In case you haven’t been a RMH geek for a long period of time you may not know that Ianto Evans is regarded as many as the “Father of Rocket Mass Heaters”, at least that is my understanding. Ianto has been working with fire, building stoves and working with associated natural building techniques like cob, for decades. The biggest current names in the RMH field, like Kirk “Donkey” Mobert, Ernie & Erica Wisner, Art Ludwig and Paul Wheaton have all collaberated with Ianto, taken classes from Ianto or used Ianto’s designs as the basis for advancements in the science (or perhaps art) of Rocket Mass Heaters.
Rocket Mass Heaters Third Edition is not a long book, it’s only about 120 pages but it is packed with information, pictures, drawings and case studies. The book goes into exactly what makes a Rocket Mass Heater tick, how to build one and what materials to use. Rocket Mass Heaters in a nutshell consist of several main parts: The Burn Tunnel, Heat Riser, Feed Tube and the Mass or Thermal Battery and the exhaust pipe or Chimney.
One note of caution that comes up again and again in the book and should be noted by anyone thinking about building a RMH is that these heaters burn HOT. A typical wood stove will usually burn around 500 to 700 degrees Fahrenheit, the relatively low temperature is what makes them so dangerous, they don’t burn hot enough to burn off all the creosote and gasses and the typical temperature exiting the chimney can be in excess of 300 to 400 degrees. In a Rocket Mass Heater the temperatures in the burn tunnel can reach 1500 to 2000 degrees. That is hot enough to burn creosote, smoke and anything else that can cause a problem and the typical exit temperature at the chimney is around 150 to 180 degrees – much less likely to start a chimney fire. The high temperature burn is what make them so efficient but anytime you are working with fire pay attention!
The book starts out with a description of what a Rocket Mass Heater is, how it functions and outlines what they are and what they aren’t. It’s pointed out if you are looking for a “throw some wood in and leave for the day” fireplace then a RMH is probably not for you. The middle section of the book discusses in detail how to build a RMH, what kinds of materials you can build it with and the care and feeding after you have it built. The final section covers safety precautions, case studies of actual RMH builds and information on additional resources.
At $20.00 this book is a must have if you are interested in Rocket Mass Heaters or just want to read about cool things you can build that involve fire. I highly recommend it.
The second morning of the tour started at the Fisher Price House (FPH). Paul and Jocelyn call it that because it’s a double-wide trailer, mostly made of plastic and almost an air-tight plastic baggie. Their goal is eventually to move to a wofati up on the lab but at this time staying in the FPH allows them to get the outside work done that moves projects along and provide the basics for all the visitors that Paul’s ongoing projects attract.
There are people that call Paul gruff and hard to be around and that might be some people’s perception. I would say that Paul and Jocelyn open their home to a wide and varied mix of people. Some of the people that I have read about that they have welcomed in the past I doubt I would have let into my home. And, at the first sign of the ingratitude that has darkened their doorstep on occasion, I would have booted out or had arrested some of the folks that have heaped unwanted and probably unfounded abuse on on my hosts.
Paul has some fairly strong opinions on a number of topics and I have no problem with that. I have a lot of strong opinions on a number of topics myself. Paul seems to have actually mastered the ability to let others speak, listen to their words and then, after they are done, discuss the subject with a well thought out and reasoned response. I, myself, am still trying every day to be fair-minded, reasonable and thoughtful and there are a lot of days I struggle with each leg of that stool. Paul actually seems to walk the walk and I applaud him for that.
I had listened to most of Paul’s podcasts and the thing I was actually most worried about was that I would be disrespectful in some way (it might be a shock to some people that know me that I don’t actually have the best social skills on the planet) that would cause us to not be able to converse on a reasonable level. I don’t agree with everything Paul has tried to do, or the way he has tried to do it, but the man has put an enormous effort into moving Permaculture and Community forward and there is no denying (at least from my perspective) that he is moving things forward and shaking things up in way that no one else is and moving forward in a positive way.
