Rocket Mass Heater Workshop - September 2014

Workshop and Pyronaut Laboratory - September 2014

Rocket Mass Heater Cob Workshop September 19-21


The standard cob rocket mass heater is still the easiest to build from scratch, the most efficient, and, many feel, the most beautiful.

Unlike some of our past workshops, this will be a cob core (permanent) and a cob bench. Cob, cob, cob. As cobby as it can possibly be.

This workshop will, of course, be lead by Ernie and Erica Wisner, the world wide leaders and trainers in rocket stove technology. In addition to these two brilliant teachers, four other innovators have accepted our invitation to join the fun; their names and bios are below.

Pyronaut Laboratory September 22-26

Immediately after the workshop we will have five days of rocket mass heater innovation. This will feature the top six innovators in rocket mass heater technology: Ernie Wisner, Erica Wisner, Peter van den Berg, Tim Barker, Matt Walker and Chris McClellan. For this event, the clever idea is that each innovator will take on whatever aspect they feel like taking on and each innovator will be assigned two assistants (lab rats). So .... wanna be a lab rat?


Here are the details regarding what will be taught during the workshop. The participants will:

  1. gain experience in how to make cob the RIGHT way.
  2. gain experience in shaping cob into a bench.
  3. learn how to build a rocket mass heater core: a wood feed, a burn tunnel, a heat riser and, the trickiest of them all - a manifold.
  4. learn how to properly design a rocket mass heater for a site.
  5. listen to and participate in discussion of different styles of risers.

Basically, after this workshop you will be able to build your own Rocket Mass Heater. This means you will be able to heat your home with 80% to 90% less wood. The exhaust from that wood will be nearly pure steam and CO2 (a little smoke at the beginning). With this heater, the heat from one fire can last for days! Not only that, but you can build one in a day and half and folks have been building them for less than $20 (by scrounging for parts. $200 to $300 if you buy everything brand new). How could you pass that up?

While we are delighted to share as much information as possible with everyone via the free forums, online articles and videos, and by documenting workshops in DVD format as a more flexible option at lower cost, there is really no substitute for hands-on practice.

Ernie and Erica have taught workshops in which HVAC experts and fire marshalls were impressed with the amount of new training they gained. At the same time, novices (including one memorable participant who had never lit a match prior to the workshop) remain engaged as full participants, getting their hands dirty, making their own test models, and leave the workshop confident in their ability to apply their new skills on their own homesteads.

One point Erica and Ernie often make to novices is: "In a workshop, you have a dozen or more people all bringing their own questions and mistakes. You will get to see far more mistakes than you could ever anticipate on your own, and how to correct them. You will see common beginner mistakes and misconceptions that you might not have realized are common fail points, and advanced mistakes you might not be capable of making yourself until years later. To make all of these mistakes yourself, and work out the solutions on your own/online, could take weeks or years of labor and frustration. So if you don't bring at least one honest question or mistake to the workshop, you're not serving your fellow students."

"Dumb" questions are often the best kind; they reflect very common confusion about the complex, dynamic, and difficult-to-predict behavior of common materials and flowing systems."


The workshop will begin with Fire Science on the evening of Friday, September 19th at dusk. It will end on Sunday, the 21st at about 4 pm. Saturday and Sunday will be a mix of classroom time and hands on experience in building a rocket mass heater.

Detailed Itinerary

Friday (workshop)

4:00 pm to dusk:
Registration begins at 4:00 pm but it is optional to show up that early. If you arrive fifteen minutes before dusk, that will still be fine. If you do choose to arrive at 4:00, there will be networking and visiting and a meal around 6:00.
Dusk (about 7:00pm) to 9:00 pm:
Intro to fire science, evening campfire: Fire After Dark!

Saturday (workshop)

7:00 am: Breakfast
8:00 am: Tour of existing rocket mass heaters (Tipi, office, shop, house) plus wofati sites, lemon tree site, bee hut, etc.
10:00 am: break, Q & A, Review design principles.
10:15 am: Class begins: Masonry basics and practicum (stomp cob, stack bricks); Dry-stack masonry footing for bench; build Heat Riser.
12:30 pm: lunch - social time, share books or pictures.
1:30 pm: Lay out actual stove (firebox, pipes, bench, exhaust)
3:30 pm: break, Q & A, Review design principles.
3:45 pm: Build with mud - cob, cob, cob
6:00 pm: Regroup, ask questions...
7:00 pm: Dinner and visiting
8:00 pm: Campfire - sing, chat, roast marshmallows, and play with fire.
There will be an optional movie viewing, possibly one of the Wood Burning Stoves 2.0 DVDs.
10:00 pm: - Quiet returns.

