Eric, i like the side plenum with the pipe. Obviously not the first time i see it.

But i like it


You were stating about your burn tunnel being a smidge too high. But you didn't account for the P channel overhang down! Which would make it perfect.

and,

https://www.harborfreight.com/7-in-segmented-dry-cut-diamond-blade-for-masonry-68883.html

Hey Satamax. (Edited to correct your name, so sorry) My burn tunnel is the opposite a touch too short. The plans call for 7 by 7.5 inches and I have 6.5 by 7.5 inches.


I don't understand what this p channel is that you speak of. Could you please elaborate?

Here ya go!

Hi Eric;  Not sure what max was referring to but here is my P channel  (named for peter Berg the inventor) It extends apx 1/4" below your burn tunnel roof . Allows fresh cooler air in and creates a turbulence in the air flow ,  combine this with a Trip wire built in to a roof brick further down the tunnel roof and you will get the optimum burn pattern for a J tube.

Ok I understand the channel. What do you mean by a trip wire?

I don't have one myself but a trip wire is )  not a wire but a notch cut into a roof brick apx 2/3 of the way to the riser (i think)  changes the gas flow.  I'll check my book to see if I can find more info for you.  Try searching here on permies for it , I know there have been posts about it.

Try this,   https://permies.com/t/60402/channel-explain

My neighbor invented something similar for his L shaped rocket cook stove.  He puts a piece of 3/4 black iron pipe inside the wood feed with a 90 fitting the end.  Says it runs better that way.  The guys never seen the internet so it's interesting how people can come up with the same ideas on different ends of the world.

I went to weld everything together today.......what a disaster

I marked everything and ground all the paint off of the areas to be welded





Using my scrap barrel as a bench, I tack welded everything in place



That's when everything went to hell.

I first tried mig welding it.  I kept blowing holes through the 8 inch pipe no matter what I did.  Then I tried oxy acetylene welding it.  That was working fine, but taking FOREVER.

I decided to try brazing it to see what would happen.  Worked AWESOME!  I wish I would have went straight for brazing.  The braze flowed perfect.



I brazed inside and out, the hardest part was patching all the holes I made with the welder.... uhg



Cut out the pipe and the ground it smooth



Mocked up



Pictures of the transition

May I ask for some opinions of the exhaust tubing through the bench?  The book says for an 8 inch system, the max is 50 feet of horizontal tubing.  Subtract 5 feet for each 90 and if your exhaust flue pipe is next to the barrel and mostly inside you can add back 10 feet.  

The way I have this mocked up, I have about 30 feet of horizontal pipe.  I have 5  "90's"  So that puts me at 55 feet.  

My intended exhaust flue pipe is not super close the barrel, about 20 inches away, but will stay inside the building and heated area for 14.5 feet before exiting the roof.   The ridgeline of the roof is about 17 feet, so I will need probably 5-6 feet out in the cold exterior temperatures to get 2 feet higher then the peak.

Do you think this is too much horizontal to draft well and be reliable?  Should I reduce it's length?

Here's some general pictures

I'm using a 90 to sort of step down out of the barrel so that there will be plenty of a gap to the top of the bench to prevent overheating the top.  I did NOT figure this 90 into the calculation for feet of ducting because it doesn't change the direction of the flow really.  Perhaps I should?







Please tell me what you think about the overall length and layout.  I intend to put a "T" into the pipe upward to the roof and use black fireplace pipe, so its really just a rough mockup....

It's comming out good and clean, can't wait to see the finishing

In this pic, get rid of the end elbow, put two T face to face, so there is the opening of the T in line with the tube. That would help you clean the tubes.

In this pic,



I hope the T will come between chimney's elbow, and tube, for cleaning. That would be good practice, also can act as a primer. To light a little fire, to warm the chimney.

Also, it would be good practice to  put a t again, on the next tube exiting the barrel.  to clean the first length easily. And you could bypass the bench temporarily between the two, to warm the chimney again.

I think 55 is a smidge much; Why don't you cut the two end of the bench tubes a bit, so you're perfect?

On the side that makes the 180, I had intended to make the bench all the way to the wall. I'm envisioning leaning up against the wall sitting on the bench with a book and then laying down to take a nap.