So, to get back on point, Paul invited us to come into his home for a look at the Rocket Mass Heater that is in the Fisher Price House and to spend some time discussing the care and feeding of a RMH on a daily basis.
We spent a productive morning hearing about their experiences actually having a working rocket mass heater in their home. We actually got to fire it up (I didn’t get to light that one but I did get a chance to light another later) and see how it worked first hand. It’s an amazing appliance and I can’t wait to start learning how to build one myself. After learning about the FPH RMH we then went and toured the rest of the lab.
You can see all the amazing things we also got to learn about at Permies.com.
Our second day of the tour started at what Paul and Jocelyn call the “Fisher Price House”. The Fisher Price House (FPH for short) is a double-wide mobile home that has been basically permanently installed on a granite slab that was cleared in the side of a mountain. It’s mostly made of plastic and chemicals, hence the moniker FPH. Paul also calls it “an air-tight baggie” because all of the doors, windows and joints are sealed so tight there is almost no air-flow in the house.
There was quite a bit of discussion while I was there about how homes should “breathe” and how after years of mandating minimum levels of insulation and tightening up on home regulations the government finally got some studies done that showed there really should be a minimum rate of air exchange to keep people in structures healthy and reversed their policies. All of that was mostly an aside, the air-flow discussions primarily centered around the effect of proper air-flow and draw to keep Rocket Mass Heaters working correctly.
There is a beautiful proof of concept Rocket Mass Heater in the FPH.
The barrel on this RMH is made of stainless steel and is really quite striking. The thing about this RMH that makes it special is it is the first “pebble style” RMH build. For those not familiar the “Mass” in Rocket Mass Heaters is used to store the heat produced by the system and release it slowly over time, that is part of what makes them so efficient. Typically the mass is made out of Cob, which is a mixture of sand, clay, straw and water. In a pebble style heater the mass is primarily large-ish rocks that are surrounded by pebble size rocks contained in a wooden frame. Paul’s also has a granite top to the mass “bench” so it also looks very nice and is useful at the same time. I’ve been told in the winter they put their clothes drying racks above the bench (Permaculture function stacking at it’s best)!
When Paul, Donkey and Ernie Wisner built the FPH RMH (how’s that for acronyms?) they originally tired venting it out the wall, just to see if it could be done. It turns out it can, but it did not draw well on cold days. They re-routed the chimney through the roof, as is typical with most wood stoves, and that did the trick. Paul figures that his pebble style bench and the stainless steel barrel make this stove about 30% less efficient in actual heat generation and retention than a cob style with a normal metal barrel but he still typically only runs it a few hours every couple of days in the middle of a Montana Winter.
We spent a bit of time in the house, firing up the Rocket Mass Heater, and discussing design tricks and I can personally attest that it didn’t take long for the room to be cozy and it stayed that way long after the fire was out.
So at Wheaton Labs they encourage you to do your number one “bidness” anywhere on the property to return the nitrogen and minerals back to the environment. They also ask that you eat organic or better especially while you are on property for myriad and various reasons that you can look up on their website at permies.com. For your other functions there are multiple locations on the property that have various different types of “willow feeders”.
The concept behind the willow feeders is that willow trees and cottonwoods love excess nitrogen. After human byproducts are stored long enough to kill all the pathogens the remaining composted nutrients left behind are still too “hot” to put around most plants and most people have a natural aversion to composting in the garden with human waste (even though that was the practice in Asia for thousands of years and still is on-going but that is a discussion for another time). Turns out however that willows and cottonwoods will take as much of that kind of stuff as possible and turn it into oxygen and wood and such.
So the “willow feeders” at the Labs are more efficient than an outhouse and I can personally attest that they don’t smell and they are very clean. I’ve probably used more out-houses and porta-potties over my lifetime than most folks and I can tell you personally that the willow feeders are way more civilized than anything else of that nature that I have ever used. The biggest hassle factor is having to get mostly dressed if the weather is not good to use them.
We also got to take a look at a project that was built by a couple that was staying in the tipi. Yep, you read that right, Paul has a tipi on his property that is available for rent and contains a rocket mass heater.
