Sounds to me like you have incomplete combustion. Could be not enough air.. Could be not enough turbulence for complete fuel/air mixing.. (I doubt this, the Aprovecho style feed provides plenty of turbulence) Could be wet wood.. (though it would make more tars and creosote rather than carbon/soot)
In the aprovecho cook stove design the shelf is pretty important, make sure you have it installed properly. Try adjusting the pot height, it's easy to choke the flow from above. You want it as close as possible without slowing the flame even a little bit.
After all is said and done... Yes, cooking with wood can be a bit sooty/smoky either way. Shouldn't be OVERLY so, but you will likely have to put up with a certain amount. It's worth it though.
I've been toying with buyilding a new stove to further experiment with and you've given me some good suggestions. It's good to know that I can at least reduce the carbon buildup.
Yes, wet wood could be the issue, as well as the pot too close to the top. Perhaps also the stove isn't getting hot enough given the elbow design. I plan to replace the elbow with a "T" to allow more coals to build up and improve air flow.
I also plan to experiment with some of the "turbulators" presented in the heating section.
I built my stove with my 11 yr old son to boil down maple sap into syrup - a good father/son project with a tasty reward at the end. We've been impressed, but think there's room for improvement.
Welcome to the boards. IF you want to build a stove for long boiling projects, I recommend the down draft feeder box. Actually.. I've pretty well switched to the down feeder method for all my projects. Rocket stoves are quite fiddly.. The down feeder helps with that a bit, as gravity does the job of pushing the wood in as it burns. It eliminates the shelf entirely, and goes a long way on it's own toward a good fuel/air mix.
You know, besides encouraging laminar flow, the elbow itself shouldn't really be the problem in your stove. I've got a cooking rocket in my house made from six inch pipe. It's got an elbow and was originally set up in the Aprovecho style. I have switched to feeding it through the top which is generally NOT recommended, though in my case it works quite well. Anyhow, the elbow seems fine.
Try building your next stove from six inch pipe. Also a taller heat riser will add remarkable pep. Add in the down feed box, insulate to the gills and SHAZAM!! check it out..
Hi there, when it comes to cooking with wood I highly doubt you will ever get a flame that comes into direct contact with your cooking pots that does not blacken your pots no matter how clean burning the stove is!!!! The good news is this, blackened pots heat their contents quicker than unblackened pots! And not just by a small amount either. Pre-blackened pots (fire seasoned) will boil water considerably quicker!
So even though your stove may not be perfectly clean burning, it's not entirely a bad thing! However, keep striving for the cleanest burn!!!
That's probably a good point.. I build my cookers taller than the Aprovecho style.. Their design was originally intended for cultures that cook on the ground, so they are built short. Actually, it was key to rocket stove (cooker) success in being accepted all over the world, where others were not. Not only are they efficient, they are culturally appropriate in most of the right places.
Anyhow, in my culture folks cook standing up, so taller heat risers.. The taller heat riser pipe (like 2 1/2 to 3 feet) draws better, and tends to keep the pot off the flames. I think that the taller pipe (as long as turbulence and insulation is high) burns more completely as well. I see little to no blacking on the models I've made in some time..
So the secret then is...............make your riser tube taller AFTER you blacken your pots on the shorter one first! Big Grin.
That makes perfect sense Donkey. Being a tall person I have always looked at people cooking on the ground thinking.......man that looks uncomfortable......hard on the knees etc. By making your riser taller you affectively allow more time for the burn to complete before it hits your pots. What happens though when the stove has not yet come up to temperature? Same affect or does it still push a little suit?
Did you just use a cheap metal pipe for the combustion chamber as well as the heat riser and insulate them both well? (perilite or wood ash perhaps)? Or did you use insulating fire brick with added insulation?
Ive done steel, brick, cob, woodchip/clay, etc,etc... All will varying levels of insulation.. Often, I'll go to this friend of mine's place for BBQ.. I'll grab a few bricks out of his pile, build a stove and cook something.. Though every time I go back, I gotta re-build it.. He takes em apart or backs into em with his car...
