William Burris

I'm looking for source of 36 x 48 Ceramic Fiber Board near SE Michigan.  Because shipping this product is so expensive I am looking for something within a reasonable driving distance, ideally less than about 200 miles.

Hi Thomas,

I noticed you used 7" (shop) and 6" (studio) when you converted your 8" J-Tubes.

Do the 7 inch and 6 inch relate to Peter van den Berg's design dimensions https://batchrocket.eu/en/building?

The Cross Sectional Areas for 6, 7, and 8 inch are 28.28, 38.48, and 50.27 square inches respectively.

Are the reduced size of the batch boxs you built based on your BTU (kWh) requirements,  a physical design (size) constraint, or some other factor?

Thanks

Hi Thomas,

Great information.  Thank you.

I'm thinking I may start by building a J, but building it to minimize issues of converting to a Batch Rocket when/if I do convert.

I've been looking for a good comprehensive discussion/article/thread on the pros and cons of batch vs. J-channel on the Permies site and elsewhere, but have not found one.  If anyone knows of a source for this information please share, or maybe we can create the information in this thread.

Curious about:
- efficency (fuel consumption)
- build cost
- build complexity
- long term maintenance (cost and complexity)
- minimum realistic/efficent system size

Also interested in conversion of J-channel designs to Batch rockets.

I'm delighted at all of the activity on this post since my original post. Because fall is quickly transitioning to winter here, I am building my wood shelter pretty much as described in the first post of this topic, but slightly downsized, 8x16 instead of 10x16, because I had some 8 foot landscape timbers already.  I have the base built and most of the component fabricated.  I'll post pictures soon.  

I do have a question for folks using log splitters.  I there I point where you transition to an ax for smaller splits to feed your RMH, or do you just keep splitting with the log splitter?

Jay - thanks for the great post.  I may use rigid panels for the roof based on your and other's comments.  I have certainly had any tarp failures with my boat covers over the years.  I think your 5th point is unfortunately a real risk and I believe we will see it here.  When people and their families are cold and hungry they do stuff. Gardens will be at risk too.

Replying to multiple messages:

Thomas - wood is multiple types, maple, some oak, hackberry/mulberry, some pine.  Most was green when cut, but has been was just bucked up, still rounds.  Mostly 16" length, some long limbs/poles still need to be bucked.  Would love to build a proper shed or barn, but I live in suburban  township with a tough zoning board.  That is the reason for a rather light minimal structure that I can disassemble and move if the township doesn't like my structure.  I like you ideas of long overhangs and attention to orientation of the structure and a steeper pitch roof.  I'm OK with replacing the poly tarps as they fail for initial cost and ease of disassembly if it becomes necessary.  I could replace polytarp with rigid roofing in the future.


Glenn - We seldom get heavy snow here, and I can drag it off the roof with a push broom if is starts to accumulate.  The idea of the side curtains was to limit precipitation from blowing into wood pile, but lower wall on windward side could also mitigate water intrusion.  My design have the high side (gable end) facing south.

Mike - Yeah, a solar wood kiln was kind of what I had in mind.  I considered a hoop house design, but I'm concerned that may not be acceptable the neighbors.  I like my "roman shade" side curtain idea for a number of reasons. I can play around and channel air flow from all 4 sides by raising/lowering curtains various amounts and as mentioned above limit rain and snow from blowing in.  The design is not going to be real tight, there will be a lot of infiltration so I'm not worried about trapping moisture.  That said, I don't know how good of a solar wood kiln it would be, but I have a sailboat I cover with a blue poly tarp and I'm always amazed how warm it is onboard in the winter, and it is a very leaky cover.

Jack - thanks for the heads up on high temperature and case hardening I would never have considered that.  I think the design will have enough ventilation to avoid that, but I will definitely monitor that.  With the curtains I can make adjustments to vent excess heat pretty easily, or I could incorporate some paraffin vent openers to automate venting.  I'm definitely going to be splitting my rounds as I load the wood shed.  

Ben - I think corrugated panels could work well, but check performance at the 150 degree f temperature you mentioned.  With a roof over the pile I don't think weeds would be much of a problem, not much water or light.  You could also have a shallow French drain around the perimeter to channel water away, this is something I am considering.