It’s a full size tipi and has a rocket mass heater and circular thermal mass bench inside. Paul told us the first year it was on a property a couple stayed in it over the winter. One morning they got up, put on their outdoor clothes, came out side and found out it was 25 degrees below zero! Inside they said they had the Rocket Mass Heater going the previous day and when they got up it felt like 50 – 55 degrees out. They were shocked by the outside temp. And that was in an uninsulated tipi with canvas walls. Pretty amazing stuff!
Anyway, while the couple was staying onsite they wanted to practice their round wood timber framing skills so in their own time they built a skiddable “bee hut”.
There are a lot of black bears in the area and black bears love honey, so they added a solar panel and an electric fence around the structure that is powerful enough to discourage bears without permanently hurting them. The straw bales you see around the hive are in preparation for the coming winter to help the bees maintain the temperature in the hive and make it easier on them. It also cuts down on the wind and the roof cuts down on the rain and snow. Bees typically maintain their hive temperature in the 90 to 95 degree range all year round so cutting down on wind, rain helps a lot.
Allerton Abbey was to be the primary focus of the upcoming Natural Builders week and there were some really cool people coming into work on that and I will cover that in a future post. On this day I got to fire up the Batch Box style Rocket Mass Heater that was in the abbey. It appears the trick to successfully starting any Rocket heater or stove is to start a small fire in the back to warm the heat riser and then build the fire more towards the front (batch box) or add more wood to the infeed (J-Tube) once the unit is drawing well. If you don’t, you’ll get smoke (and Paul will explain why that is bad and look at you funny).
This particular heater is built with a glass top from a regular stove so you can see the fire and uses a pyrex casserole dish lid as the fire feed door. Without a door on these style Rocket Mass Heater/Stoves they are not finished and will not operate properly – that is one of Paul’s biggest pet peeves with this style. People start building, don’t finish or build it wrong, then say “Rocket Mass Heaters don’t work”. They do work but this style build is not for the novice, so it’s recommended you do others before you tackle this type.
I will say you could see the fire through the glass cook top and it was wild to watch it burn sideways, then roll towards the center of the chamber in elongated tubes like sideways fire tornadoes. Erica Wisner explains about Fire Science on their website and she also has a booklet called “The Art of Fire” that you can purchase that is super informative and interesting about how fire behave in various environments and conditions. I learned a lot by seeing all of the different Rocket Mass Heaters and Stoves and I am super glad I made the trip.
Paul’s property certainly has it’s share of beauty and charm. The area where the labs are located is somewhat on the side of a mountain, at least that’s what people from Kansas would call it, maybe in Montana it’s a big hill? A portion of it overlooks a steep slope down to a river and on the mornings I was there the mist and fog as you came out of Cooper Cabin was surreal and quite an experience.
Anyway, the tour continued with a visit to the interior of Cooper Cabin.
The front wall of the cabin has mostly glass so there is a lot of light coming in. The floor is finished in wood, although Paul hopes that eventually that will be converted to a Linseed Oil floor. I need to do more research on that – anyone familiar with that type of floor?
There are actually two experimental Rocket Mass devices in the cabin. The first is a Batch Box style Rocket Cook Stove. Batch Box RMH’s have a door and have a different internal configuration for gas pathways and such. Paul is not a huge fan because they are not as simple as a “J-Tube” type (we’ll get to that in a moment) and typically require more “fiddling” to run well. If you are interested in listening to experts discuss it there is a podcast here.
The second is what would be considered a “normal” J-Tube style Rocket Mass Heater with a Cob Bench providing the “mass”.
They are called “J-Tube” style because the wood feeds in vertically in the front (you can see the fire and wood feed towards the bottom of the picture above) and the burn chamber inside runs horizontally and then connects to an insulated vertical heat riser contained inside the barrel in the picture above. It is really a trip to watch flame burn sideways along the bottom of the burn chamber. The whole burn chamber is encased in cob and there is exhaust pipe that goes all through the bench to heat up the mass. Rocket Mass Heaters if running correctly burn between 1200 and 2300 degrees, burning up all the smoke, creosote and everything else combustible and then releasing some CO2 and water vapor that vents out the chimney.
