• Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education skip experiences global resources cider press projects digital market permies.com private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Anne Miller
  • Nicole Alderman
  • r ranson
  • Pearl Sutton
  • Mike Haasl
  • paul wheaton
stewards:
  • Joylynn Hardesty
  • Dave Burton
  • Joseph Lofthouse
master gardeners:
  • jordan barton
  • Greg Martin
gardeners:
  • Carla Burke
  • Ash Jackson
  • Kate Downham

Jesse's Modular RMH Experiment

 
Posts: 61
Location: Nyack, NY
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Jesse, et al

This company makes prepared vermiculite mortar for fire resistance / fire insulation.

http://www.pullrhenen.nl/thermisch/en/vermiculite_mortel.html

Note that the product description suggests that the finished weight is approximately 20% of the weight of mortar alone; that seems to suggest a 4:1 or 5:1 ratio of vermiculite to refractory? mortar. The page shows a table with given ratios from 1:2, 1:3, 1:4, 1:5, up to 1:12. But the table isn't clear as to which material each side of the ratio refers. It seems here to suggest mortar:vermiculite (mortar/vermiculite).

What do you think?
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Naturally, that perlite mortar or vermiculite mortar from Pull Rhenen seems ideal, but I don't see it for sale anywhere! Perhaps the next best thing is the vermiculite or perlite with pre-mixed refractory mortar at the 4:1 ratio, maybe 5:1 if we can get away with it.
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thinking a little more along the lines of reusable forms.... That same guy that did the 5-gallon plastic drum rocket stove with vermiculite and refractory did it with plastic plumbing pipe. He used 4" pipe, coating it with used motor oil. First he poured the mortar mix into the bottom of the bucket, then setup the pipes, then poured the rest of the mortar mix over the pipes and up to the top of the bucket. Once the mortar set, he slipped the pipes out lickity split in 5 seconds, real simple.

Soooo.... Perhaps you could easily re-use the outside of the cast box form, done in plywood, and swap 4", 6", 8" or even 10" pipe depending on whatever size system you are building.

While I think I prefer the square burn tunnel and feed designs, I like the idea of reusable forms like this.
 
Posts: 245
Location: near Houston, TX; zone 8b
3
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

This company makes prepared vermiculite mortar for fire resistance / fire insulation.



This sort of material is suitable for the heat riser, but is probably not sturdy enough to put up with jamming wood into it for the burn tunnel portion of the rocket heater. I believe you will find it is very crumbly and easily broken.

Perhaps you could easily re-use the outside of the cast box form, done in plywood, and swap 4", 6", 8" or even 10" pipe depending on whatever size system you are building.


The problem with this idea is that the length of the burn tunnel needs to match the internal "Cross-Sectional Area".
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Ok I can understand that. Aside from swapping the different sizes, separate reusable forms for each size might still be a useful approach....
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Then again....

Perhaps we can simplify the burn tunnel and the riser with ceramic board?

This stuff looks great!

http://skylinecomponents.com/In-Stock_CeramicFiber.html

Would you need 1" or 2" board, at what temperature rating? 1800, 2100, 2300, 2400?

Seems like we could easily get away with 2" 2300 2x3 sheet, $59. The 1" stuff is $35.

I found the 2" 2300 2x3 on eBay for $119, free shipping.
 
Cindy Mathieu
Posts: 245
Location: near Houston, TX; zone 8b
3
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Have you checked the modulus of rupture on that board after its been heated?

Is it tough enough to put up with pieces of wood being jammed from the feed tube into the board?
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Cindy Mathieu wrote:Have you checked the modulus of rupture on that board after its been heated?

Is it tough enough to put up with pieces of wood being jammed from the feed tube into the board?



Tough cookie this stuff is hard to figure!
 
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Here are a couple of 1/2 scale molds (the first to make it this far) almost ready for the maiden slip casting attempt:

P1010434.JPG
[Thumbnail for P1010434.JPG]
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Jesse

Pardon the obvious (perhaps), but... how do the pieces fit together? It seems like two left sides and no right side. Perhaps half of the bottom and half of the top?

Confused!
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Ha! Yes I can see how this would be confusing. It's not obvious at all really because the form on the left was an idea I've already discarded. I might use it just to practice slip casting, but it may (probably will) go straight into the archives. The form on the right is the first one I've pulled off that's consistent with the 4 piece idea I posted images of a little while back. The idea is to see if I can even pull the technique off before making more forms.
 