Now.. I know it's a nit-pick an' all.. But, wouldn't the clay soak up and or deflect heat from the pot, reducing it's conduction efficiency??
(propeller head alert)
Seems to me that blacking on the pots is a sign of unburnt fuel. Sure, there will be carbon unburnt in the mix that will deposit on pots. It should never be greasy, creosote black. You want a dry, powdery carbon if any.
Dry, powdery carbon is indeed what I get, so at least it is not the greasy, creosote black stuff. So that's something, I guess.
And I did take Donkey's suggestion about the down feed method, changed the elbow to a "T", and have added an adapter box to the front end of the stove. Looking forward to firing it up since it is soon to be maple sugarin' time and that is the reason the stove was built in the first place. I'll know within the next week or two how the new setup works.
martinm: any one here with info \ experience with heat (from a mass heater) distribution with ducts throughout two storey house ?
Sept 8, 2018 22:58:52 GMT -8
padica: Good morning, this is a wonderful subject, please someone can help me with the theme of double and triple combustion, how it is achieved, theory and design, thank you
Sept 15, 2018 7:13:40 GMT -8
wiscojames: I'm afraid you won't get a response to such a vague question - I suggest reading through some of the threads related to your questions before asking for an explanation. People will be very generous with their knowledge if your question is more specific.
Sept 18, 2018 4:48:00 GMT -8
daniel: in my experience as I am working now on something of that nature, I have thought of making a heat exchanger and distributing the heat through vents using a slower fan. Now after a few years I realize that mass heaters give out primarily radiant heat, for
Nov 30, 2018 12:48:38 GMT -8
coastalrocketeer: Anyone posting in this shout box... if you have something you want people to see and respond to, create a thread in the appropriate forum section... this is not the place...
Dec 16, 2018 18:10:49 GMT -8
vesuvius: High Temperature Glass options,
Jan 4, 2019 16:28:17 GMT -8
vesuvius: Do any of you have experience with using the glass from home oven doors on a rocket stove? I'd like to have a viewing port on my stove but don't want to fork out for new ceramic glass. Any thought as to whether it would take the heat of a rocket stove?
Jan 4, 2019 16:30:40 GMT -8
yaya: you dont need the blowair for that temp..
Jan 13, 2019 16:43:57 GMT -8
flybywire: Glass window from an old washing machine is designed to take high temps. Cheap solution to your need.
Jan 27, 2019 0:10:58 GMT -8
coastalrocketeer: Anyone posting in this shout box... if you have something you want people to see and respond to, create a thread in the appropriate forum section... this is not the place to have a discussion... it is for short announcements
Feb 7, 2019 0:11:23 GMT -8
coastalrocketeer: you won’t likely get replies to questions here, and it is not a spot that makes holding an ongoing discussion possible...
Feb 7, 2019 0:12:22 GMT -8
TexasGonzo: Sooooo glad I found this site! Its always rewarding to find such a super group of folks! To any and all, feel free to PM me anytime. Thanks for having me!
Mar 11, 2019 18:56:41 GMT -8
jlmtech: GADGET: CONSIDER USING A JET PUMP INSTEAD OF A BLOWER FAN TO INDUCE DRAFT; NO CLOGGING.
Mar 26, 2019 8:19:28 GMT -8
michaelegan: i am unable to open the sketchup files on my mac. I used sketchup a few years back but apparently the company now requires a subscription. does anyone have any advice/instructions on how to use the program or how to view pictures without spending money?
Aug 20, 2019 18:41:48 GMT -8
mannytheseacow: michaelegan: download AutoCAD student version for free... import .SKP
Aug 23, 2019 13:33:44 GMT -8
topbaza: hi everyone, been searching all over net and this is were i need to be i think!!
Sept 28, 2019 6:16:25 GMT -8
anounaki: Hi, why I cant upload photos when I make new tread to this forum?
Feb 28, 2020 2:09:40 GMT -8
ahansen: photos under 1 mb not possible?
Jun 4, 2020 0:09:21 GMT -8