Wood Gas Stove Science| Paint Can Wood Gas Stove Optimization! Making a good stove GREAT! Part 2

[@happykillmore349]

I thought I might be the only person nerdy enough to want to optimize a diy wood-gas stove, and now I found exactly what I needed. Brilliant stuff in here.

[@heathputnam9524]

I did need out for a while… hope it helps a little! Thanks for commenting and watching!

[@heathputnam9524]

You may want to subscribe in case I start back up! 😂

[@briannorwood9983]

Your work in this area is nothing short of amazing

[@heathputnam9524]

Thank you! Thanks for watching!

[@THEGLASSMANSWORLD]

Thanks for sharing and for doing all that math so we don't have to now! This is awesome science!!

[@heathputnam9524]

Happy to help! Thanks for the comment!

[@hardluck7769]

Excellent Video of Explaining How this Science Works !! 💯👍 Thank You

[@heathputnam9524]

Thanks for watching

[@morayjames92]

Thanks for posting Heath, very much enjoying this series.

[@heathputnam9524]

Thanks for watching!

[@morayjames92]

@@heathputnam9524 I have found that you can increase thermal conductivity between your burn pot and the outer can/vent. Steel is not very conductive thermally but thin aluminum which is very conductive can melt.So I married the two materials using a steel can for the lower 1/4 to 1/3 of the total burner chamber and slid an aluminum can over top of this to make up the upper portion of the burn pot. Obviously this require finding cans which fit and I found I could stretch the aluminum can enough to obtain a very snug fit.This is not an easy solution nor is it very practical but I mention it in case you or others want to experiment with it there is a substantial improvement in heat transfer. I hope this is of interest and of some value to this discussion.

[@heathputnam9524]

Interesting idea! I’ve been thinking of a three can design to help with the hear transfer, but this is a great idea! Thanks!

[@morayjames92]

@@heathputnam9524 it does work very well help with some extra heat to the air channel so pressure is increased a little bit more than when using two steel cans. The only draw back is finding cans to fit in the size you want but it does work well.

[@bluehydrogen1]

Thanks for the knowledge

[@heathputnam9524]

No problem!

[@OhmanRizboalter-ib5yg]

Nice one! second video i saw on this channel and got me hooked! excited to see if i can find experiments on larger steel barrels which is what i‘m looking for. Cheers!

[@heathputnam9524]

Good luck finding experiments! How big are you trying to go with?

[@OhmanRizboalter-ib5yg]

​@@heathputnam9524 Thanks! I want to go for a 55 gallon barrel as an outer container and a 150 liter former domestic hot water tank (made of thick steel) as an inner fuel container. So round about maybe 70-90 kilowatthours of fuel per run.

[@heathputnam9524]

@OhmanRizboalter-ib5yg what is the primary purpose?

[@OhmanRizboalter-ib5yg]

primary purpose is charcoal production from waste Biomass. secondary purpose would then be cooking huge amounts of food with the mates

[@heathputnam9524]

@OhmanRizboalter-ib5yg you will use less primary holes. My design is built to convert over to burning charcoal after the fuel is totally reduced to charcoal. That requires more primary air unless you want to dowse the charcoal once blue flame begins. Hope this helps!

[@OWK000]

Your reburn is the most impressive I have seen. Why can't they make the commercial ones burn this well? Math works!

[@heathputnam9524]

All the commercial ones are built for lowest cost not best design. Thanks for your kind comments!

[@aparecidomiranda6637]

Ótimo vídeo Parabéns 👍🇧🇷🇧🇷

[@heathputnam9524]

Obrigado pelo comentário!

[@blakelaing2417]

Very helpful, thanks!

[@heathputnam9524]

Thanks for watching!

[@b0b0-]

Nice work

[@heathputnam9524]

Thanks for watching!

[@aidennymes6335]

as i'm watching this I remembered an idea I had back in the days, to put a spiraling path inside the double wall so the air needs to travel around the burning chamber a couple of times before it comes out of the secondary holes. that way it has more time to heat up instead of traveling straight up. realizing this would probably involve heat resistant JB weld and a lot of fiddle work cutting and placing all the spiraling strips i had in mind. but maybe there is another way to force the air to be longer in the heating zone (inside the double wall). keep up your videos !