In it's current configuration the tee is about 18 inches from the wall. I could shorten each tube 2 foot and be at 51. Would it be too much bench to be built up to the wall with no pipe in it that far?  That's a strange sounding question.  Basically do I have to shorten the bench if I make those pipes shorter or is it ok to have a bench with no pipes in part?  That's why i did the tee plus the 90, because i didn't envision having access to that side for cleaning.

I'm not sure how much cleaning is required in the tubes, but what I had in mind was just using a fishtape for pulling electrical  wires and pulling a brush through.

Well, i would shorten the bench ,and make a wooden stool to finish it to the wall, covering those tho T

You need to clean.

https://permies.com/t/63909/RMH-diagnosis

https://permies.com/t/58540/clean-works-didn-work

I'll go ahead and shorten the bench a bit like you say.

Today I decided I was going to burn off all the paint from my barrels.

I set the green barrel up on 3 fire bricks to allow some air underneath and filled it full of a couple old branchs





This got freakishly hot quick.  The paint started smoking off the barrel.



Then it started to turn black



and then the outside spontaneously caught on fire....



I started burning the bottom section when the fire was ridiculous



Moved everything around and burnt the lid off



I took the lid off and set it on the ground, the ground immediately caught on fire



The key to all this was when it was good and hot, I blasted it with the water hose.  This shocked it enough that every bit of paint just shot right off.  Although a good hot fire helped too.  Even though I'm hitting it with water, you can see the bottom of the barrel is still orange....



This is what the hose did, compared to the paint you still see on the left side that hasn't been hit with water yet.



The whole process of burning the barrels went super quick, like 30 minutes tops, including cutting all the wood.

I had it in my mind I was going to paint the barrel with hightemp paint, but I estimated I would need about 60 dollars worth to do it right with primer and everything.  I opted to just cover it with coconut oil(free and didn't use very much at all), which I'm glad I did because it was a major time saver.  I coated the whole thing and was done in 5 minutes.  If I painted that it would have taken me hours

Finished barrels

I will try to remember that.

Fascinating project. Amazing fabrication skills too. Creating the joint between the barrel and the stovepipe and getting it welded up up satisfactory, WOW. That is no simple task , and especially feel for you when you started to realize the hard work of cutting it out properly was in peril because of the difficulty welding thin gauge metal. Congratulations this is so encouraging. I'm av\idly following along.
Brian

Thanks for the kind words Brian. I used to be part of a machinist forum, we would do step by step builds in our own thread until we had a completed engine and I really enjoyed that process.  I thought I would try it on this forum.  I was hesitant will all the pictures, some people hate that.

Progress is going to slow for a bit, I have a 4 day  conference in Dallas to go to tomorrow and then I will be back for 2 days before leaving again for another 3 day conference.  I've ordered the insulation and stove gaskets and they should get here while I'm away.

Eric Hammond wrote:Thanks for the kind words Brian.

You are most welcome Eric. I have been here a few years, during a very difficult time in my life. Illness has kept me from doing my projects. I hope I'm surfacing now and and able again to build the things that made me feel proud and happy for decades. Your build is so very encouraging for me, thank you!

Eric Hammond wrote:I used to be part of a machinist forum, we would do step by step builds in our own thread until we had a completed engine and I really enjoyed that process.  I thought I would try it on this forum.  I was hesitant will all the pictures, some people hate that.

Progress is going to slow for a bit, I have a 4 day  conference in Dallas to go to tomorrow and then I will be back for 2 days before leaving again for another 3 day conference.  I've ordered the insulation and stove gaskets and they should get here while I'm away.

