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!!! The RMH Builders guide build-pic heavy  RSS feed

 
Posts: 208
Location: SW Missouri
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Hey guys, Eric Hammond here.  When building my house I've always designed it to have a rocket mass heater.  I had purchased the Ianto book, and frankly found it quite poor on information and not a valuable asset.  After posting here on a discussion about shippable rocket cores, someone had pointed me to ernie and erica's book(sorry I can't remember your name and I'm too lazy to look it up).  This book was perfect for me.  I read it all winter and now that its July, I'm worried as hell about winter!  I read the book cover to cover and encourage you to do the same.  Please purchase the book The Rocket Mass Heater Builders Guide  Read its entirety and then proceed to build.

This will be a step by step build from how I perceived the instructions in the book to go, plus all of my mistakes.  I am in SW Missouri so prices may be different if your area.

First was sourcing the fire brick and building a mock-up to see how it was going to sit in the house.  I'm going to build a bench that will become the kitchen table/dining area.  It's located in the SE corner of my shop house, It will be built on 4 inches of fiber reinforced concrete.

The book did not list a fire brick count.  I counted bricks from the pictures listed to get the amount I needed to purchase.  I think it was close, but not quite accurate.  By my count in the book I needed 56 full size bricks and 28 half bricks/splits.  I purchased 58 full size fire brick but I think I really need 32 splits.  I haven't finished my heat riser yet, but I think it's going to come out short.  I purchased the firebrick from ACME brick in Springfield MO on East Battlefield.  Both the full size brick and splits were $1.49 a piece.  This equates to $138.52 with tax. The correct total of bricks ends up being 56 full size and 34 splits, two to cover up the burn tunnel after completion.  You might consider two extra full size bricks to practice cutting!

Here's the mock-up in the area where the RMH will be:



I'm going to stop here and see if the images show up, and then I will continue!

 
Eric Hammond
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They had refractory thin set at Acme brick, but it was 77 dollars for 50lbs and that seemed a bit steep.  In the book, they mention clay slip made from fireclay as a great alternative to regular mortar, especially if your using new firebrick that the dimensions are uniform.  There's a place called L+R in Nixa on main street that supplies clay for all the pottery shops in SW Missouri. I went in there like a moron and said " I need fire clay whatever that means and 25 lbs of it"  They straightened me out and fixed me up.  They sold me 25 pounds of something called Hawthorn 35. It's a Missouri based fireclay.  Cost with tax was $9.89 for 25 lbs.  I've never made clay slip.  My sister a potter, recommended 2 gallons of water for the 25 lbs of clay.  I used a paddle wheel in a 5 gallon bucket. It turned out awesome.





This made about 2.5 gallons of clay slip.  I was worried at first this wouldn't be enough, but I now think it will be
 
Eric Hammond
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It's suggested in the book to insulate underneath the burn chamber, regardless of what surface the heater is to be built upon.   I believe this is to keep the burn chamber as hot as possible for the most efficient burn.  They recommend clay stabilized perlite.  I sourced the perlite from the local MFA(feed store for farmers).  They sold me 4 cubic feet for $20.  Came in a large bag



Looks like this inside



I added a bit to a 5 gallon bucket and mixed in the fireclay slip to play with some of the materials I'm just not familiar with.  It makes a really cool substance.  If you squeeze it together it holds shape, but also breaks apart easily.  I mixed enough slip to make it brownish.




 
Eric Hammond
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With a little help from the wife I laid out right where the base layer/pad needed to be.  The barrel, needs to be 18 inches from the wall if you intend to use a heat shield on the wall.  Helpful tip: the barrel sits on this base layer pad, so if you measure 18+ inches from the edge of the bricks, you will have the correct clearance for the barrel.  I had trouble deciding how I was going to lay down my insulating layer of perlite, I decided to place a layer of random found bricks around my base layer and house the base layer inside of this layer, on top of the insulation.