[@heathputnam9524]

I have tried this and failed, but I didn’t invest a lot of time in the idea. I think the longer path slows the flow and more air goes through the primary holes and changes the way it burns. Maybe I should revisit the idea though! Thanks for the comment!

[@aidennymes6335]

@@heathputnam9524 would love to see some experiments about this. I don't think it would slow down the airflow in a significant amount since there is no aditional resistance created for the air, but just a longer path to the exit holes.

[@jacobopstad5483]

You could maybe just try a spiraling strip of something (think Slinky!) like a spring or something like that.

[@heathputnam9524]

Thanks for the comment!

[@Julioargent]

I'm beginning to see your videos, I like them a lot. Could you add a cardboard at the exterior can (or another isolant material), so you could touch it and also have a greater heating of the air? Thanks a lot for all your teaching videos about nice can stoves! !

[@justinw1765]

You could use wool (especially good if soaked in a half and half borax and boric acid in water solution), ceramic fiber coated with high temp silicone (600*F or higher *), carbon felt, or the like, as long as you don't cover the holes. Cardboard might technically be ok, but when these stoves are really burning, that outer can does get pretty hot and could potentially catch the cardboard on fire or at least start to char it. A way to test this, is to spray paint the outer can with some high temp paint, and when it is really been burning very hot for awhile, use a IR laser thermometer to check the temps (if you don't paint it first, it won't read it accurately btw). If the outer can is getting to 400 to 600*F range, then using cardboard wouldn't be the best idea (especially since a stray spark or the like could catch it besides the outer can temp issue). (Incidentally, even untreated wool can handle that temp range no issue, as it doesn't start to combust until around 900*F, and it is self extinguishing in nature anyways). Insulation should/could help it to burn hotter and more efficiently, but the keep in mind that the hotter you get it, the faster the metals will oxidize/rust. You could also coat the inside of the outer can with one of those special high temp, low thermal conductivity, highly IR reflecting coatings that contain zirconia. This would probably work even better than wrapping the outer can in a high temp resistance insulation for a few reasons. Adds less weight, less fiddle factor (no chance of blocking the air intake holes etc), and once temps reach 500*F and higher in the fire, more and more of the heat loss/transfer starts to occur via IR and less via conduction and convection. Think of it this way, your heat source/fire, as it gets hotter and hotter, its emanating/radiating that light like IR energy more and more, almost like its becoming like light more and more (the ultimate example of same would be Stars). That, and air that those temps, as it gets hotter, it becomes more and more conductive, thus less and less insulating. If you're going to do the above, make sure that you use a high temp paint on the outside of the inner can, so that the reflected IR can go through and back towards the fire more efficiently. Shiny metal surfaces do reflect some IR as it is, though steel and SS much less than polished aluminum. * Btw, the silicone coating on the ceramic fiber insulation is not for heat resistance or insulation, but to stabilize the fibers. The fibers of this material are brittle, and as they break away, they become a potential inhalant toxin and can cause some real damage to human lungs. The high temp silicone coating helps to keep them in place and thus prevent that. Cheers

[@robertjolliffe2612]

Great stuff thanks

[@heathputnam9524]

Thanks for the comment!

[@stevenrobertson4470]

You've got me excited to try out the 5:1 ratio of primary to secondary air. As far as the spacing between the cans, would it be optimal if the cross sectional area (area of inside of outer can minus outside area of inner can) would equal the total area of secondary holes? Or would it be optimal if the cross sectional area between cans were to equal the area of secondary and primary holes added together?

[@heathputnam9524]

Honestly I haven’t dug that far into my data, but there is definitely an optimum space. Too much and the air doesn’t heat as fast as it needs to get flow too little and the laminar air flow is interrupted. Sorry I don’t have a better answer on this but in my experience I would say 1/4 - 3/8 inch difference is best for can stoves. A larger stove will be able to handle a wider gap. Thanks for watching!