Yes I agree, the step by step method is very helpful for those of us that may wish to reproduce a similar build. I only wish I had more to offer, than praise. We had a rocket stove workshop here at our homestead in northern New Mexico several years ago, that's about it on what I knew before your project. The detail you provide is outstanding for mechanically-minded folks such as myself.
Brian

Hi Eric,
  I just found your thread last night and have been reading/looking through it.  VERY insightful and helpful.  I am kind of in a similar situation, I wanted to install a RMH last winter, but time got away and decided to do it this summer. However, I am still at zero progress (other than supply gathering).  I a m going with a 6" system from Ernie and Erica and plan to do it "by the book".  It is for an existing brick floored buildout with  no heat- kids play room.  We have relied on space heaters for 10 years.  We live near Tacoma, WA.   I am a stay at mom with 4 kids and have no "shop skills" (life science was my field of study/work).  My husband is a bit more handy, but works full time.
 I planned to go with a firebrick riser wrapped in rock wool insulation.  I salvaged firebrick, but have no 1/2 (split).  I found light kiln brick for a decent price, but now read that using heavy for the burn tunnel and light for the riser may cause a problem.  We have no torches or welding stuff, so I was planning on going with a brick manifold.    Anyways, it is nearly August and still ground zero.  I am petrified and frozen to move forward.  2 kids are at camp next week, so maybe can...start.
ANYWAYS- I appreciate your posts and may have to pick your brain on occaision.  THANKS! Staci

Staci Kopcha wrote:Hi Eric,
  I just found your thread last night and have been reading/looking through it.  VERY insightful and helpful.  I am kind of in a similar situation, I wanted to install a RMH last winter, but time got away and decided to do it this summer. However, I am still at zero progress (other than supply gathering).  I a m going with a 6" system from Ernie and Erica and plan to do it "by the book".  It is for an existing brick floored buildout with  no heat- kids play room.  We have relied on space heaters for 10 years.  We live near Tacoma, WA.   I am a stay at mom with 4 kids and have no "shop skills" (life science was my field of study/work).  My husband is a bit more handy, but works full time.
 I planned to go with a firebrick riser wrapped in rock wool insulation.  I salvaged firebrick, but have no 1/2 (split).  I found light kiln brick for a decent price, but now read that using heavy for the burn tunnel and light for the riser may cause a problem.  We have no torches or welding stuff, so I was planning on going with a brick manifold.    Anyways, it is nearly August and still ground zero.  I am petrified and frozen to move forward.  2 kids are at camp next week, so maybe can...start.
ANYWAYS- I appreciate your posts and may have to pick your brain on occaision.  THANKS! Staci

Hey Staci. Obviously I'm no expert, but the book clearly stated that light insulated brick for a heat riser was a suitable alternative to other insulation forms, so I'm surprised you found information that said that was an issue.  I was going to go that route but could not source any locally.

I think a brick manifold is a great idea.  The cost of bricks for me was prohibitive and I really enjoy metal working.  If designed right you could have a huge area for ask collection to maximize the amount of time  between cleanings.

I think I would use as large a pipe I could out of the brick manifold and neck it down to the 6 inch.  Maybe a 10 inch down to an 8 and then down to a 6.  The less restriction in this area, the better from everything I have read.

Also, don't be afraid to start.  Just do it!  Nothing is ever permanent and we all screw up, there's nothing that can't be solved with time and money......

I'm the worst about getting stuck in analysis paralysis, I think way way way  too much and worry.  Sometimes you have to just do.  Beer or wine helps.

Uhhg finally back from some conferences.  Made a little more progress.  I ordered my woodstove gaskets for the lid and barrel, plus the insulation.  I had previously measured the barrel lid gasket area with a crude method, a 1/2 inch drill bit fit quite nicely.



So I ordered 1/2 rope gasket for the lid and  1/8 inch flat tape for the barrels.



The channel for the gasket still has some burnt crud inside, this needs to be cleaned out good.  My favorite all around crud cleaning solvent is brake parts cleaner.  I swear by it for everything under the sun.




Filled the channel and wiped it out until the paper towels came out clean. Dries super fast with no residue.



The tube of cement has to be kneaded well. I went ahead and dobbed some all around the rim and spread it out.  Adding and extra amount where the rope will start and stop.







The rope was then laid into place pressing it into the channel, paying special attention to not stretch it.







Trim the hairs and voila, 1 complete lid

The same process was repeated to glue the 1/8 inch flat gasket which will seal the barrels to each other

Now for insulation of the heat riser, I went with ceramic fiber blanket insulation.  It was listed in the book as really the best thing you can use.  For what its worth I COMPLETELY REGRETthis decision.  Not only is it expensive, It's probably one of the worst materials I've dealt with.  It feels like its going to give you cancer.  Have you ever dealt with fiberglass insulation?  Think of this as about 5 times as bad as that experience.  Way worse itch, plan on throwing your clothes away when your done, and wear a respirator.....unfortunately the little fibers float around your house so its not going to save you in the long run.....