Puppy help






 
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Eric, your photos are either private, or not visible for people not logged in, in google. Could you fix that please?
 
Eric Hammond
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I was afraid of that.....it seemed too easy.  They showed up on my phone and computer just fine.  I tweaked google a bit and added all the photos to an album that is public, did that seem to make a difference?  I will hold off posting anymore until I can get this resolved.

Please let me know!
 
Eric Hammond
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It appears with google photos, you must click on each of your photos, click share, then click link, once it provides a link THEN you can copy the images address.  They should be working now correct?  If so I will move on
 
Eric Hammond
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It's worth noting at this point, they STRONGLY recommend laying out all the components for the heater and making your final placement based on where the roof penetration is.  I did not do this.  This is a steel building and my area to come out of the roof can be anywhere in about a 4 foot radius, so the positioning of the roof penetration really isn't critical. 

I had trouble deciding the width of the bench.  I think I'm going to go for 30 inches.  I laid down blue masking tape, the outside edge marks 30 inches to the wall.  I think I will build right up to the wall with no air gap.  Seems like its been done both ways.



As a random fact, in the next picture you can sort of see where we tested various colors of concrete stains before choosing the final color.  Knowing the bench was going to go over it and cover it up, we tested this area.  The concrete stain is soy based called soycrete.  Works really good.




 
Eric Hammond
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At this point liking how it mocked up in relation to the bench


I went ahead and traced the outside of the red bricks with a pencil, keep a sharpener handy(pocket knife) because concrete and brick eat through a pencil.  I then carefully removed the inside firebricks, If I shifted a red one, I could line it up with my outside line.  I then used the pencil to trace the inside.  Once both edges were confirmed I glued each brick down with a few dabs of silicone.  This silicone is the ultimate in silicone technology.  Its for making oil pan gaskets on 7.3 diesels, when it dries you don't even need bolts its so strong....but I suspect any silicone would do.   After all the bricks were glued to the concrete with silicone, I went ahead and caulked the seams to the floor and between each brick to prevent perlite from escaping around the house.







The puppies never stop "helping"
 
Eric Hammond
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The recommended depth for the clay stabilized perlite under the burn chamber was 1-2 inches.  I went ahead and marked the bricks at 2 inches all the way around with a yellow paint pen so I could tell how much I was putting in.  I recommend the stainless steel ruler.  It works great for measuring things less then 14 inches and easier then a tape measure.

I made the clay stabilized perlite a half a 5 gallon bucket at a time. I know crocs went out of style, but they are super comfy, please don't judge.







I went a little overkill.  I actually went about 2.5 inches. This equated to approximately 2.5 full buckets worth.  I still have A LOT of perlite left in my 4 cu ft bag
 
Eric Hammond
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The thing about insulation is that it must not be compacted to work.  Air is the insulation, its the tiny air pockets that allow it to work.  If you placed an R-19 insulation made for a 6 inch wall cavity into a 2x4 wall and squeezed it together, it would not be an R-19 anymore, perhaps even less then an R-13 made for a 2x4 wall.  So in our case, I do not want to compact the perlite.  I placed each block carefully into place, of course the heights do not match up.  Using a dead blow hammer and a level I tapped each block flush with each other and leveled the pad while paying special attention to not compress the material too much, and to keep the gaps between blocks as small as possible.  This is a critical step.  If the foundation is not level, everything built upon it will be of poor quality





I grouted around the entire outside of the firebricks to the red bricks to add support from the outside.  I used a type N mortar found at home improvement stores.  I had a open bag special $3 dollars for 80 pounds.



I had a small gap because my fire bricks were apparently not the correct size I reckon so I filled it with perlite and mortared over the top.






 
Eric Hammond
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To make the bricks dimension-ably stable from the inside, it's recommended to place sand in between the cracks.  This step took a lot of time, I was very particular to get everything packed in great.







