I bought an important tub accessory today. The DVD player has a screen that reverses and tilts. Don't want to splash water onto the controls. $70 down from $130. There's a remote. Tubs like these two examples sometimes come up cheaply or free.

I envision roasting in the tub while eating and watching movies and eating. That's nothing new for me except that this time the movie player will reside on a swivel arm like the ones in hospitals instead of sitting on the toilet. My cell phone with speaker system will also reside there along with food and drink.

Any updates on the rocket hot tub project? I'm scheming about one myself. . .

It seems like the way to go is something smooth, waterproof, heat resistant and hopefully nontoxic set into cob. I'm planning on something outdoors. We saw some giant stainless steel tanks for sale on Craigslist a while back, (no longer available) but the question was how much it would cost to cut the bottom 4 feet off? (also, how much to haul the thing from farm to workshop to our place in Portland)

Julia Winter wrote:Any updates on the rocket hot tub project? I'm scheming about one myself. . .

It seems like the way to go is something smooth, waterproof, heat resistant and hopefully nontoxic set into cob. I'm planning on something outdoors. We saw some giant stainless steel tanks for sale on Craigslist a while back, (no longer available) but the question was how much it would cost to cut the bottom 4 feet off? (also, how much to haul the thing from farm to workshop to our place in Portland)

I spent most farm time this year on growing stuff. I did acquire a big car top carrier for free. Bad roof mounts. After sitting in it' I decided that the sides were too straight. It sits by the garden and is filled with tools. It stays totally dry, due to the overlapping lip. By far the quickest and cheapest garden shed on Earth !!!

My tenant, Randy, picked up two free hot tubs. We're deciding where to put them. There's a huge glut of old tubs. I found out that the going rate for disposal is $150. I've advertised and won't take any more free ones.

The bathtub thing has been settled to some degree in that I now have the heat source.

I've gone over many possibilities on how to create the best bathtub for the space. And I think I've settled on one. Several years ago I made a part-time living, carving and selling bowls made from western red cedar driftwood.

I'm going to start watching the beaches closely for the perfect piece of driftwood to make a suitable giant bowl type tub. The piece of cedar would have to be a perfect specimen, since it represents about 20 hours of labor for me to make a bowl of that size and finish it with spar varnish.

https://permies.com/t/43542/rocket-stoves/Dale-Rocket-Powered-Mass-Heater