I recently stumbled across your great little forum and thought I'd share my stoves with you. The design is not classic rocket stove but includes elements of it. It's a horizontal front load, batch fed, mass stove with cook top. Now on it's 5th winter and going strong. ;D
With bypass flap open it can even be used as a classic open fire
The initial construction: I changed the top after the first trial - rising it another 3 inches and moved the bypass flap to the right hand side.
Two years ago I built another one for a friend who is a carpenter, and in return he made me a set of reusable wooden moulds to cast the refractory core in pieces that slot together. It was going to be tiled but hasn't happened so far. The door and ashbox (bottom right hand side end) has yet to be made - for a door he's still using the metal plate held up by a brick that I used for the first few years.
Top View (without metal top on): Firebox throat / riser on right, bypass flap opening to chimney in centre (flap not installed), contraflow down channel on left drops down below firebox level and travels around anti-clockwise under four bell chambers before exiting up the chimney (centre).
Thanks, that's a nice change from the usual blank expressions I get from most visitors when I try to explain how it works
The dimensions are: Outside size inc metal: Length 40-1/2" X Width 22-1/2" Height 33-1/2" Firebox: Width 12" X Height 12" X Depth 15-1/2"
I dont have a flue thermometer so I'm not sure of the flue temps, though I can touch it for about a second without burning my hand even at the hottest part of the burn cycle, and it's single skin stainless pipe. The purple tempering colours you can see on it are from when the bypass flap is open for lighting and the flames sometimes go up it.
I played with various designs on paper over several years before I settled on this. I wanted something efficient, that I could cook on, use as an open fire if I wanted, build in my cabin without major under floor work and not look out of place.
The metal acts as its second skin, allowing it to expand and contract while helping hold it all together. I initially wanted to use copper sheet on the sides and back but couldn't afford it at the time - shame, as I still think polished copper would really look great on it.
The materials list I kept when I built it came out as:
*************************************************** 101 Standard Firebricks 35 Old Red Bricks 1 Sack Castable Refractory Cement 3 Sacks Fireclay Steel: Plate steel: for top 1015mm x 545mm (5mm) for sides 2 @ 21 1/4" x 33" (3mm) for back 39 1/2" x 33" (3mm) Angle iron (40mm x 5mm): for top 2 @ 40 1/2" & 2 @ 22" for vertical sides 4 @ 32" Plus Door, Ash pan, damper flap etc. *****************************************************
The door glass is an 8" Pyrex oven casserole dish lid.
Here's a couple of better daylight pics from today.
Post by matthewwalker on Jan 31, 2013 16:58:30 GMT -8
Right on Vortex! So, if I may ask, does that materials list indicate you used a blend of castable refractory and fireclay for your casting? Would you mind sharing your mix recipe for the cast core? How has it been holding up?
Hi Matthew, In my stove I used one sack of Castable refractory cement to make the grate, throat and lintel, all the rest of my firebox is made of standard firebricks. I only used the fireclay for the mortar. In 5 years I've replaced 2 firebricks, all the cast parts are as good as new. I did make a 2" thick piece a few years ago to put in the back of my firebox to shorten it a bit, which I made by pounding up all the offcuts into grit, and mixed with firecaly and portland cement, that is still going strong. In the one I built for my friend we cast the whole firebox and it took 6 25KG sacks of castable, which was expensive, it's done 2 winters now without any cracking or spalling.
Great job! Similar to the cabin stove at Aprovecho Research Center, but yours is more ergonomic - the Aprovecho one has the flue at the front to the right of the hot plate so it kind of gets in the way.
Far better at the back like yours - leaves a clean working area.
My daughter disagrees with me on this as she is left-handed :-)
Thanks Mort, I agree, I think mine has a better use of the inside space as well. I wonder if the anvil on top is an essential part? :-) The cooktop on mine is made of 5mm steel, and it bows up quite dramatically during the hottest part of the burn cycle but other than 'saucepans at a slight angle' it's never been a problem. On my friends I suggested an 8mm top, as I'd heard that was the best thickness but he insisted on 10mm, for the first 6 months it worked perfect - no bowing at all - then suddenly the front right hand corner jumped up 2 inches and could not be persuaded to go back down. I ended up having to cut out a big square above the firebox and weld a slightly larger piece of 5mm over the top to create the kind of removable cooktop you get on most ranges, which I now see are obviously there to allow for the expansion and contraction.
The cooktop on mine is made of 5mm steel, and it bows up quite dramatically during the hottest part of the burn cycle
Some of the cast iron hot plates have ribs in underside of the casting. Not sure if these are for heat transfer or strengthening purposes. www.pyromasse.ca/articles/bellcks_e.html - see photo of second from bottom on this page.
I wonder if welding some lengths of right angle bar along the direction of flow would help stop the warping?