All the little grains of sand are different shapes and sizes, so this was taking FOREVER, like over 3 minutes, so I had a wild idea to just brush the type N mortar into it with the dry powder and then I was going to take a water spray bottle, wet the surface and lock all the bricks together.  This didn't work at all. For some reason, even though it was a small consistency, it was lighter and hard to get to penetrate the cracks.



I gave up on that, vacuumed it out with a shop vac and went back to sand.

After I got it done, it DID make for a really firm, really stable building surface that was well insulated from the ground.



It's worth saying that this point, the 4 outside bricks, two on each side, are not really talked about in the book, you could place these incorrectly if you weren't careful.  They are used to support the lower 55 gallon drum.  So if you mock up your bricks without mortar first, you can estimate the middle point of the heat riser and pull out a radius from that center point to figure where the barrel will sit.  The bricks must fall on that arc path to catch the rim of the barrel.
 
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Looking so good so far!
 
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Excellent Job so far Eric, Keep up the good work!
 
Eric Hammond
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The next layer was mocked up without mortar.  The brick closest to me is the only one that has a set dimension.  I want it to cover up that gap I had that I mortared over.  I covered it by maybe a 1/4 inch.  Moving the back brick I could change overall burn tunnel length.  The bricks were centered on the pad left and right and the burn tunnel width was set to 7.5 inches wide by 24 inches long.



Once I found their final place, I again traced the inside and outside with a pencil, then numbered them clockwise, so I wouldn't forget where they go.







 
Eric Hammond
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Each brick was then removed from its place.  I used two buckets to lay the bricks. One bucket, half full of water with a sponge and putty knife in it and the other bucket full of my clay slip.  I had to take the paddle wheel to the clay slip each day to keep it mixed well.  The spot where each brick is intended to lay, I moistened with water from the sponge.  BE CAREFUL not to wipe off your pencil mark....I did this only once.  Per the book each brick was then dipped in the bucket of water.

These next photos show the process, but they were for a different level of bricks so it shows the clay slip being applied to the wrong edge of the brick.



Then dipped in the mortar/clay slip to be laid into place.





I laid A LOT of the bricks in the assembly this way before I changed my method.  This worked just OK, as I got further along I found it easier and better, to use a paint brush(the one I used for the sand) and brush the clay slip onto the surface of the brick I was about to lay and the area where the brick was going to mate to.

In the first layer each brick was laid with slip, tapped together with my dead blow hammer and leveled and plumbed.  If you wait a few minutes the bricks pull enough moisture out of the clay slip that it becomes firm and smooths out easily with your finger.  I smoothed each gap.  Using my scrubby sponge and putty knife, I remove the excess clay while I work to keep it all tiddy.





First layer is complete!

NOW THIS PART IS SUPER IMPORTANT  I did not do this or even think about it until I got to the point of needing to make the first/lower barrel. At some point the lower barrel has to be cut around each of these layers of bricks to fit over the burn tunnel.  Get a piece of paper and measure outside to outside of this layer and height write it down, so that you will easily have your dimensions to cut your barrel with later.  I wish I would have thought of this, but I didn't and now I will have to do math!  Do this for each layer and you will thank yourself!
 
Eric Hammond
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The next layer went just as smoothly.  Mocked everything up, dipped, slipped and set into place, paying special attention that the inside edges form a smooth, uniform edge. Disregard where the outside edges fall.  Again, after this layer is finished, measure outside to outside where the lower barrel will sit.







 
thomas rubino
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Hi Eric;  Looking good.
A few questions ; what is your plan for heating your mass? I know it will be your kitchen table. Are you using piping or a bell design ?  Is this an 8" or 6" system ?  What is your plan on a riser? To use split brick ,insulated brick , full brick ? Are you going with a standard square  riser  or building octagonal?  Have you heard about using ceramic fiber blanket as your riser ? If not investigate the (Five minute riser by pinhead) on the donkey pro boards.  Its quite the invention . My build this summer will use that as a riser and hopefully ceramic fiber boards as my core.  I also will replace my fireclay perlite riser in the greenhouse /studio with a five minute riser.

