Advice on a RMH build in Hokkaido Japan

Hi Peter;  Everything looks good to me inside your rocket!
You are spot on telling folks they can not heat the earth and their home at the same time!  Insulate the floor! It's really simple!

You mentioned hot water.  I suggest you go to Matt Walkers site (walkerstoves.com) and check out his new water heater!  You could build one just like it!

Excellent update Peter!   Very useful information for any rocket scientist young or old to know about.

I'm curious if your monitoring your exhaust temperatures with a T&G Dragons breath thermometer (aka candy thermometer)? - available at fine stores across the planet. (Well that's what were saying anyways.)

Not sure if you have seen Matt's Live Chats before but after listening to his first 3, then participating in one just yesterday, I'm gleening all sorts of useful things from them.
Matt-Walkers-Stove-Chat-Live

Also, have you seen Matt's newest water heater? Looks pretty good.  water heater

Take care and look forward to seeing your future builds!

Thanks guys,

Really appreciate the quick response. I have looked at Matt’s new water heater contraption on his site. To be honest, I’m not really sure how it works yet. I’ll take a closer look and try to get my head around it. Might reach out to Matt again as well. Not sure we have enough space inside, but will have a think.

Also will take a look at Matt’s chats again. Haven’t seen his new ones and I’m sure they are filled with useful information.

Still haven’t gotten a candy thermometer. Probably should be top on our list of things to do. Will keep you posted on that.

On another note, I’ve been experimenting with adjusting the air intake on our J-tube. Been using bricks in different configurations in conjunction with our P-channel plate, built to Peter’s specifications. Trying to achieve a better ratio that doesn’t flood the system with too much air coming in through the mouth of the feed tub. Matt suggested using an old saucepan, flipped upside down. That way you can kind of regulate the air while still being able to use longer sticks in the feed tube. Bricks are too limiting. Sauce pan works pretty well, but it’s a bit primitive and not all that stable, balanced on top of protruding sticks.

The neighbor gave us some rusty junk the other day. We got a few of these cool old rusty soy sauce cans, that we’ve decided to use to use for an ash clean out can. Was sitting next to the fire the other day and saw it was almost the right to cover the feed tube and still long enough to cover any sticks coming out of the feed tube. (See photo below)

That got me thinking, what if I built a removable steel box, with built in P-channel to fit over the top of the feed tube. That way we would have consistent, undisturbed air intake, at the proper “Goldilocks” ratio and still be able to accommodate longer burn materials. (Again, see attached drawing below)

Think this would work and would not be very difficult to make.

Any thoughts?

Cheers and socially distancing beers,

Hi Peter;
I rarely have reason to want to cover the feed tube until the end of the burn.
Is there a reason you think it works better?
Occasionally during start up of my shop stove I have some smoke back , but it has a bell not a piped mass.  
Our 8" J in the studio with a piped mass only gets  bricks at the very end of the burn.

Your metal box , I suspect  would heat up over a few hrs and you might have issues with it igniting wood up high in the feed tube.

thomas rubino wrote:Hi Peter;
I rarely have reason to want to cover the feed tube until the end of the burn.
Is there a reason you think it works better?
Occasionally during start up of my shop stove I have some smoke back , but it has a bell not a piped mass.  
Our 8" J in the studio with a piped mass only gets  bricks at the very end of the burn.

Your metal box , I suspect  would heat up over a few hrs and you might have issues with it igniting wood up high in the feed tube.

Hey Thomas,

Was thinking it would work similar to a door on a batch box, only flipped virtually. If it’s sitting up high above the brick portion of the feed tube I was thinking it would work. To date Matt’s sauce pan hasn’t set any of the sticks on fire. Even if the wood ignited higher up in the metal box attachment all of the burning material would just fall into the bottom of the feed tube and continue to burn. Was planning to make it from some heavy scrap metal sheeting. (see photo below)

Thought the idea was to regulate air intake to get a better burn. Maybe I was misinterpreting it. You need more air than what the P-channel can provide alone?