Treavor - your post is very encouraging.  I have a bad habit of over designing stuff, and lots of times not much is gained by the additional complexity and cost.  I have to employ the KISS approach more!  Thanks for posting the picture.

Michael - great idea and very simple.  Reminds me of the corn cribs on my grandfather's farm when I was growing up.  Cobbed corn loaded into a huge slatted crib to air dry - a tried and true method of storing stuff and keeping it dry.


 

Weather is changing here in Michigan so I'm kicking the can down the road for building a RMH until next summer.  This is largely due to the fact I do not have a good supply of seasoned firewood.  I am planning a facility to dry wood I already have but is poorly stored, some of which is probably beyond saving.  I'm looking for sage advise I am sure I can find here.

My idea is to build a greenhouse like structure:
 - dimension approximately 10 ft x 16 ft
 - 2 x 4 framing kind of like a ranch house, 6.5 to 7 foot side walls, 6/12 pitch roof
 - built on platform 6 to 8 inches above grade, decked with 2x6s, space about 4" apart to facilitate airflow from below
 - lengthwise divided into 4 - 4 foot modules/partitions cover with fencing to contain firewood
 - covered with 10 mil, clear polyethylene tarps (poly tarps)
   * roof a single tarp
   * ends - one tarp each end - gables possibly open for ventilation and to get rid of moisture
   * side curtains about - two each side 8 feet wide (facing east and west -  by the way  we have prevailing westerly winds here).  Curtains would be roman shade type that can be raised and lowered depending on conditions.


Not sure if this is overkill.  I know a lot of people say just cover from above and maximize air flow through the pile.  My though is that if you can heat the pile with solar radiation at times this could be useful, side curtains could eliminate blown in rain and snow when during storms.

Your input and advice please.

Thank you

Hi Thomas,
Wow, thanks for that information. I never considered negative pressure!  QUESTION- Does this negative pressure exists throughout the whole system (from feed to top of chimney).  I assume it does, so if there are any tiny gaps in the masonry joints of my bench bell they should not leak either once draft is established. My masonry skills are less than perfect and I have/had a real concern about leaks.  Also, I know cracks in clay/sand mortar can occur over time.

I've done quite a bit of searching of the forum on this topic.  It seems there are a lot of different possible ways of doing it.

The build I'm envisioning is based on Matt Walker's SuperHot J - 8 inch.

I plan on using open head 55 gallon drums.  The top of the riser of the 8 inch SuperHot J is about 35 inches above the base, so I will need more than one barrel. I plan on having the bottom barrel extend down even with the bottom of the burn tunnel.  The bottom barrel (probably less than a full barrel) will have two rectangular cutouts, one that slips over the burn tunnel, the other for the attachment of a transition section leading into a bench bell.  I'll probably have the flue exit the lower half of the bell adjacent to the drums to assist in generating draft in the chimney.  Burn tunnel and bell will be clay brick set with clay sand mortar, the bench bell top will be some kind flat stone or cast concrete.

I would like the option of doing some cooking on top of the drum as well as heating water for additional humidity, two full drums would be too high that - 68 inches.  A drum and a half would be 51 inches, still a little high, but probably OK, and it would give me about 15 or 16 inches of clearance above the top of the riser.

So finally I'm getting to my questions on joining the barrels!

- for the top full barrel I'm thinking I will use it right side up - using the removable head as the cooking surface, held in place with a barrel band and ceramic fiber gasket. Should I saturate the gasket with clay slip before I clamp it, or is that overkill?  I also plan on cutting out the bottom of the top barrel about 1 1/2 inches in from the outer diameter,  leaving a hole about 21 inches in diameter, the outside diameter of the riser is 10 inches, so I will have 5 1/2 inch clearance from the riser all around if I center things perfectly.

- for the lower half barrel I'm thinking about using the the bottom half of the barrel, flipping it upside down, cutting out the bottom as described above for the top barrel.  I could then place a ceramic fiber rope between the barrels.  Then clamp the two barrels together with a barrel band and gasket, possibly saturated with clay slip.

Does this seem like a reasonable plan?  Do you see problems or have concerns?  If you have suggestion for a better solution, please let me know.

Thanks.