 
Eric Hammond
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thomas rubino wrote:Hi Eric;  Looking good.
A few questions ; what is your plan for heating your mass? I know it will be your kitchen table. Are you using piping or a bell design ?  Is this an 8" or 6" system ?  What is your plan on a riser? To use split brick ,insulated brick , full brick ? Are you going with a standard square  riser  or building octagonal?  Have you heard about using ceramic fiber blanket as your riser ? If not investigate the (Five minute riser by pinhead) on the donkey pro boards.  Its quite the invention . My build this summer will use that as a riser and hopefully ceramic fiber boards as my core.  I also will replace my fireclay perlite riser in the greenhouse /studio with a five minute riser.



Hey Thomas, good questions.  This is an 8 inch system,  and I intend to use piping inside of the mass.  As far as filling the mass, I'm open for options there, but I'm kind of on a time constraint( I say that but its only July and I have a bit of time before winter hits) I was considering something easy like pea gravel although I know this isn't the best material.  If I could mix the pea gravel with a thicker clay and rid it of most of the air pockets do you think It would make a better mass?  Any suggestions on the fill for the mass?

As far as the heat riser, it is a standard square,  split firebricks that will be wrapped with ceramic fiber blanket.  This is my first build so I'm doing everything by the book(literally Ernie and Erica's book) with very little experimentation.

I am about to purchase the ceramic fire blanket, It's a much better deal if I buy 25 feet, but I don't need that much.   The one I'm looking at is 1 inch thick, 24 inches long and 25 feet long.  Its about 99 dollars.  I estimate I need about 8 feet, so I could but a roll that's 12.5 feet but its about 60-70 dollars.  Would you be interested in splitting a roll to save cost and I send you my left overs?

This is the one I'm looking at:

Fire blanket on Amazon
 
thomas rubino
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Hi Eric;  About your mass.  Pea gravel would be my last choice. Are you encasing this mass with something (ie brick, rock, )?  If so then your job of filling the mass just got easier.  If you build a bench entirely out of cob then your mixture must be just so...  If you encase your mass, lets say with clay brick, now the cob only needs to be mud. Use large rocks placed carefully around and eventually over your already cob covered flue pipe and fill everything around them with a clay type mud, no need for sand, no worries if some plain old dirt gets mixed in, you just want no air pockets. When I built the mass in our studio I had slate , lots of slate,  So I made a Cob and slate lasagna ...layer of slate layer of cob...  I actually mixed cob with sand to do this not realizing it was serious overkill on work.  The brick holds in and hides everything as well as adding more mass to hold heat. Remember rock has a better heat retention than cob, so more rock less cob means less mixing of cob more holding of heat !
 
Eric Hammond
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Good tip about the mass, I do intend on casing it in.  I have tons of limestone here, basically my only rock and more then I could possibly ever need.

The next layer I'm working on consists of the the bridge over the burn tunnel, for this course 2 bricks have to be cut.   That's why I bought 2 extras.  I laid everything out and found my two bricks needed to be trimmed off at 7 1/8 inches. I sketched it out on my bricks.



I do not have the proper equipment to cut bricks.  I'm not going to buy the proper equipment to cut bricks for only two bricks.  I tried it two ways, and both proved successful.

First attempt, I have an angle grinder with a thin metal cutting blade on it.



I clamped the brick to my trailer and scored the brick with the metal cutting blade.  Lots of sparks were coming off and I assumed (incorrectly) that the sparks were from the blade and that I was destroying the blade rather quickly.  So i just scored the surface at this time to conserve the blade( I only have one currently)





The trailer rail is built out of angle iron, I loosened the brick and slid the scored line to match the edge of the angle iron.  I clamped it again, hit it with a hammer, and VOILA!  The wrong end of the brick broke off.....