Peter 🤔

Peter,   Last year I used a stainless steel pot I found at the thrift store (I cut the bottom out) as an extension to my feed tube and I was feeding 20" long logs which was nice to extend burn times. The lid was put on at various angles to accommodate air flow. It was about 1 1/2" away from the feed tube entrance at its closest points so it never got hot, only warm to the touch with all the incoming air flow to keep it cool.

The only problem with longer logs is that they sometimes get top heavy and fall over sideways sometimes creating a log jam and not feed properly. You always have to use branch free wood too in particular otherwise the same thing can happen - a smoldering log dangling by a little wee branch or knot on the side of the feed tube.

The one thing that I see with your diagram that you can't do is shut down the P channel as well when the fire is totally gone out. This opening will constantly be drawing air through the bench and slowly dissipating your stored heat out the chimney.

Generally, the idea is to run your rocket full boar from beginning to end without throttling it back (much) - no hard fast rules though. Just having the P channel to supply air is not enough. Its only there to make sure there is always a good supply of incoming air at the most crutial spot when the rest of the feed tube is full of wood.

Hi Peter;
This is my understanding, thought's and for what its worth, my opinion...
The p channel, by sticking past the roof of the burn tunnel creates a turbulence in the air flow. The uninterrupted cooler air mixes with the flames heading for the riser.  
A further improvement was a "trip wire" in the burn tunnel roof. Also creating a mix of air flow creating a more efficient burn.

The wood in the feed tube itself allows cooler air to rush past, thus keeping the fire lower at the burn tunnel and keeping itself below the combustion point.

What I envision happening at your home, knowing that you burn constant for a long time. Just like we do in the studio.
The attached P channel to your box will eventually transfer all the heat throughout the entire thing.
When/ if that happens, the wood in the feed tube could start burning and create a back draft filling the room with smoke.

It has always been my understanding,  to get the highly efficient & clean burn, that they are famous for.
A rocket stove of any design is meant to run wide open until the end of the burn.

Having said that Peter, it is very common for many users to partially restrict the incoming air to increase velocity.
In closing. We are rocket scientists and as such we must experiment!
You have the metal. If you have the time give it a go!

Thanks guys!

Some things to think about. Not sure when or if I’ll do it, but if I do will keep you posted. It would be a removable piece so could close the feed tube when not in use to avoid warm air loss through the p-channel. Maybe lose the hinged door portion as well. Use a piece of screen on top to help stop flying sparks.

Will keep tinkering...🤟🔥🤟

Hey folks,

Here’s a look at our build to date.

Thought you might like to see what it’s starting to look like. Still far from “done”, but still having fun and a bit closer to a cozy home with each new coat of mud.

Lots of projects on the go right now with the warmer weather, but will keep you posted with new developments on our build as we make time to play with renderings and finishes.

Hope everyone is safe and well.

Cheers Peter & Mimi⛰🌞🌞⛰

You've come a long ways my friend! That photo belongs on the cover of Good RMH magazine. Well done to the whole team!

Gerry Parent wrote:You've come a long ways my friend! That photo belongs on the cover of Good RMH magazine. Well done to the whole team!

Thanks Gerry!

Kind of like the fact that it’s a continuous work in progress. It’s not perfect, but as we live in it we are beginning to see what works and what could change. Best part to me is the flexibility of the natural materials. Decide to change something all we have to do is hack some dirt off and reconstitute it. I feel that leaving things a bit open ended make building a bit more versatile. Something we couldn’t have done with conventional modern building materials.

Till to start experimenting with the next rocket design I think. Build some stuff outside in the front garden. Was thinking of a double shoebox style design. Maybe something that we can tinker with and then adapt later into a water heating unit. Any thoughts there?

Should I take a look at Peter’s design? Would something else be a better option? Had a look at Matt’s Stove Chat. Will watch more later, now that I have internet again.