Sunday (workshop)

7:00 am: Breakfast, planning for the finish.
8:00 am: Class begins - dig in and build it! Let's do the Mysterious Manifold before lunch.
10:00 am: Mid-morning break - quick tea/coffee and snack
12:30 pm: Continue building Rocket Mass Heater
12:30 pm: lunch - visiting
1:30 pm: Finish details, check connections, and test-fire the Rocket!
3:30 pm: Mid-afternoon break - fortify yourselves for the road... Wrap up - Q & A, books available, and thank you!

Sunday (limbo between workshop and pyronauts event)

6:30 pm: Dinner
7:30 pm: Campfire

Monday through Friday (pyronauts laboratory)

7:30 am: Breakfast
8:30 am: Clever Innovating
12:30 pm: Lunch
1:30 pm: Devious Innovating
5:30 pm: Dinner
6:30 pm: Plotting and Scheming from overly comfortable chairs

What to Bring

Here is a list of equipment we suggest you bring:

  • Comfortable clothes to get muddy in!
  • Protection for hands and feet: shoes/boots/callused toes, garden/builders' gloves.
  • Weather protection: hat, sunscreen, shades, layers; raingear if needed.
  • All necessary tools will be provided. If you bring personal tools, please mark them to avoid confusion. You might find useful: a pocket knofe or multi-tool, hammer, machete / camp ax, trowel, tinsnips, ball o' twine, general-purpose poking stick.
  • Learning tools: notepad & pencil, camera, tape-recorder, or Zen-like mental focus.
  • Joys to share: pictures of your dream house or "fixer-upper", project sketches, favorite snacks for Friday night, musical instrument to liven up the cob stomp or campfire.
  • Additional Tool Info: If you have your own tools for general masonry work, foundations, or metal-cutting, these are welcome too. (examples: level / plumbline; trowels or floats; cold chisels or masonry cutters; special gloves you use for mud work). The entire rocket mass heater process can be done with hand tools, which is nice for cost, safety, noise, and applying new skills at your own pace. Some power tools speed up the work, but may also speed up mistakes or risk of injury. Suitable power tools such as metal and masonry cutters, screw / bolt / rivet drivers, etc. may be brought and used by their owners; but not all students will be trained or expected to use power tools
  • If you have particular local materials you would like to try, bring a sample to share.

Pyronauts' Laboratories Attendees:

  • There is no telling what tools may come in handy for on-the-fly experimental prototypes. We encourage bringing your favorite travel tools, especially if you have anything hard-to-find or unusual. Innovators' work may include comparing stove performance (testers for emissions, thermal, or other factors would be lovely); working with castable refractories as well as standard firebrick or hand-formed earthen masonry; more extensive metal or wood-working (for making molds, and for metal stove components); and possibly the invention of entirely new processes.


Reserving a spot

Attendees have the option between the 2 day workshop, the 5 day Pyronaut Innovator, or a combination of the two. The workshop is limited to 25 students and the pyronaut event is limited to 12 lab rats. As long as these options show up, there are still spots available.


(the paypal stuff used to be here but was removed cuz everything is sold)

Work Trade

Work Trade is full!

There will be an option for work trade. If someone comes out to throw a shoulder in, they could be awarded a credit toward this workshop. If a person comes out and works a full week before the workshop, they can attend the two day workshop. This work will include the most boring and sweaty things we can think of! It might be chopping wood or building a trail, or digging a ditch or peeling logs.

If a person puts in two weeks, they can trade that for the workshop plus the pyronaut event.

For more info, click here.


We have beds, cots, tipis and tents. And there are some nearby lodges and cabins for rent. There is also a basic, but decent hotel about seven minutes away.

The price includes a spot to pitch a tent (and we will even provide the tents and sleeping bags - if needed), although there are a few bunks (some twin beds and some full sized beds) and tents currently available. We even have a few cots in a tipi available. For the people camping, we do have a compost toilet and a shower heated by a compost pile.

For more information, see this thread at permies.


In addition to all of this we will provide a ride to and from the airport for any participants flying into Missoula.

If you are driving here, we have plenty of parking.

Om nom nom nom nom! (food)

Workshop participants will be invited to dine with Paul. There is an optional meal on Friday night around 6:00pm. We will all dine together 3 meals a day on Saturday and Sunday of the RMH workshop, and 3 meals a day Mon.-Fri. of the Pyronaut Lab week. The food served will be organic or better. About 30% will probably come from this land and there will also be an effort to include wild foods.


Last but not least, workshop participants will also get a tour of all the projects at base camp and the laboratory. They will get to see two wofatis, the lemon tree project, the tipi with the rocket mass heater, the the solar "voltswagon" the "solar leviathan", the solar electric vehicles, solar electric tractor, solar electric sawmill, hugelkultur beds, berms, compost hot water showers, and more.

Additional Questions


If you have any more questions, refer to this thread at permies.

Contact Information

You can either email us at, or post questions to the Rocket Mass Heater Workshop thread at permies.