This was an insightful experience.  As it turns out, the strongest edge of the angle iron to beat against would be the corner edge......I clamped on the wrong side...
 
Eric Hammond
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The next attempt, measured, scored and clamped the brick again, but this time matching my line up with the strongest area of the angle iron as depicted here.



This time, instead of a hammer, I broke out an air hammer.  Basically a pneumatic chisel with interchangeable bits.



I hit my line with the chisel and the brick popped apart, not cleanly, but at least on the correct side of the line this time.



About 20 seconds of careful clean up with the air chisel and I had a pretty straight brick



 
Eric Hammond
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Now that I only had one brick left to cut, I decided to just give er hell with the cut off wheel.



Actually went really well, didn't consume much of the blade, it was apparently the brick that was throwing sparks...



Fully mocked up with cut bricks



Then mortared together





At this point I performed some clean up.  Used a putty knife to scrape all the surfaces and clean with a sponge, vacuumed up little bits with the shop vac and mopped the floor.  Let the whole assembly dry before proceeding.
 
Eric Hammond
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The next course was then mocked up and laid.  This finishes out the full size bricks, and finishes the wood feed completely.  While it looks good, there are a few minor issues.





The wood feed came out short at 14 3/4 inches



As did the height of my burn tunnel at 6 1/2



I was making sure each brick that was laid level and plumb with each other on two planes.  I did that well.





I never checked the third plane of level for how the bricks tipped in and out and it was off!  It never crossed my mind for two reasons.  1) the clay squishes out between the courses of bricks and placing my level on the clay would not give a true reading.  2) I thought by making sure the inside edges of the bricks were flush with each other, that the brick was "square" on it's pad.  This turned out not true.  The chamber started out as 7 inches by 7 1/2 inches NOW the chamber is at 7 x 7 1/4"

I lost a 1/4 inch in just 3 layers of brick!





I didn't immediately panic about this.  But I did start to think If I don't pay better attention for the next 8 courses of brick for my heat riser, I may have a very small opening.  I went ahead and continued on as I was.
 
Eric Hammond
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Starting on the heat riser with the split fire bricks,  I mocked up each layer and mortared them in place again leveling and making sure they were plumb.



The first few layers were not fun, you set the first brick down and line up the edge but it's never in the right spot, requires a bunch of taping around. I found a trick to it.

Mock up each layer so that the inside edges are plumb



Remove two of the bricks



Mark each edge with a pencil this will ensure two of the bricks are laid correctly, so when the final two are placed, there is very little tapping around to get the bricks in the right spot.







Butter each of the side bricks and lay them into place matching your lines up and keeping the inside edge plumb.



Then place the last two

 
Eric Hammond
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After the second layer for the heat riser was laid, I measured the opening of my bricks and found it was now 7 1/4 by 6 7/8.  I decided at this point I could not continue without doing something drastic.  It may have been a mistake, but a decision was made.  I spaced two bricks out on the third layer to make the dimension 7 1/4 by 7 1/4.  You can see my repair here.  I was able to keep this dimension the rest of the way up until the heat riser was finished!



I finished 7 layers as shown in the book, ran out of split bricks, but did not have the overall correct height.  It was only 43 1/4 inches from the floor of the burn tunnel to top of the heat riser.



I had to run back to Springfield and purchase 6 more split fire bricks.  4 for the next level and 2 to control air flow into the wood feed as the stove is running  That brings the correct total of bricks to 56 full size ( 58 if you want to practice cutting) and 34 splits



 
Eric Hammond
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After finishing the 8th layer of splits I now have the heat riser height at 47 3/4, the book calls for 48 or higher.  I'm going to call this good.  I'm afraid if I made it one layer higher it would be tough to remove the barrel for maintenance and clear the ceiling.



After the whole thing has had time to set up and dry, I'm starting to see some cracking in some of the joints.  It looks a little concerning.  The whole structure SEEMS super solid.