The heater pictured above is in Erica and Ernie Wisner’s Rocket Mass Heater Builder’s Guide which is probably the most definitive guide on Rocket Mass Heaters currently available.
For those of you who aren’t familiar with Paul Wheaton and Wheaton Labs his property is divided into two parts – “Base Camp” where the current home and shop is located and “Wheaton Labs” which is a larger section of property where the Ant Village (we’ll cover that soon, I promise) and a lot of the other experimental structures are located. He calls it the Lab to make sure everyone remembers that the goal here is to experiment and prove concepts, not necessarily to churn out a finished product.
After the Pizza Party there was a bit of a mix-up on Friday night about where I would be bunking and Jocelyn graciously extended an offer to me to sleep the first evening on the couch in the Fisher Price House (they call it that because it’s a double-wide trailer made mostly of plastic) which I happily accepted. I helped her and Chef Ron with the dishes from the party and ended up turning in fairly late. Due to the time zone change and the length of my trip I had no trouble getting to sleep almost instantly.
I found out the next morning that Paul and Jocelyn tend to get up around 5:30 am. Paul was very kind and was being quiet in an attempt to let me sleep in. It turns out that Paul’s version of attempting to “be quiet” is quite adorable for a 6′ 4″ large man although it’s not actually very quiet. I appreciated the effort but the early wake-up was fine because I was excited to be up and start the day. The tour and the chance to see and play with all the Rocket Mass Heaters I had been reading about was why I drove to Montana in the first place.
Chef Ron, one of the tour participants, had come in the day before from Washington and helped Jocelyn prep everything for the pizza party. Chef Ron really outdid himself making a breakfast casserole with the leftovers and making homemade biscuits to boot. He told me he had never been in Jocelyn’s kitchen prior to the day before but he had found everything he needed almost immediately. I figured that was a) because Jocelyn rocks as a cook and a person and b) he’s a chef, and people who cook tend put things they use the most nearest where they use them. After breakfast the group of tour participants gathered together and carpooled in various vehicles up to the Lab area.
The first thing we saw when we arrived at the first Lab location was the Cooper Cabin.
Cooper Cabin is a WOFATI which stands for Woodland Oehler Freaky-Cheap Annual Thermalized Inertia structure. The Oehler stands for Mike Oehler who was a designer of underground earth houses who recently passed away. Mike was the author of the $50 Dollars and up Underground House Book and apparently quite a character based on the stories Paul was telling all weekend.
The WOFATI is designed to store heat in the summer and release it in the winter, maintaining a year round temperature without heating or cooling the structure. The Cooper Cabin is not completely finished but very close and Paul is hoping to have someone or a couple of someones live in the structure for year to document the conditions and prove that it works. If you are interested in helping out with that project let me know or contact Paul at Permies.com and let him know you want to be involved in the Thermal Inertia test.
The next project we looked at was the skiddable Wood Shed.
The wood shed was built as a place to store boards they have milled with their portable saw mill. Recently sawed green lumber needs to dry for a considerable period of time before being used in structures to prevent shrinkage. There is a style of building using green logs, called Round Wood Timber Framing, that actually takes advantage of the shrinking to tighten the joints of a build but that’s a topic for another post. The Wood Shed was built by a novice builder as their first natural timber build and it’s not perfect but it does the job.
We then got a look at Paul’s Solar Leviathan.
The Solar Leviathan is a portable solar charging station that has multiple solar panels mounted on a frame built onto a trailer that Paul’s brother welded together. The wheels look out of whack because the type of suspension they built has both wheels in a kind of floating frame, attached to a axle to allow for being driven over rough terrain. The solar inverter and batteries are contained inside the trailer making it a completely self-contained mobile power station. Very, very, cool, especially if you are off-grid and want to run an electric chainsaw, charge up your cellphone and have lights in a wofati cabin at night.