It started with me receiving a nice package from UPS



This is the 1 inch this blanket



I wanted to place the manifold barrel on and trace its location onto the bricks so that I knew my boundaries as far as where the insulation goes.  The wanted at least 4 inches between the barrel and the heat riser.  I've got plenty of space, even factoring in the  inch blanket







I unrolled a bit of blanket to cut my first piece, I cut it at 42 inches, this should have gave me just a touch of overlap...it ended up just a touch short actually.  The blanket cuts very easy with a razor knife.  I use a board for a straight edge, same thing I use for fiberglass insulation





After MANY unsuccessful attempts of holding the blanket up, I resorted to using a pull type strap.....this strap is ruined now filled with all the fibers.  This couldn't be a two person job because I was unwilling to let anyone else expose themselves to this wicked material



These little pieces are constantly falling on your skin and irritating it and breathing the tiny fibers


I finished wiring up the first piece



The wire I used came from the farm store and is simply just called "tie wire"   mechanics wire would work as well

The process I used for tying the wire was as follows

Pull the wire as tight as you can by hand and twist it up



Grab any side that needs tensioned  tighter with your needle nose



Turn the pliers clockwise to effectively shorten the wire and make it tighter





Then just trim off the excess

i cut the next swatch of blanket 1.5 inches longer since my first piece barely made the cut (awful pun intended)  This piece ended up way wayyy too short.





I had to trim it a bit to clear my lines and Make it fit the bricks tight in the front.



I added a small bit to cover up my error



Lastly, they said to cover it up with a wire so that it didn't get damaged during cleaning, I had some 4 foot chicken wire, so I just used that



The amount of bad stuff that comes off this material is rediculous

very helpful

Its about time I update the money involved in this project so far.  

Initially I spent $138.52 on firebrick at ACME brick.
I went back and spent another $49.22 on more bricks and at 15 lb bucket of refractory cement
The cost of the fireclay $9.89
The mortar from lowes $4.28
The perlite from MFA  $20.00
The 2 55 gallon barrels $40.00
One section of black flue pipe $10.00
All the flue pipe from lowes $195.55
Wood stove gaskets  $33.58
Ceramic Fiber blanket  $99
Tie Wire  $4.59

Total so far roughly:  $ 604.63 dollars........that's rough to see.

Items I had on hand but would assign a value to

Chicken wire  $5 dollars worth
Fuel costs for torches and welding equipment, probably close to $30
Cutting discs/grinding wheels $7
Beer total $30

Misc $72 dollars

So realistically I'm in this around $675 ish so far.   It does hurt, but I bet I spent $800 on propane last year and it was a very mild winter and my propane heater was $900 dollars itself.  I have ten acres myself, but 30 combined with my neighbors that I could harvest from for wood and have been considering my options for establishing coppice wood.  This is a project that potentially could pay for itself the first year, but definitely by the second.

and to be honest, I was going to drink the beer anyway....

For bolting my 2 barrels together I thought I would add a little bit of my personality to it.  I picked up some wrenches from the pawn shop for a buck.



I heated and bent those wrenches to a 90 degree angle





Marked the barrel and spaced evenly around with 3 attaching points



Tack welded into place



Welded the first wrench



It went so good I got a little careless on the second wrench and blew two holes through the barrel, I had to patch them up with more weld.  After that I was very careful not to do that again.



Here's the general idea



3 bolts and the barrels will be attached together.  I will probably use some high temp silicone just to be sure of a complete seal and since this section won't come apart very often.

It was time to secure the lower barrel in place.  I had bought a 15 lb tub of fireplace mortar to do this.  Talking to the guys at ACME brick, they said this is a refractory mortar that can be used to fill large gaps and is super popular with outdoor oven makers.  The internet had this type of stuff way cheaper, but I went ahead and purchased it from ACME because they had used this specific product and recommended it.