At this point I kind of wished I would have ponied up the cash for the actual refractory thin set, because I doubt I would have this problem.  I don't actually suspect IT IS a problem, but it bothers me none the less.  I know deep down, soot and ash will plug the crevices on the inside.  My plan its to take a squirt bottle, re-wet the joints, and paste some thinned out clay slip over the cracks.   What do you guys think about that?



 
thomas rubino
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Hi Eric; Everything is moving along for you.  Add some sand to your slip it will help with the cracking.  Also, do you not have a 55 gal barrel with a removable lid ???  Way way easier to inspect/ clean  if you just pop a lid. removing the barrel should only need happen during a core rebuild.  One of my removable lid barrels I purchased at a farm and ranch store (BIG R) $30.00 the others were located for free by checking county shops , mechanic shops , farmers , someone has that barrel and doesn't need it ... you do.  Only as a last resort would I use a barrel without a removable lid.
 
Eric Hammond
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thomas rubino wrote:Hi Eric; Everything is moving along for you.  Add some sand to your slip it will help with the cracking.  Also, do you not have a 55 gal barrel with a removable lid ???  Way way easier to inspect/ clean  if you just pop a lid. removing the barrel should only need happen during a core rebuild.  One of my removable lid barrels I purchased at a farm and ranch store (BIG R) $30.00 the others were located for free by checking county shops , mechanic shops , farmers , someone has that barrel and doesn't need it ... you do.  Only as a last resort would I use a barrel without a removable lid.



Hey Thomas, let me show you what I've found as far as barrels.  I wanted two barrels with lids like you said.  All I could find locally was TONS of solid barrels or barrels with open tops, no lids, no clamps.  I got on craigslist and found some barrels an hour away advertised with this picture for 20 dollars each.  I kind of thought that was high, but I went ahead and called him to make sure he had two.



I drove up there, but the barrels he had did not match the picture.  They look like this instead:



I went ahead and bought 2, the barrels were used for tomato paste and the lids are galvanized metal.  I can't risk heating up the galvanized and releasing fumes into my house.



The coolest feature is that the top tips in just a bit, and the barrels are made to stack on each other perfectly.



To check how good the barrels fit on each other, I rolled up a few balls of clay and placed them around the edges.









With a thin piece of fireplace gasket I could seal these barrels easily.  My plan was to weld brackets to each barrel and use 3 of these to clamp the barrels together



By using the top barrel upside down I could get rid of the galvanized And utilize my barrels taper.

After I brought them home, my neighbor called me an found these in the trash.



but these lids don't fit because of my barrels tapered top uses a smaller lid.   I would need to purchase another lidless barrel or trade one of my barrels to make it work.  If I welded handles on a barrel I don't think it would be too terrible to take on and off, but I do like the idea of a removable lid, because I'm very very lazy.  What do you think?
 
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I think ensuring the gasket fits correctly is the trickiest part of removing and replacing either a barrel or a lid, and there would not be much difference in the time and care involved. It would just take some more muscle to lift the whole barrel over the riser. Another factor: if you want to closely inspect the riser or other parts or make any repairs, it will be easier to do with the whole barrel off.
 
Glenn Herbert
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You mentioned dimensions being a bit smaller than they should be by the book... I have found that there are the standard commercial firebricks exactly 4 1/2 x 9 x 2 1/2, and a skimpier version about 1/4" smaller in each dimension. At least you don't have a mix of the two - that would be a real hassle to work with (don't ask me how I know).

