david pittaway

Jubilee Fly wrote:I love it!! So inspiring.
Whats the temp inside?

I still have not sourced a decent thermometer, but when I do, I'll let you know.

I have definitely got it "too hot" for some allegedly regular sauna users... including myself!

Aldo Caine wrote:Incredible job, looks great. What did you end up using for insulation? That's where I got stuck with my build (electric for now, but would like to make it rockety). I didn't feel comfortable with anything from the hardware store at high temperatures, so I just have wood with no insulation. Thanks

Insulation is not optional, imo. I used a layer of 'building-foil' insulation, and a product called 'Isotherm' in South Africa. The latter only reaches to about the bottom foot of the sauna walls, but is more than sufficient. In colder climates, I'd go all the way, and probably use the thickest option available!

Thanks Thomas!

thomas rubino wrote:
Are you able to rent it and recover your building costs?

I hope so!

thomas rubino wrote:
Then you will be known as David the sauna guy!

I'm already known as David the rocket guy. The mobile sauna is a great way to showcase the rocket tech.

thomas rubino wrote:Hi David;
In ten years you sell the whole business for a cool couple million and move on to your next cool invention!

Watch this space!

A mobile rocket sauna is on the loose in South Africa!!

Slightly shorter riser and radiator drum in order to keep the rocks/stones as low as possible (see 'the sauna Law of Loyly'). Some compensation upstream for this deviation from standard dimensions.

A possibly revolutionary feature of my approach is the BELL UNDER THE TOP BENCH. Yes, I do have to shout about this! Not only is the Law of Loyly met due to the lower radiator drum, the low bell also provides low heat throughout the sauna. I suspect that this is a sauna game-changer.

No, the bell under the top bench does not make the benches too hot to sit on. The bench slats possibly get hotter than usual, but I don't have a problem with it, and softer skins start with a towel between them and the slats.

Last week I ran the heater for 10 hours a day, 7 days in a row. All went perfectly. Used one third of the wood I took with for that event (South African Longboarding champs in Jbay).

Wood: knotty pine walls, yellow gum back-rests (sapless), and cedar bench slats.

This thing works amazingly!

You can follow the adventures of the sauna via 'AfriSauna' on Instagram if you like.

Cheers,
David

Two quick pics of the heater unit:





The sauna structure is not yet complete, and the clients have not yet used the sauna, so I cannot provide any info on the performance of the sauna.

A slight concern is that the structure is a simple overlapped plank structure - that's it. No insulation, no cladding, just one layer of wood. Lots of holes where the planks meet at the corners, and where the corrugated roof meets the walls.

Considering that the heater is a 20cm diameter unit, I reckon it'll create more than enough heat to compensate for the airy structure. It is located on the southern coast area of South Africa, so it's not like it gets very cold here.

I'll update on the performance of the sauna when I get feedback from the clients.

I build rocket heaters in South Africa.

Also rocket ovens, and rocket hot water systems. Rocket heaters for saunas too.

Some pictures here: https://www.perspectiveproject.co.za/rockets/

In my decade of using and building J-tube rockets, I have never seen any sign of a spark exiting the top of a flue pipe or chimney.

And I have stressed tested all the units by, for example, adding lots of dry pine to the test burns. LOTS!

Have you ever seen sparks exit your flue pipe? (I ask because someone I know is concerned about setting their thatched roof on fire if they install a rocket).

More specifically, let's limit things to an 8 inch system with a single drum heat radiator, with an elbow out the bottom side of the barrel into the flue pipe. I.e. no bell. A bigger brother version the one in the picture below.

In your opinion, what is the potential for sparks to exit the flue of an 8 inch version of the pictured 6 inch unit?

FYI:

Something of a follow-up to this topic/thread appears here:

Portable rocket oven

T Blankinship wrote:Where does the oven exhaust at?

Ah, yes, the exhaust. Your question links to my question here: rocket barrel oven - position of exhaust?. I explain the reason for the question there.

For this portable unit, I had to go with a single elbow from the exhaust hole exit into the flue pipe. Here's a pic of the exit hole:



As opposed to the double elbow from underneath the barrel in my immobile rocket oven:



I prefer the performance of the double-elbow shaped exit, perhaps for the reason I speculated about at rocket barrel oven - position of exhaust?

I needed to make a portable rocket oven.

Here's the result.

I cranked it to over 250 degrees C once, as displayed on the thermometer. Way too hot! I reckon the thermometer displays the temp at the front of the oven, with the back area getting much hotter.

The outer drum is insulated with 50mm ceramic fibre blanket, which is why the wooden stand doesn't burn.

Note that the unit can serve as an oven/heater combo, with a few mods, like removing fibre-blanket, making a metal stand, and painting with higher temp 'fire paint'.