I built smokeless wood stove for the camp. Used two different sized BMP (Bain Marie Pots) and it works great! for inner can ID 16.5, OD 18.7, H 19.0 (cm) for outer can ID 18.0, OD 20.1, H 21.0 (cm)
I think You will find that it burns better and consumes less fuel if you reduce the amount of primary air. You can test this easily by covering over a bunch of those holes in the bottom with a disc of sheetmetal. I have found over the years that these require very little primary air for the best most efficient burn. Too much primary air causes too much up-flow thru the stove, towering flames and higher fuel consumption… Nice build!
@@iamtheboxer in the inner bucket where you put the wood. Primary air feeds the wood/coals directly. Secondary air is heated between the chambers and feeds/ignites the wood gas(Released by the primary fire/heat) above the wood. Too much primary air creates too much up flow thru the burn chamber. This reduces the time the gas has to break down and burn in the heated secondary air so you get smoke condensing/becoming visible 2-3’ above the fire. I have found that the area of the primary vents needs to be ~1% of the area of the bottom of the inner chamber/bucket… area of a circle is pi x radius squared. A 10” bucket has 78 sq/in of area(5”x5”x3.1416). 1% of that is .78sq/in. A 1/2” hole has about .2 sq/in of area, so about four 1/2” holes or more of a smaller size. You can always add more, but as demonstrated in many of these, holes are a pain, so it is better just to not have to drill them in the first place. Of course there are some other variables, but ~1% is where I have had my best burn.
@@rronmar thanks, this is exactly the kind of information I was looking for. I'm preparing to build my own and after watching tons of these videos I suspected that most people were allowing too much airflow. Do you have any data on the ideal for the secondary air holes and the holes in the outer chamber?
@@pasfromage secondary hole formula? No not really, as I don’t drill them. I have the outer chamber overlap the top edge of the inner chamber and leave a small gap between the two for the secondary air to pass. Done this way, there are several ways to assemble that will allow you to adjust this gap to tune/experiment with the secondary airflow. On the ones I build out of water heaters i have run gaps between 1/8”-3/8”. You could also cut notches or “V”s around the top edge of the inner chamber with a cutoff wheel on a grinder far easier than you can drill holes. I only drill holes when I need precision fastening, as they are a lot of work. I cringe sometimes watching these builds with all the holes that they really didn’t need to drill. Here is a slideshow diagram of ones I build… ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-XtzoCQBoldY.html Good Luck, its cool when you get it dialed in…
Has anyone combined tornado effect with this design? Instead of fully cutting the holes, use the material as vanes to create a vortex, Rocket stove style. Also is the heat from the secondary burn lost to the air?
@@MikePogmore I havn’t seen anyone try a vortex on this style. Not sure how effective it would be for a few reasons. There isn’t a lot of it. If there were more secondary flow, it wouldn’t have time to get superheated, so would be less effective at cleanly burning off all the woodgas to burn smoke free… you really want the hot secondary air/o2 to flow out over the fire to mix with the gas and ignite. The low pressure column of secondary air can only travel so far horizontally, so angling it to create a circular flow would increase the horizontal distance it is trying to cover. This would probably create a center column of unburnt gas that the secondary air simply cannot reach. The gas in this center area would probably not ignite, and would condense back into smoke above the fire. In answer to your question, yes the secondary fire heat is lost to the atmosphere unless you cook something over it:) Thats the heat you feel around one of these pits, as you don’t really feel much heat around the can, as that outer surface is internally air-cooled by the secondary flow between the inner and outer wall. Thats the drawback of these pits, your feet will get cold:) i recessed mine into the ground in my fire pit area so the people setting around the fire can enjoy more of the heat…
I know I'm a little late to the party here, but my daughter and I are getting ready to make this same stove to take camping with us since this is all that is allowed in many national forests. I absolutely loved the idea of the L-brackets to make the pot stand
Great video, I made mine out of a restaurant food warmer (double lined) it is just a bit smaller than yours and works great. I will add the legs and pot holder as you have, gracias for a well documented video.
I've asked many youtubers about doing this exact thing with their designs, and they all said no need. Well done. Using the science around how it works to maximum effect.
Great video man! Now add a same diameter bowl on top, flip it upsidedown and cut the bottom of it, you have a flame concentrator on it (it really does help). You can fix it in place with those metal paper clips but your pot holders should work fine as well
Would it be helpful to have a third ring of holes in the middle or 2/3 of the way up the pot? Or what difference would it make if the second ring of holes were a little bit lower?
Several years ago I made a similar one out of a Jasmine tea tin and a Progesso soup can. It's small and fits in a side pocket of my ruck, and it works great using mere twigs for fuel. Also, a beer can chicken holder fits perfectly inside the soup can, and it holds my camp cookware. Since that first one, I've made probably a few dozen as gifts to friends
I really appreciate what you share thank you so much your a great person you know the gas is so expensive due to Russia and ucrain war the stove is useful right now. It's smokeless our neighbors will not be disturbed..we can't use firewood because of the smoke. Thank you so much God bless you.
a sheet metal hood over one of these. hood vented to outside. make heat, cook, nice idea or invention. pot size and metal type can be adjusted to particular requirements. it is the great design that is the amazing part. thank you
Would also increase the draw. Could become a rocket stove and improve efficiency at the same time! Couple it with a primary air throttle and you can show it down once it's going and just burn the wood gas.
Add a mantle level for increased heating and secondary gas combustion. Those holes on the bottom look like they will clog with ash fast. Add some more holes in diameter around the inner vessel 3 cm above the bottom.
Thanks very much for this great video. This is now on the to do list. :) With the 6mm holes around the rim of the inner pot, I wonder if you got a 6mm rod, inserted in to each hole one by one and pushed the rod 45° in the same direction, whether the flames from the secondary burn would spiral? Cheers!
Awesome build! Very nice materials used and quite enjoyed the whole mood. I’ve made something similar on my channel using an old rusty small beer keg (single walled) and found many similarities between our videos. Take care!
think of same design..but using two steel drums ex: 45 gallon steel barrel. I wonder how long of burn time you would get out of that size? heat output ? cooking surface area? the air flow engineering is great, the size of the barrel would depend on what you want to heat with it.
that's right. So, instead of adding excessive firewood, add the appropriate amount. When the charcoal fills up, you can poke the center of the charcoal with a stick to improve airflow, speed up combustion, and reduce bulk.
Hi, it looks really cool and I tried this too. I managed to light it with pellets, but the flame was very weak and didn't go as high as yours. What is your advice?
Does anyone know the pot sizes or model numbers? These videos are great but also include the material sizes in the description would make them perfect.
Please explain a bit more, I realise that increased air helps burn better, especially when insulated with an air sleeve provided by the double layer, but your flame is still yellow, indicative of incomplete combustion , so there is likely some smoke.
Are the size of the pots too big for your requirements? A pot of water, etc. doesn’t need that big a fire to boil or heat up. I’m thinking about what size Bain Marie pots to buy. Your example looks a little big for cooking. What do you think?
Agree 100%. Diameter is too large. Also a smaller diameter with this height should work better I suspect. An additional section above about half the height would increase the chimney effect. Check out Heath Putnam's channel, he has a great playlist on wood gassifier hobo stoves.
I have made a couple of these and found the one with the smaller holes around the inner pot rim burned better that one with larger holes. I am guessing that the smaller holes kept the gases from passing through to quickly and increased the heat and gas content of the smoke? This is hypothetical, as I said I only made a couple of stoves.