It's not ideal for the burn tunnel to be only 6 1/2" tall instead of 7", but that is the one place in the system where a slight constriction is said to be okay. I think if you just add a layer of splits laid flat around the top of your feed, after building up the surrounding material so they can be well bedded, you will get a nearly exact 16" height which will work fine. This would give a nice flat hard surround to your feed. If you are custom cutting all of your firewood and want to make it all about 14" long, that would work too.
 
thomas rubino
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Now I literally go several years before popping my lid. But I have a tried and true fireclay perlite riser that performs flawlessly (even though I would like to upgrade to  ceramic fiber). I also have a huge transition area with an ash pit  that gets cleaned each spring . When my system was new (5+ years ago) I checked the riser monthly, so a removable lid was essential. Your going to want to inspect yours often in the beginning as well.
In regards to your question ,I understand very lazy (I think of it as smart)  I would locate a free lidless barrel and use the lid and clamp you have in your photo.  That style removable lid ,you will want some wood stove door gasket to replace the plastic seal that usually comes on them. Lifting off the barrel is just more work than I would want to do. admittedly your riser is brick so its less Likely to have issues than a home cast one... but still .  
 
Eric Hammond
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Glenn Herbert wrote:You mentioned dimensions being a bit smaller than they should be by the book... I have found that there are the standard commercial firebricks exactly 4 1/2 x 9 x 2 1/2, and a skimpier version about 1/4" smaller in each dimension. At least you don't have a mix of the two - that would be a real hassle to work with (don't ask me how I know).

It's not ideal for the burn tunnel to be only 6 1/2" tall instead of 7", but that is the one place in the system where a slight constriction is said to be okay. I think if you just add a layer of splits laid flat around the top of your feed, after building up the surrounding material so they can be well bedded, you will get a nearly exact 16" height which will work fine. This would give a nice flat hard surround to your feed. If you are custom cutting all of your firewood and want to make it all about 14" long, that would work too.



Your right Glenn, my receipt from ACME lists the brick as 8 3/4 x 4 1/4 x 2 1/2 for full or 1 1/4 for split.....but measuring with a ruler......even THAT is a generous number.  They measure smaller. Its so weird that they would make different sizes.  I'm glad you think the height of the burn tunnel will be ok, it was bothering me in the back of my mind, but there really was nothing I could do about it with the materials I had.  I've proceeded on and will find out what happens.

I had thought about your suggestion for splits surrounding the wood feed, if two of us thought it, it must be a good idea.
 
Eric Hammond
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thomas rubino wrote:Now I literally go several years before popping my lid. But I have a tried and true fireclay perlite riser that performs flawlessly (even though I would like to upgrade to  ceramic fiber). I also have a huge transition area with an ash pit  that gets cleaned each spring . When my system was new (5+ years ago) I checked the riser monthly, so a removable lid was essential. Your going to want to inspect yours often in the beginning as well.
In regards to your question ,I understand very lazy (I think of it as smart)  I would locate a free lidless barrel and use the lid and clamp you have in your photo.  That style removable lid ,you will want some wood stove door gasket to replace the plastic seal that usually comes on them. Lifting off the barrel is just more work than I would want to do. admittedly your riser is brick so its less Likely to have issues than a home cast one... but still .  



I'll go ahead and do that. It might put me a day or two behind.  No local places around here seems to be open on Sundays or Mondays
 
Eric Hammond
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Well I found a place open today(Monday)  and I did a little horse trading.  They had a barrel with a lid but no clamp, and traded me straight across for one of my barrels.  With the clamps I found it should have been perfect



Should have been is the key phrase.  I went to stack the new barrel on the my old barrel and they didn't fit......super close but just not quite.  I have a tiny pair of pliers that have a 10-1 ratio of force, very strong clamping power. I went around the barrel and crimped the edge tighter.  For reference Knipex makes the best pliers in the world.





Here's the difference, left side not crimped, right side crimped



After crimping the barrels fit perfectly!



I repeated the clay test




 
Eric Hammond
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I needed to cut the bottom out of my green barrel.  There was already a good mold line in the barrel for a reference.  I decided, cut to this line would still give me plenty of space to glue wood stove gasket.  I don't know why this picture doesn't look green, but I swear its the green barrel.



I decided the best attack would be to cut out the bottom with an oxy acetylene torch a touch big, and then grind it down to that line.