Nasty looking inside and needs stirred up





I went ahead and used brake parts cleaner to clean the oil off the edges of the barrel to be mortared so I wouldn't have any adhesion issues



Using a sponge and a bucket of water that's been sitting around for weeks and starting to smell pretty funky, I moistened the bricks around my line drawn.  In my head I thought this would help the mortar adhere to the bricks and keep it from drying too fast having the moisture pulled out of the mortar.  Whether any of this is true, I'm not sure, but it made me feel better.



As you can see in this picture, on one side the barrel doesn't sit fully on the brick, on the other side it did and there ended up being a small gap at the back.  This really isn't an issue and easily filled with the mortar.  It's just odd how it happened.  I think know that when I burnt the paint off the barrels, this one warped a little.  It may have been a better idea to get the paint off the barrel first and then make all my cuts so that I didn't have any warpage issues.  Even the two barrels don't fit together quite as well as they did.   The top barrel really had no issues, but I think all the cuts in the bottom one didn't make it as structurally sound.



I went ahead and started laying down a thick bead of mortar along my line







The barrel was then set down into the mortar.  I cleared a couple spots with my finger to see where the line was.  It took just a touch of shifting to get it exactly where I wanted it.



I then double checked that the barrel was level it all directions





Then smoothed the mortar inside and out with a gloved hand.  I had to add a little in some spots





Manifold barrel is now installed

Eric, what do you plan to put around that?   Because this will never be airtight.

Satamax Antone wrote:Eric, what do you plan to put around that?   Because this will never be airtight.

I intended another layer, but that's it. This is the exact procedure from page 84.  Why do you think it will not work?

Expansion and contraction of teh metal with heat.

Do you have another suggestion? Im definitely open to it.
Otherwise I'm going to have to just roll with what the book says.  I understand what you mean about expansion, but the way the barrel fits inside of a joint in mortar seems equivalent to a labyrinth seal, which are very effective for such primitive technology.  I would think if there was any leak ash buildup should seal it completely very shortly.   The length of flue could play a roll as well. If the draft was too strong perhaps air could be pulled by venturi effect through the seal, but if the draft isn't super strong I would think the hot expanding gasses inside the barrel could never let outside air in.

I also don't see a reason why the book would print a technique that doesn't work, but again, I have no idea what I'm doing

Well, i haven't read this book. To me, i would fit dôme rockwool, or superwool around the joint you created. Then bricks or mud around. On, may be 4" height.

thank you for the thread, particularly for making it pic heavy, haven't studied much about rmh tech for years and looking at maybe building a system this fall/winter, definitely good to see some pics and the process, will be following along anxiously

Hi Eric,
  I have been working on my own system.  I have the core (J-unit) built, pipes roughly laid out, and am currently struggling with a brick manifold.
Have you began cob work yet?  I am anxious to see the start of cobbing the burn unit.  I will keep checking for posts.
Thanks!!!
Staci

Staci Kopcha wrote:Hi Eric,
  I have been working on my own system.  I have the core (J-unit) built, pipes roughly laid out, and am currently struggling with a brick manifold.
Have you began cob work yet?  I am anxious to see the start of cobbing the burn unit.  I will keep checking for posts.
Thanks!!!
Staci

Progress has been slow!  I had to go back to work, bleh....between work, the homestead and the new baby life has been difficult.  I've made a bit more progress but no cobbing yet!

So its about time to update a little progress.  I did quite a bit of work on the piping for the bench.  Based on Sam's last post he had me worried about air leaks.......and far too much so, I went way overkill on putting the pipes together.  Let me show you what I did.

Every joint, I used my super awesome silicone 9000, screwed them together, siliconed the screws and taped each joint











Every section gets 2-3 screws.

Then every joint got taped.  EVERY joint.  Be very careful with the tape, its super sharp!  I cut myself several times.





Here's sort of the layout I've followed.  I made sure the seams on my long pipes are toward the top to prevent condensation from leaking out of the pipes and taped those joints as well

A couple of the tools that made the whole pipe process easier...tin snips which I already had for trimming the pipe



I purchased the crimping tool  It was 20 dollars and works awesome, worth every penny and makes a professional looking joint.









I really like that tool.