Any insight would be much appreciated.

Thanks again for all the help so far.

Cheers, Pete😎

I totally agree with you on that one Peter. Using natural materials is flexible in so many ways and is also way more easier to reflect your current needs and situations at the flick of a hammer and a splash of water.

I know very little of Peters double shoebox design enough to comment on. I do know that he had moved to a second generation known as the DSR2 and can be found on proboards.
Matt's riserless core could be similar and know he has come out with a water heater with plans just last week on his site.

Definitely keep us posted on your findings though as I would love to learn about what you have in mind also.

I’ll keep researching and thinking about what might work in the space then open a new thread on that topic when the time comes.

On another note, we have been foraging in the fields around the area recently. Been trying different dried reeds as kindling, as they are really abundant, light and easy to process. Of all the ones we have tried the ones pictured below seem to be working the best. They have hollow stalks and seem to burn really well. Placing a few on the bottom over a bed of wood shavings and then sticking them in the gaps between larger pieces of wood near the beginning of the firing to promote combustion. Have been tying them up with wire in large bundles, and hanging them from the top of the walls, away from the RMH barrel, to accelerate drying.

There does not seem to be any increase in the amount of ash in the burn chamber. Is there any reason why using these types of materials as kindling would be detrimental? I feel this seems to be a quick and easy way to collect a small formate fuel source which is light weight and simple to process.

Is this a good idea and should it be recommended to others. I want to continue to experiment with alternative fuel sources that are less time consuming to process.

Any thoughts or ideas would be much appreciated.

Cheers, Peter✌️🌞✌️

In 1971, a picture was taken of this ole timer who looks like he beat you to discovering your 'new' source of kindling. Someone thought it would make a great album cover for Led Zeppelin not realizing that this guy was just collecting kindling for his rocket stove at home too. Maybe if there ever is an album remake, we may see you on the next cover?

But seriously, even though I'm certainly no authority on kindling standards, I would say go for it.
I know there have been several threads discussing fire starters made from used butter wrappers, waxed boxes, junk mail and bacon lard which all could be considered garbage to some, so I can't see there being anything wrong with using a natural product that is dry and combusts well with no or little ash.
Your resourcefulness is always commendable Peter!



source

Didn’t even think of that. Good one Gerry!
I’ll take any comparison, to the greatest band that ever was, as a compliment.

I’ll keep burning stuff and see what happens. These bamboo bush stalks are looking promising as well and they are everywhere. Just take longer to dry, as they are much denser. I’m making sure to cut them between the nods so that we don’t get hot pockets of encapsulated air trapped in the fire, ready to explode. I’ll dry these and see how they go as well.

Tried re casting the bottom refectory brick for the feed tube. The bag of refectory cement was sitting in the shed all winter and had a bit more large chunks in it that when I first got it, from what I can remember. I went ahead with it anyway, seeing that it was left over and I figured it was worth a try. I followed PETER‘s advice, and only used as much water as I needed to make it pliable. The mold was coded with petroleum jelly as a mold release and I packed it in as soon as it was thoroughly mixed. Found that the dryer mix was more difficult to vibrate bubbles out of. Any advice in this area?

Because we are not pressed for time at this point I left it in the mold for 48 hours then after removing it from the mold kept it damp and covered with plastic for seven days. After that I let it air dry for two days. Today I decided to try to low temperature cure it a bit over an open fire. I only left it there for about 15 minutes on each side. I have noticed a few small surface cracks. Is this evidence that this will also fail due to spalling?

Here are a few images of the poor and the final product. I’m interested to continue experimenting further with castable refractory’s. Pre-existing high density refractory bricks are too limiting and CFB is a bit pricey. I’m tempted to try Carl’s Kansas City one recipe. I’ll let you know if that happens and if I find out anything interesting. Will definitely have a talk with him on the pro boards prior to trying anything of course.

Thanks again for all the support I’ll keep adding thank you for sharing please do the same.