It's really hard to take a picture while cutting with a torch......



Boom, hole in barrel



Too hot to work with.....



I used an angle grinder to get clean up the edge and to grind down to the mold line in the barrel



This made for some really sharp edges, so I cleaned them up with a die grinder and a 35 grit sanding disc.



Finished barrel with bottom cut out and lid clamped on

 
Eric Hammond
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Thomas, I'm SO glad I took your advice.  Just lifting the barrel into place for mockup was a heavy terrible experience.  I do not want to do that very often!

Per the book I need 2 inches of clearance between the top of the burn chamber and barrel lid.   You can use whatever you have to create this space.  What I had on hand is way way overkill.....These are machinist 1-2-3 blocks.  They are precision ground to be 1 inch 2 inch or 3 inches depending on which way you lay them.  I placed them on the 2 inch side.



I then placed the barrel on top....it's not super heavy but a very awkward lift to clear the heat riser.



I then measured the bottom of the barrel to the brick pad the bottom barrel will rest on.  This gives me a preliminary measurement so I can calculate how tall my bottom barrel needs to be.



It ended up at 15 3/4 inches.

Since my top barrel and bottom barrel fit together, I needed to calculate my loss of height and add that to my bottom barrel to maintain the correct height.  I measured each barrel and then measured them together.





Then did some math stuff....



My calculations do not include the thickness of the stove gasket between the barrels, or thickness of the mortar of the barrel to the fire brick pad, but I assume the 2 inch measurement is not like life and death critical and erring on the side of slightly too large is better then too small......you'll also notice I just rounded up 1/16"
 
Eric Hammond
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I measured out my 16.5 inches all the way around the barrel



Then I played connect the dots



Cutoff disc back on the angle grinder to cut the barrel



Barrels in two pieces



Again, clean up the sharp edges





Barrels fit together



As a lot of you know, I live off grid, so my air source is this:  A 300 gallon propane tank aired up by a 5 hp Honda motor and a belt driven air compressor.  Kind of redneck, but works really good and is surprisingly efficient.  Takes about 45 minutes to fill up to 150 psi from empty.   I split a tractor apart to put a clutch in it and I'm still working on the same tank, almost down to 100 psi.

 
Eric Hammond
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I made a little more progress today. I measured out all the dimensions of the bricks for cutting my bottom barrel.



I ground a reference edge in my barrel to hook my tape measure to



Then measured and layed everything out.



Remember the old saying measure twice, cut once?  It's because somehow the first time you measure is WAY WAY off.  Thank goodness I took this prescription.



Cutout barrel



Installed onto bricks for test fit.....perfect






 
Eric Hammond
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For my transition/manifold, I decided to stray from the book.  There is a thread in this forum about this subject.  The one that makes the most sense to me, is the one presented by Ralf Siepmann.  You get to eliminate the first "T" and from everything I read on the donkey boards, the transition really should be massive, its a major problem for new builder not being large enough. Ralf was kind enough to send me his program for calculating the pipe angles, however this poor Missouri boy had a tough time with it.  This is the show me state, so unless I see it in front of me, it's doesn't work well.  I went with the only way I knew how.  I practiced twice on my extra scrap of barrel to make sure this was going to work. I figured the biggest transition would be with the pipe half in and half out of the barrel, so I went ahead and cut an 8 inch groove 14 inches long and then marked each end with the pipe to see how it would all fit at first.  I chose 14 inches simply because that was the length of my ruler





As you can see if fits in the barrel like so...



The cut just isn't close enough to weld together



Using a super lame, but effective method, I marked the barrel where it was closest to my 8 inch tube.  This ended up being 10.5 inches. I then cut some paper to match the contour of the pipe and made a template out of cardboard.








I went ahead and laid everything out on my manifold barrel using my new template and new length at 10.5 inches



And then cut to fit



Plenty close for welding



I'll get it all welded up tomorrow!










 
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