Posts: 18
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
HI
I'm new and just started playing with the rocket stoves. And I apologies if I am butting in. I seen your cardboard forms, nice. You mention they are not sturdy enough. One thing I do know is fiberglass and concrete. Have you thought of using the cardboard forms to make fiberglass forms. It would be a simple process of coating them release agent then with cloth and resin. (Maybe fiberglass resin is not in keeping with the forum but they would be reusable) also when placing the concrete would it go easier if you would take a electric sander and put around on the form to "vibrate" the concrete in place. Just some thoughts.
I'll be watching with interest.
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Jesse, et al

This afternoon I assembled the burn tunnel form (interior / Inside form) for my first rocket stove, thanks to tips from Matt - broaudio - on YouTube. I also glued the walls of the outside form. I used a jigsaw to cut the inside forms from hardybacker board from Home Depot (3' x 5', $10) using a glue gun to assemble the forms. I might put up pictures tomorrow ciao
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi Everybody

Here are my design files. Perhaps you can use them as well for your project. I can email you the PPT file if you send me a message.

K.
My-Rocket-Stove-Design.JPG
My-Rocket-Stove-Design
My-Rocket-Stove-Design
My-Rocket-Stove-Design-Burn-Tunnel-Shapes-Layout.JPG
My-Rocket-Stove-Design-Burn-Tunnel-Shapes-Layout
My-Rocket-Stove-Design-Burn-Tunnel-Shapes-Layout
My-Rocket-Stove-Design-Burn-Tunnel-Cutouts.JPG
[Thumbnail for My-Rocket-Stove-Design-Burn-Tunnel-Cutouts.JPG]
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
The slip casting piece of the experiment has been going for about a week and a half now. Not much progress has been made.
P1010436.JPG
I poured fire clay and perlite slip into this form
I poured fire clay and perlite slip into this form
P1010456.JPG
Over a week later, the clay mix still hasn't released from the plaster.
Over a week later, the clay mix still hasn't released from the plaster.
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Of the things I've tried thus far, I think the slip casting thing has some real merit. There are still lots of kinks to work out. At this rate if I wait to figure it out, It'll be next winter at the earliest, before there's heat coming from my basement. I think the thing to do is to get A core completed and gain some experience sooner rather than later. The slip cast idea will probably become a thread unto itself.

Funny how this is shaping up. The idea I appear to be landing on for a good and inexpensive core "right now" is cobbish in a wooden box (touché Paul)...

At any rate, it's time to start making wooden boxes and filling them with the stuff of a RMH. The "modular" part of the project is something I know I can pull off. Here's a little different view of the overall layout as it stands.
slipcastcore-modularity.jpg
slip cast core-modularity
slip cast core-modularity
slipcastcore-unassembled.jpg
slip cast core-unassembled
slip cast core-unassembled
slipcastcore-assembled.jpg
slipcastcore-assembled
slipcastcore-assembled
 
pollinator
Posts: 4154
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
61
hugelkultur fungi books wofati solar woodworking
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Jesse Biggs :I really like your whole project, and the direction it is headed in ! you totally get the idea that the mass serves us best as a sculpted piece of
built-in-furnature! Just a reminder that the extra elbow in the 180 degree turn at the end will reduce the total amount of Bench you can have by 5' and you
should have a clean out at That Location ! For the Craft ! Big Al
 
Kevin Prata
Posts: 61
Location: Nyack, NY
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
That's a beautiful design! I Like it!
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
It'll probably undergo several more iterations, but thank you. Here are some views from the other side. Allen, the overall run is about 25' right now, and it's an 8" system so I'm thinking it's still well within range. I appreciate your pointing out possible sticking points so I don't screw things up too bad, so please flag away.
slipcastcore-backside.jpg
slipcastcore-backside
slipcastcore-backside
slipcastcore-backsideI.jpg
slipcastcore-backsidel
slipcastcore-backsidel
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Let the box making begin!
P1010458.JPG
[Thumbnail for P1010458.JPG]
P1010460.JPG
Yep it's on skids
Yep it's on skids
 
Cindy Mathieu
Posts: 245
Location: near Houston, TX; zone 8b
3
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Your craftsmanship is gorgeous!
 
allen lumley
pollinator
Posts: 4154
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
61
hugelkultur fungi books wofati solar woodworking
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
His photography isn't to shabby ether, you go ! Jesse !! Big AL
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks for sharing that stuff Max. Got the wheels turning.
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
By way of an update...
P1010486.JPG
[Thumbnail for P1010486.JPG]
P1010490.JPG
[Thumbnail for P1010490.JPG]
P1010502.jpg
[Thumbnail for P1010502.jpg]
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
This Saturday a few folks are coming to help me fill the benches with gravel so we're now in full fledged "get it done" mode.