Cheers, Pete✌️

Forgot the picture of the bamboo...🌞

Pulled out the old broken bottom brick last night and switched it for the one that I recently cast. New brick was in the mold for 48 hours, covered and kept damp for 7 days, then slowly fired a few times out side and then put on top of the burn barrel for a while, before going in the burn box.

Here are a few images.

Just thought I would point out that my perspective on some of these materials, build process, and functionality has changed a bit since starting this project. There is a good chance they will change again.

I remember being so worried about these castable bricks not looking perfect when I first cast them and being so concerned when they started spalling.

Now I realize, after you guys told me ten time, these bricks are really only there to serve as an abrasion shield. In a way they, especially the bottom one, can be thought of as almost sacrificial. Understand the importance of a strong ceiling configuration for safety, but other wise feel it’s pretty open to experimentation. Especially as the weather warms up and you don’t had the Siberian winds knocking on your door.

Failed brick crushed an reconstituted for grog in a new castable?

I’ll keep trying stuff.

🌞Peter🌞

PS- one thing I did notice is the new brick is a bit too small for the fire box. There are gaps around the brick. Has the fire box expanded over time? Just filled the gaps with fire ash so no issues.

So I was just out side on the front porch this morning early, listening to the bird singing and contemplating the meaning of life, when I notice what sounded like a fizzing can of carbonated soda. When I looked next to me I saw that the bucket, that I had put the remains of the spalled out old castable bottom brick in, was bubbling.

I’m assuming this is a reaction of the lye in the fire ash with rain water and maybe the aluminum bucket it’s sitting in.

Any scientists have an idea?  

Green ectoplasm on the brick?

So I was just out side on the front porch this morning early, listening to the bird singing and contemplating the meaning of life, when I notice what sounded like a fizzing can of carbonated soda. When I looked next to me I saw that the bucket, that I had put the remains of the spalled out old castable bottom brick in, was bubbling.

I’m assuming this is a reaction of the lye in the fire ash with rain water and maybe the aluminum bucket it’s sitting in.

Any scientists have an idea?  

Green ectoplasm on the brick?

Some chalk in the brick transformed into quicklime?  Doubtful. But hey, that could be an explanation!

Or it's hydrogen! Throw a match in there!

https://www.researchgate.net/publication/266220795_Hydrogen_Generation_From_Aluminum_In_A_Non-Consumable_Potassium_Hydroxide_Solution

Satamax Antone wrote:Some chalk in the brick transformed into quicklime?  Doubtful. But hey, that could be an explanation!

Or it's hydrogen! Throw a match in there!

https://www.researchgate.net/publication/266220795_Hydrogen_Generation_From_Aluminum_In_A_Non-Consumable_Potassium_Hydroxide_Solution

Hydrogen sounds cool.
Maybe maybe build a Rocket Mass Zeppelin?

My take on it is much less exciting than you fellows proposed but I would hazard a guess and say it was your super dry brick sucking up all that water and creating bubbles.
I know I have seen this happen when I put chunks of dried cob from a rmh rebuild into water and it bubbles for quite some time afterward.

Gerry Parent wrote:My take on it is much less exciting than you fellows proposed but I would hazard a guess and say it was your super dry brick sucking up all that water and creating bubbles.
I know I have seen this happen when I put chunks of dried cob from a rmh rebuild into water and it bubbles for quite some time afterward.

Could be right, but it sounds a bit like an Alka-Seltzer fizzing, so it makes me think there’s a chemical reaction.

This stuff makes me wish I had payed more attention in Chemistry class and less time trying to pick up the cute girl that sat at the lab table behind me. She was pretty cute though.

Guess there no better time than the present. I find it fascinating that so much can happen with the materials from the fire. Ash makes lye, burnt shells make lime and so on. Feel like the heater can create itself with a bit of help.