Last Edit: Feb 2, 2013 10:06:30 GMT -8 by morticcio
Great article, I always wondered what the layout was inside those cookstoves, looks like my design wasn't far off. I saw a broken range hotplate in a bin at the recycling centre a few months ago, it had fins about 3 inches long on the bottom and I wondered if they were there to conduct heat or to resist warping or both. We considered welding some large pieces of angle iron on the bottom of the hotplate to strengthen it but so far it's stayed straight since I cut the square out so we've let it be, but I'll definitely do it on the next one I build.
Great stuff vortex, what brand and specification of refractory did you use. I use a lot of satanite, sairset, and Icf from anh, or harbison walker as I have a warehouse within 60 miles of me. Thinking of using the dense coated with colloidal silica, minusil, and silicon carbide.
FIRED TO 160O°C: Dry Bulk Density (kg/m³) - 2200 Cold Crushing Strength (MN/M²) - 52 Permanent Linear Change (%) - 0.8 Quantity Required to Install (Tonnes/M³) - 2.23 Mixing Water - 3.5-5 litres per 25 kg bag
Type And Application: High temperature castable using Secar for use up to 1600°C. A low iron content castable with good slag and thermal shock resistance. Typical applications: Reheat furnace walls and roofs, burner blocks, furnace doors, kiln car tops and general maintenance use.
It's done 5 years in my stove without a single crack so I'm well pleased with it's performance, just wish it wasn't so dam expensive!
vimes1984: I've heard about a calculator, does anybody have a link?
Oct 21, 2016 11:00:12 GMT -8
scott55y: Are there instructions for building a casting mold for an 8 inch batch box posted somewhere?
Oct 25, 2016 10:00:18 GMT -8
yellowdog: Yellow , just trying to learn how to post here
Nov 30, 2016 3:44:24 GMT -8
robert1171: In a batch rocket heater does the riser still need to be 2 inches to the bells top?
Dec 20, 2016 9:19:52 GMT -8
robert1171: I am building a batch rocket mass stove. is it ok to make the heat riser out of pro firebrick and in a square design as to a compared circular castable riser ?
Jan 15, 2017 12:29:15 GMT -8
keithturtle: This guy did successfully https://www.youtube.com/watch?v=ZKOm3Qqxns4
Jan 15, 2017 19:29:26 GMT -8
pluton5: witam wszystkich,,,od czasu mojego pierwszego wpisu minęło juz kilka lat i tradycyjne palenisko RS ( rocket stove) zmieniało sie już wiele razy.Zmieniony wygląd i sposób zasilania palnika. Od pewnego czasu zmianił sie też kształt samej komory załadowczej
Jan 24, 2017 10:40:44 GMT -8
tommy: I have a j style rocket stove I am having a hard time getting it to draught right and make the right noise
Jan 24, 2017 15:37:52 GMT -8
esatto: looking for experience with mortar/clay slip experience... 2 bell 7' system ...old solid red clay brick bottom 2/3 of first bell and hard fire brick on top 1/3 of primary bell(above riser) looking for anyones experience with what works?
Jan 26, 2017 19:04:29 GMT -8
jura: @ Pluton5 I do speak polish, but I think the rule of the thumb on this forum is using English.
Jan 27, 2017 4:36:22 GMT -8
jura: @ Pluton5 I believe we are in deep need to use unified RS builder parlance in PL Lng therefore I'd propose to use "dopalacz"(heat riser) and "palenisko"(batchbox) (instead of "palnik" and "komora załadowcza")
Jan 27, 2017 4:41:28 GMT -8
barbalha: I want to build rocket stoves in Spain, where I live. I'll be in Phila. Till Feb. 21. I'm hoping someone here needs my volunteer help so I can learn more
Jan 28, 2017 15:18:03 GMT -8
mickykrovo: I have decided, (after few weeks) to become a "full member" of this great society. I have found it very helpfull so far.
Jan 30, 2017 10:39:37 GMT -8
panos: In order to put the p channel ,you have to make a hole ot the top plate of the firebox ,right?
Feb 6, 2017 7:46:40 GMT -8
cfrith: Panos; Yes directly inline with port with appropriate depth into port and correct width according to peters batchbox dimension chart
Feb 12, 2017 14:38:51 GMT -8
panos: Thank you very much! Have a nice day.
Feb 14, 2017 15:47:23 GMT -8
panos: Can i costruct the bell with this type of brick ? https://www.google.gr/search?q=brick&biw=1242&bih=602&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiEl6uF96nSAhWIFJoKHTiRAI8Q_AUIBigB#tbm=isch&q=%CF%84%CE%BF%CF%8D%CE%B2%CE%BB%CE%BF&*
Feb 24, 2017 15:55:01 GMT -8
panos: i guess these would be good for making columns inside the bell since they have this additional surface area.
Feb 24, 2017 17:59:35 GMT -8