[@DiggingBuddy]

I wanna build this, so cool, thanks for doing this research and making this so simple for is

[@heathputnam9524]

Let me know how it goes! Thanks for watching!

[@jimijam1972]

Love it! Can not wait for the next one. Just out of curiosity, could you place a "char" tin down in the middle of the zone? You would have a second, smaller source of gas that would vent from the tin, towards the direction of the perimeter jets. Might be a temporary boost of heat, while creating char cloth at the same time, to be used for the next stove light up.

[@heathputnam9524]

You definitely could do that! Thanks for watching!

[@joancandalino8742]

How far up from the bottom did you drill your 9/16" holes on outer can? Would the primary air allowed by the outer can need to be equal or greater than the primary air into the bottom of the inner can? Or equal to or greater than primary plus secondary air because it's feeding them both? Or am I missing something? 9/16" / 2 = .281, .281 * .281 = .0789, .0789 * 3.14 = .248, .248 * 7 = 1.74 sq in. area of air input through outer can?

[@heathputnam9524]

Trying to catch me! Haha! You can absolutely choke the stove if you go too small on the fresh air intake, but it does not need to be equal or more. It’s a great point though. I usually start smaller and open them up as needed. Maybe I should talk about that on a future episode! Thanks for commenting!

[@mattmatty4670]

Cool thanks mate

[@heathputnam9524]

Thanks for watching!

[@chriskelly4619]

Loved it. I need the science behind this so i can apply it to other ideals. How about bigger application for tent or tiny house heating ,cooking or water heating. I see lots of videos but none that give me the science behind it. Thanks.

[@heathputnam9524]

I think maybe “Downdraft Debunked” may help. I may put together a more scientific video soon. Thanks for watching! I have a wood gas playlist on my channel... it may help!

[@rainierjosephcastro450]

Hello sir... Is it possible to produce pure blue flame like the one I saw in you tube? Thank you n more power...

[@Asiergr]

hi there, could you explain me a little bit more how you calculate the maths of secundary hole size? I would like to make a bigger wood gas stove and this part is important. thanks. Is it possible to explain in cm? thanks I am spanish and is difficult to me sometimes understanding inch system.

[@johnanders7538]

Look up area of hole chart

[@heathputnam9524]

Watch the series and look at the subtitles! They are all in Spanish! Thanks for watching!

[@noah786]

I’ve been thinking about how to convert a tent stove into a wood gas stove. Maybe something that could burn at a lower temperature for a longer time more efficiently. Thanks

[@heathputnam9524]

Thanks for watching!

[@1Bonehed]

I’ve been thinking about these & wondering if an exhaust wrap or some other form of insulation may help retain more internal heat to cause a more efficient secondary burn. Love the vid &’wished I’d seen it earlier

[@harrymills2770]

People might learn what they need and go on to their own experiments. But I can see your channel having staying power and continue generating revenue for years. You can always do other stuff and garner fresh views and also generate a trickle of views, long-term. Just keep making them and don't be afraid to tackle other tech.

[@cristian77tm]

super video ,when another new video ???

[@heathputnam9524]

Soon, thanks for the comment!

[@toml.8210]

What dpo the angled secondary hole do; some kind of vortex generator?

[@heathputnam9524]

Yes, thanks for watching

[@fr.marklichtenstein8892]

Is there a place where the parameters are collected an published? Do you have a sense of how this will scale? I'd like to make an outdoor firepit w/o smoke in two sizes at least 5 gallon bucket/can size and stationary fire ring in the yard.

[@heathputnam9524]

I have not documented my result on a website. The design will scale but the ratios change as the volume between the inner and outer can changes. The hardest thing about making a larger stove is the flame must close off the pyrolysis zone or you will not get efficient burn. Thanks for the questions!

[@chriskelly4619]

Can you teach us about the pyralysist zone , air flow, wood gas generation concepts please. Something drawn out to show the gas flows and air flows. And relationships. Thanks

[@heathputnam9524]

I do have a video called TLUD explained... it may help. Let me know if you need more info! Thanks for watching!

[@melissahoffman4687]

Awesome video! :) Keep them coming! Share your uploaded videos on lots of websites like facebook, instagram, and twitter to get more viewers. :)

[@heathputnam9524]

Thanks for the ideas!