Will study up more... Peter🤓

Working on the house (🏡)

Found an old thermometer in a box I was unpacking today. Thought it was broken, so I checked it by boiling water and putting the end in. It read 100°C when the water boiled so I assumed it was good.

Drilled a hole in my outgoing flu pipe, one drill bit diameter smaller than the thermometer and then micro adjusted the hole size so that the thermometer could be forced in with a really tight fit. Nothing more than that. No welding, no high temp epoxy goop. Just tight fit.

Anyway, fired up the stove to see what the exhaust temps would look like. Been think about this for a while and Gerry just mentioned it agin in another thread. So here is a quick breakdown of where we sit.

Midday almost no wind overcast and wet outside from rain morning rain

Outside temperature around 10°C/50°F

Small diameter well dried hardwoods (mostly acacia) Feed tube not totally jammed with sticks.

7 minutes to 93°C/200°F (roughly)
13 minutes to 120°C/248°F

That was the max temperature, then let the fire burn down.

Did this a few times. All with about the same results.

This means I should be extracting a bit more heat I assume. More mass?
Exit gas numbers should be around mid 90°C/200°F correct?

Are these numbers useful? Or are they irrelevant, because they don’t accurately represent the normal temperatures in the dead of winter?

Here are a few images including the San Andreas Fault in our bench.

Cheers Peter⛰🌞⛰

Hi Peter;
You are now the proud owner of a used unbranded Tom & Gerry Dragon Breath Monitor !
We believe it should be a requirement on rmh's!
Yes , you are sending more heat up the chimney than you want to.
More mass/ raise your barrel.
Wet sandy clay in the fault line. Use your finger and just keep rubbing it in.

Hokkaido is BEAUTIFUL ! Wow Japan is very nice!

Soon everyone will know about Hokkaido because that is where future master builders Pete And Mimi Live!

Awesome Thomas!
Thank you...🙏🏽

Will play around and add more.

Should stay around 93°C/200°F, as Matt suggested?

Should I raise the barrel like Gerry did or make a metal extension like I was thinking before?

What exactly will the “raising the barrel” do from a scientific stand point? More metal would mean more immediate radiant heat exchange.

More mass around the base of the barrel. Should probably finish off the end of the bench as well. Bit of exposed barrel there as well.

Will work on the cracks.

Will letting the clay dry slowly in the coming weeks help maybe? You can’t throw a wet piece of pottery in a kiln with out it cracking. This would be the same as well know? Add mineral wool fibers to the mix?

Hokkaido is awesome in the spring and summer, just wish someone would send the black flies a message “you’re not welcome at the party!”

Thanks again, Peter & Mimi 🌈🤘🎃🤘🌈

Peter, here the local version, real local to southern alps. I have seen it in a local facebook group.





That's exactly the thing i was talking about.

Satamax Antone wrote:Peter, in France, we used to have a "hache paille"




But far more basic, with just a board with a ledge, and with a sort of huge knife, with a hook at the end.

Just like this one, for example.




They used to recycle old scythe for this. Making the end into a sort of metal rod, and bending it to form a hook, which would in turn fit in a ring at the end of the board.


And a far more modern way!

Or even newer!

Hello fellow rocketeers!

It’s been a while, I know.
Was in Tokyo since last November building sets and art directing projects for TV and movies. Mimi, Chimichanga and myself were away from the house all last winter. During our absence the front entrance to the house collapsed and ripped off from the rest of the house. No one was here, so no one got injured. To be honest after hearing that news I was about to throw in the towel, but the stress of city life and the longing for fresh mountain air has brought us back home.

I figured we might as well fix it up and see if we can wether the winter here this time around. Nothing fancy, but we’ve put in a few solid weeks and with the help of our neighbor, Mr. Yoshida san and scrapes from his garage and other miscellaneous stuff we collected we managed to put something back together for a little over $20 US. Here’s some images of the process and our build.