Ernie and Erica’s Bio

Ernie and Erica Wisner are a couple from Tonasket, WA. They learned about rocket stoves when Ernie apprenticed for Ianto Evans for about two years. Since then they have built over 700 rocket stoves worldwide.

Erica Wisner is the public face of their whole business. She is an experienced educator and project organizer so Ernie often refers to her as “the brains”. She is very passionate about making anything from scratch and helping other people to do so as well. She realizes it takes a while to gain confidence building with raw materials, but she is determined to teach people how to do so as quickly as possible. In her free time she enjoys art, masonry, baking, hiking, gardening, and aikido.

Ernie Wisner is semi-retired because of a disabling injury, but he still attends occasional workshops or special projects. He has extensive experience in everything you could think of regarding boats. He has built them, designed them, and competitively rowed them. Not only does Ernie have wide-range boat and rocket stove expertise, he also has been a firefighter, chocolatier, and ballet dancer.

This fabulous couple now makes their living by offering resources for practical projects. This includes free online information, design plans, and actual workshops on tons of different hands-on skills.


Erica and Ernie chose the top four Innovators in Rocket Mass Heater technology from all over the world. Erica tells us a bit more about why, "We were looking for a collection of people we'd like to meet, and whose work we share with other people who ask about a particular feature or function.

In addition to being excellent designers and prototype-builders in their various different ways, these four have also been excellent contributors to the grassroots research community, sharing their results with others through the forums at,,, and other sites.

There are half-a-dozen other worthy contributors who made our short list; and countless other excellent designers and masons out there perfecting their craft, but these four seemed to represent a good cross-section of what's going on in rocket mass heaters today."

Peter van den Berg

Born 1st of March 1946 in The Hague, Netherlands.
Lived in the same town since.
Formal education: Cabinet maker up to master.
Skills: Woodworking, bricklaying, plumbing, welding, plastering,electrical wiring, composites, making molds.
Work: Cabinet maker 17 years, composite specialist and mold maker at Fokker Aircraft 17 years, master of boats for Delft University among others, 14 years, retired since 2011.
Interested in efficient wood burning, mostly by way of masonry heaters for the last 30 years.
Tried to make a living building those heaters but gave up after 5 years.
Since 2007 investigating and developing rocket heater variants.
Designed and built my own passive, energy neutral house.

Links to his stuff:
Concerning Rocket Mass Heater
Concerning Horizontal Feed Rockets

Why Erica and Ernie chose Peter:
"Peter van den Berg was among the first to post emissions-testing data on rocket firebox models, and his attention to detail has led to two new firebox refinements that reduce emissions even further, and to the cast firebox currently in production by DragonHeaters."

Tim Barker

Tim has come a long way since his days as a diesel fitter mechanic and now spends his time between Australia and New Zealand as a semi professional pyromaniac and mad scientist teaching people how to burn stuff and make really cool machines and devices for low carbon living. He currently teaches Appropriate technology for the Koanga institute in New Zealand and Eternity Springs farm in Australia.

He has previously been farm manager for the Permaculture research Institute of Australia, power station operator/mechanicl, Adventure guide and professional turtle wrestler. His rocket stove and char making powered hot water systems, ovens and cookers reflect his passion for elegant simple and durable combustion technologies, other projects include gravity powered water pumps, solar thermal cookers and dryers , Pedal powered washing machines, cargo bikes, hovercraft, wooden boats and aquaponics to name a few. When he is not tinkering he can be found on Macleay island off the coast of Queensland Australia where he and his family live and are currently in the process of building a rammed earth house (with maybe a little sailing thrown in).

Link to his stuff:

Why Ernie and Erica chose Tim:
"Tim Barker, from Australia / NZ, built one of the most robust rocket water-heaters we've seen, capable of being run safely and maintained by a rotating student body on a permaculture teaching site."

Matt Walker

Matt is a designer, builder, and tinkerer who spends his time collecting firewood and growing food on his farm on the Olympic Peninsula. A lifelong wood burner with a curious mind, he has been designing and refining wood burning devices since childhood.

Link to his stuff:

Why Ernie and Erica chose Matt:
"Matt Walker solved the flame-viewing problem - twice, using different materials - and continues to innovate with bell-style heat capture, firebox ovens, and stovetop accessories."

Chris McClellan

Uncle Mud (aka Chris McClellan) raises free-range, organic children in the wilds of northeast Ohio. In his spare time he tinkers with, teaches, and publish books about cob building and Rocket Heaters.

Links to his stuff:
Super cheap rocket greenhouse heater
School bus heater with 35 gallon "bell" seat

Why Erica and Ernie chose Chris:
"Chris McClellan first caught our notice with a woodstove-mass-heater, and continues to explore the boundaries of what's possible with new / reclaimed materials, smaller spaces, and portable heaters (one of his latest is installed in a school bus)."