Some pics:
P1010506.JPG
[Thumbnail for P1010506.JPG]
P1010507.JPG
[Thumbnail for P1010507.JPG]
P1010521.JPG
[Thumbnail for P1010521.JPG]
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
more:
P1010524.JPG
the manifold
the manifold
P1010531.JPG
work station complete with brooder lamp
work station complete with brooder lamp
P1010538.JPG
[Thumbnail for P1010538.JPG]
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
and more:
P1010540.JPG
modular bits
modular bits
P1010545.JPG
semi-assembled
semi-assembled
P1010547.JPG
another angle
another angle
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
and one more
P1010548.JPG
[Thumbnail for P1010548.JPG]
 
Dave Woods
Posts: 18
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Care to give up what mix you decide on for your pours?. Looks like your setting a goal for other to reach to
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I ended up using 3 parts perlite to 2 parts fire clay, simple as that. We'll see how it shakes out.
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Some thoughts... I live in suburbia (in an HOA even). I've posted this publicly here and in a couple facebook groups. Some people I don't know yet are coming to help me work on it in a few days. I figure it's a matter of time before "bad guys" get wind of what I've done. If I can just get enough time to compare heating bills before and after + prove that it's completely clean and safe + make it "pinterestable", I might have a fighting chance. Other people might even want to do something similar. Probably not, but maybe. A guy can dream right?
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
There were folks here 2 days ago helping me get things buttoned up. The system is still quite cold and wet and I think some optimization needs to happen, but we did burn a fire in it for about 1/2 an hour. Here are some pics of what happened over the weekend.

You'll notice there's a "fancy" corrugated metal roof wall behind the bench. while looking for the cheapest metal roofing I could find for shelter in my chicken paddocks, I decided 50 cents a square foot was a great price for a finish material and might help me achieve the man cave ambience I'm going for. Also, I figured if I didn't get that bit of the wall finished in some way, there was a real good chance it would NEVER get finished.

P1010550.JPG
pre-pebbles
pre-pebbles
P1010553.JPG
cleanout #1
cleanout #1
P1010554.JPG
kid tunnel
kid tunnel
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
more pics:

P1010557.JPG
cleanout #2
cleanout #2
P1010564.JPG
core meets black stove pipe
core meets black stove pipe
P1010567.JPG
pebbles going in
pebbles going in
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
more:

P1010578.JPG
core and full riser in place
core and full riser in place
P1010590.JPG
barrel on
barrel on
P1010593.jpg
[Thumbnail for P1010593.jpg]
 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
a couple more details:

P1010592.JPG
what you see when you come down the stairs
what you see when you come down the stairs
P1010594.JPG
hand prints after a burn
hand prints after a burn
P1010596.jpg
stadium seating return... warm butts, backs, and feet
stadium seating return... warm butts, backs, and feet
 
master steward
Posts: 32708
Location: missoula, montana (zone 4)
hugelkultur trees chicken wofati bee woodworking
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
You are using pebbles and not sand, right?

It sounds like you went with cobbish. Be prepared for cracks and to seal up those cracks with more cobbish.

 
Jesse Biggs
gardener
Posts: 213
Location: 40N 112W On the Edge Between the High Steppe and High Desert
52
hugelkultur forest garden tiny house wofati solar woodworking greening the desert
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
It's gravel, but it's pretty small stuff. I found a killer deal on 15 tons. Over time I plan on getting lots of bigger stones buried in there.

I've already had a pretty massive failure in the cobbish riser, which I'm currently fixing. Photos to come. Got a cold snap coming so there's incentive to get this thing cooking.

 
Posts: 73
Location: North Carolina, near Raleigh
4
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Awesome project Jesse ! Love it
 
Posts: 126
Location: Springfield, mo
2
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Jesse-
I've been following your project since the first postings you made. I was intrigued by your use of a mold to cast a core.
I am thrilled to see your work coming to completion. It is a beautiful unique and simple design. I especially like the modular nature of your system.
Will there be some kind of finish coating on top of the pebbles?

A thought about the riser. I'm not sure but the thought occurs to me that using fiberglass mat (or perhaps fiberglass cloth) which is used in fiberglass auto body work (one of my lines of work) would work to reinforce/wrap the cob on the riser. The mat type is kinda like a denser version of those cheap furnace filters i.e. random strands. The cloth type is an actual woven strand material and much stronger. I'm not sure of the heat tolerance of those materials for use on the inside layer of the riser, but I think it's pretty high. It might be cheaper than other alternatives.

I was just reading the shipable core thread when the fiberglass thought popped into my head, and after seeing your post there I think you might be a top contender for a cheap lightweight design. Looking forward to more progress on that front.
gift
 
Rocket Mass Heater Manual
will be released to subscribers in: soon!
reply
    Bookmark Topic Watch Topic
  • New Topic