Also been tinkering with our RMH. Just decided to see what would happen if I added an extra half barrel to the drum riser. That all I had laying around rusty in the yard and all that our ceiling would allow. This is just something we threw together in a few hours. Literally just taped together with some stove tape, which is actually starting to peel off. But the results seem good and the room seems to get a fair bit more radiant  heat with the extra surface area.

I’m heading to Yoshida San’s house in the morning to work out and weld up a system to join up the barrels more securely. Will post some pictures and update with some thought and ideas as I go.

To Gerry, Mr. Gulch and everyone. Hope you are happy and well.

Keep the dream alive… Peter, Mimi and Chimichanga

Pictures didn’t upload🏔🌞🏔

Hi Peter, Mimi, chimichanga  Welcome BACK!!!
We have been wondering about you.
Glad you are back in the mountains where the air is fresh and the water is pure!
Looks like Mr Yoshida is helping build you an entryway that will not cave in from the heavy snow!
Two barrels can be easily joined with the clamp used to keep a removable lid on a barrel.
Or weld little tabs around the lip so it cannot slip off and seal with stove tape.

More photos

Hey Pete & Co. welcome back!
Thanks for the update, all the photos
and your commitment to backwoods living. I love that cool looking tenon cutter by the way.

It's cool to have some news.

I'm always keen on seing some timberframing from somewhere else. Is Yoshida san's tenonner, an old makita 5500s?

thomas rubino wrote:Hi Peter, Mimi, chimichanga  Welcome BACK!!!
We have been wondering about you.
Glad you are back in the mountains where the air is fresh and the water is pure!
Looks like Mr Yoshida is helping build you an entryway that will not cave in from the heavy snow!
Two barrels can be easily joined with the clamp used to keep a removable lid on a barrel.
Or weld little tabs around the lip so it cannot slip off and seal with stove tape.

Thanks Thomas for the tip. Yeah I had read back through some of your treads from earlier. Not sure I can get a clamp, but can do welding. I’ll keep you up to date as to what Mr. Yoshida san and myself come up with. 😎

Gerry Parent wrote: Hey Pete & Co. welcome back!
Thanks for the update, all the photos
and your commitment to backwoods living. I love that cool looking tenon cutter by the way.

Thanks Gerry! I can see shooting stars from the front yard once again.

Satamax Antone wrote:It's cool to have some news.

I'm always keen on seing some timberframing from somewhere else. Is Yoshida san's tenonner, an old makita 5500s?

The Tenonner is actually made by Hitachi, which is now been rebranded as Haikoki I believe. Here’s a few more pics. First time it’s been used in about 20 years he said. He gave use these two to have. Think they will be pretty useful for future projects for sure.

Have just been reading and enjoying your RMH thread Peter. Very Nice! And I'll mirror other's comments about the informative and quality of your posts.

Harvesting extra heat by adding the "half barrel" extension over the riser will tend to put more immediate heat into the space, and less into the mass, making for a bit slower warm up of the bench. If the space tends to overheat more quickly than before, that can be slowed down a bit by storing the heat in mass, which is already in place in the form of the stack of brick in the corner by the heat exchange barrel. May I suggest experimenting with dry stacking that stash of brick, forming a corner around the back and to the right of the barrel? Make the brick corner the same height as the top lip of the barrel. Obviously, leave an air-gap between the brick and the house wall/door/window. But between the brick and the heat exchange barrel, the brick can be right up against the barrel or as close as you like.

I use this technique on my 6" RMH, mainly as a heat shield between the heat exchange barrel and the adjacent wall. Works like a charm.

Peter Sedgwick wrote:

Satamax Antone wrote:It's cool to have some news.

I'm always keen on seing some timberframing from somewhere else. Is Yoshida san's tenonner, an old makita 5500s?

The Tenonner is actually made by Hitachi, which is now been rebranded as Haikoki I believe. Here’s a few more pics. First time it’s been used in about 20 years he said. He gave use these two to have. Think they will be pretty useful for future projects for sure.

Nice stuff, i'm keen on the tenonner. And on the chisels!