The next structure we looked at was the Canning Kitchen.
The canning kitchen is a skiddable structure (skiddable means it’s designed to be hooked up with chains to a vehicle of some type and dragged to a new location) built to make canning in the summer more bearable by performing all the heated operations outside. All the blue food grade barrels you see in the picture are for water storage and the kitchen sink on the lower right side of the picture has a manual foot pump that allows for running water.
The structure is designed with an open bay (lower right side) that you can insert a module unit into depending on what you need. When used as a canning kitchen they can put a Rocket Mass Stove for heating water into the bay or they can put the Rocket Mass Oven into the bay and use the shelves for food prep. The structure is about 65-80 percent finished but is certainly usable.
The drive from Billings to Missoula was only about 4 1/2 hours so I slept in a little bit, went down to the continental breakfast, had a nice chat with the lady who was serving (unfortunately I did not get her name) and continued on my way. The event I was attending at Wheaton Labs was a get-together for some of the folks who had supported Paul’s Rocket Stove Kickstarter. Paul was having a natural builder’s event starting the week after so he had some natural building rock stars coming in for the event and since I was coming in from the East I was asked if I could pick up Chris “Uncle Mud” McClellan at the Missoula International Airport. I was happy to do it (basically that was like asking a teenage girl if they would like to meet Taylor Swift).
I got into Missoula, MT quite a bit before the plane was scheduled to arrive so I did some grocery shopping and went to lunch at a place called the Mackenzie River Pizza Company. It’s a great pizza joint and if you are passing through Missoula I highly recommend stopping in for a slice. After lunch and a look around town I went to the airport to pick up Uncle Mud. I had seen him in person the year before at the Mother Earth News Fair in Topeka, KS putting on a straw bale building demonstration and was looking forward to giving him a ride. Uncle Mud turned out to be just as genuine as he appears when putting on a workshop and his enthusiasm for all things Rocket Stove and Natural Building related is apparent in every conversation he has. The other thing that impressed me was his dedication to family and I was honored to spend the time with him.
By the time we arrived at Wheaton Labs the Rocket Stove Pizza Party of 2018 was in full swing and just like that I was standing in a place I had been reading about for two plus years and meeting people that I been hearing about and reading about for longer than that. Just for the record Paul Wheaton is pretty much a giant. He’s 6’4″ tall and a presence in any room he is in, even if he’s not standing. Jocelyn Campbell might possibly be one of the nicest people I have ever had the pleasure to meet and is an excellent cook as the next few days attested.
The first night of the event was cooking pizza in the Rocket Stove featured in the Kickstarter video, eating good food and getting to meet the people who I would be spending the next couple of days with. It turned out that the people supporting Paul in the Kickstarter and coming together to spend time in the labs and talk Permaculture came from all over and many different walks of life. A chef turned farmer, engineers, architects, IT geeks, retired administrators, homesteaders and many others. A diverse group that actually reflected in so many ways the diversity that Permaculture strives for.
After a few hours of good food and lots of stories and introductions the various participants separated to go to the various campsites and rented structures around the property and turn in for the night.
Journey to Wheaton Labs Day 2 started pretty well. Up and on the road by 7:30 am, a little later than I planned but not by much. Kansas is much prettier in the daytime. Many people think of Kansas as flat. That is mostly true for the East-West drive, but we do have the Flint Hills which are beautiful and the North-South drive has it’s fair share of reasonable hills. No mountains but there is definitely elevation change. In the western part of the state I was driving through with a little bit of imagination you can picture what it might have been like hundreds of years ago, covered in grass 20 feet tall and herds of Bison so big you couldn’t see them all. Too bad all that is mostly gone except for a few places where they have protected it.
Soon enough I entered eastern Colorado. The scenery changes very quickly and it gets colder, you start to go up in elevation as you come closer to Denver. Fortunately my route passed by Denver but it did go partway on a three-lane highway between Denver and Fort Collins that eventually went down to two lanes. If you like a leisurely scenic drive avoid traveling that highway at all costs. Even in the late morning on a Thursday it was wall-to-wall traffic. Not as bad as the corridor from Oklahoma City, OK to Dallas, TX, but pretty bad.
The good news is that once past Fort Collins everything thinned out and the traffic became lighter and sparser as I neared Wyoming. Wyoming has the aura of the Marlboro Man, riding his horse across vast, untamed prairie. There are wide open spaces and some mountains. A very pretty drive through lots of small towns and spread-out ranches. I could easily see myself living in Wyoming – in the Summer. Winters there are pretty harsh from what I understand and I’m not really a winter guy.
Once I finally got into Montana it was gorgeous. The whole trip on Thursday had very variable weather and temperatures through every state and time zone. I went from moderate rains and 50 degrees to sunny and 72 degrees, back down to the mid 30’s and rainy again and it was happening about every 30-60 minutes. Very interesting. I finally got into Billings, MT, the Capital, about 7:30 pm. I was checked into the Sleep Inn by a nice, friendly young lady named Alicia. I spoke on the phone with the lovely Miss Mercy and then got settled in for the night.
I started my trip yesterday after work (yes, you can have a tiny sustainable life and still have a day job and sometimes it’s what funds your projects) with much fanfare from Miss Mercy who was very exited about my trip. We have a great relationship so I’m sure she was just happy for me to go play with Rocket stuff and not just happy to see me go. I was hoping to get out of Kansas the first night of traveling but it turns out that in flurry of activity prior to leaving I had programmed the wrong route into my Garmin and ended up traveling mostly straight West through Kansas instead of North into Nebraska.
In case you have not ever looked at Kansas (and I can understand why you might not, I probably haven’t looked too closely at your state) it is kind of a rectangle, so it is much wider than longer on the East-West vs. North-South orientation. It got dark and by the time I noticed I was passing Manhattan, KS instead of getting a “Welcome to Nebraska” sign I finally realized I was heading West instead of North. Probably most of you would not make that kind of mistake but sometimes proof that everyone is human does come out in a weird ways. My body wanted to go West, an electronic device sent me West, I went West…. And immediately ended up driving for several hours in extreme crosswinds. Crosswinds that move your vehicle sideways in lurches and send tumbleweeds and cows flying past your window. After three hours of that and having been at work all day I decided discretion was the better part of valor and got a room at a hotel in Hays, Kansas.
After a reasonable nights sleep (there was an all-night gas station across from my hotel room and the window blinds in the room were just for show, so more light than needed), a quick continental breakfast I was on my way…
For quite some time now (at least two years) I have been participating/lurking at the largest Permaculture site online, Permies.com. If you are not familiar with the site Permies is run by a gentleman by the name of Paul Wheaton who in his own words is “bonkers about permaculture”. No less a permaculture dignitary than Geoff Lawton named Paul “The Duke of Permaculture”. Permies is a fascinating place to hang out. There are forums for almost every subject related to permaculture and regenerative growing that you can imagine, forums for raising animals, creating berms, hugelkultur beds and everything else you can think of.
Paul also has a YouTube channel and over 400 podcasts on a mountain of different subjects. Paul has just completed successfully getting funded for his 7th Kickstarter project. The current project is going to be a 2 hour DVD explaining what a Rocket Oven is and how to build one. For people not familiar with Rocket Mass Heater / Rocket Oven technology it is a super-efficient way to heat a space, in case of the Rocket Mass Heater, or cook with, in the case of the Rocket Oven. The Rocket Oven burns a small amount of wood and functions like a normal oven, only more efficiently. I am a supporter of this particular Kickstarter and am looking forward to building one of these ovens and trying it out. Those of you who know me, and those of you joining us on our journey through a Tiny Sustainable Life, know I love projects and I am really looking forward to this one.
I’m currently in the middle of building an ornamental pond in our back yard (more on that in future posts). What are you building/making? How about projects you started but never finished? What happened with that?