[@bettebette9881]

Why do you need the holes on the bottom of the inside can? Won’t the ashes fall through and interfere with the air flow?

[@melissahoffman4687]

Try trimming the bottom of the inner can so you don't have to worry about the holes on the outer paint can lining up with the soup can. :) That may allow the secondary burn to stay in contact longer.

[@heathputnam9524]

That sounds interesting, can you elaborate?

[@melissahoffman4687]

@@heathputnam9524 I guess you can say that.

[@melissahoffman4687]

@@heathputnam9524 I'm glad the ideas help. Share the ideas away.

[@melissahoffman4687]

I am obsessed with trying to keep stoves safe. Trying to think outside the box. Like what you do too.

[@robertjolliffe2612]

I’m interested in a heater for inside a room for additional heat given power bills increase now 2022. Thanks Australia

[@heathputnam9524]

Always be careful with an open flame indoors and CO gas. This will not smoke and will put off plenty of heat into a room. Thanks for watching!

[@mnight207]

I long for the day when you say "umm" again

[@heathputnam9524]

Not sure what to make of that! Thanks for watching!

[@slickwillie3376]

I'd like to see somebody make a gasifying rocket stove. Rather odd to consider, since the gasifier gets fed from the top, and the rocket stove gets fed from the bottom, but there might be a way. For example, perhaps an upside down rocket stove with a double wall design, and a ramp to feed it from the top. Some air would flow down through the ramp, down through the wood chips and through the grate supporting the wood chips, into the bottom chamber. Around the outside of the bottom chamber would be an air inlet. Also the bottom chamber would have some accessories; such as a tray that slides out to remove ashes and a damper to control air flow. The air from the damper inlet would mix with the gasified burn products and travel up through the outer channel to the top, through "jets".

[@GeneWalker-u9z]

Hi, from N.C.

[@alexdesousa6578]

If you're in the Northern hemisphere, your rotation should be anticlockwise, due to the coriolis effect on low pressure systems, and vice versa in the southern.

[@heathputnam9524]

I actually have a video that shows there is little to no difference on the airflow or quality of burn. At least nothing I could measure! Thanks for the comment!

[@ramavijaya148]

Sir, If we pump air, thro a computer fan type will it work better. (not for camping type ) but in home it can work excellent.. pl try .

[@heathputnam9524]

The type of stove I want to create is naturally aspirated, not forced air. That being said I have experimented with forced air, it burns fast and hot! I have a couple videos, but honestly it felt like cheating. Thanks for the comment!

[@ramavijaya148]

@@heathputnam9524 true . Sir it is for 3 world countries , in villages , where gas cylinder is costly , not affordable , available . Not for camping etc sir . U have already done most of the work , finishing them will be a great service for them

[@heathputnam9524]

What would be the primary fuel? That makes a big difference in the design.

[@ramavijaya148]

@@heathputnam9524 same wood broken pieces only sir

[@therical77]

Thx

[@heathputnam9524]

Thanks again for watching!

[@mohdafzaluddin4589]

V. Good

[@heathputnam9524]

Thanks for watching!

[@daniellorca4452]

Hi Thank you very much. I would find very useful if you could give measures in metric as well. I build guitars, and to place the frets exactly, i find easier to use millimeters. Thank youand sorry for the bother.

[@heathputnam9524]

The build video does give you metric and imperial measurements! Thanks for the comment!

[@kaytme5915]

How about Chimney pipe stove? I have extra 8 inch & 6 inch black steel chimney pipe long enough to have the outside pipe much longer allowing cooking better.

[@kaytme5915]

Double walled======

[@heathputnam9524]

It may work, I haven’t tried it. Just use the same principles and good luck! Let me know if it works! Thanks for watching!

[@jacobopstad5483]

Have you thought about adding a stove pipe?

[@heathputnam9524]

The pot stand works like a chimney. Thanks for the comment.

[@sharkofjustice1787]

Красава, то что нужно

[@tycjanksiazek]

Even simple math in imperial units is a real nightmare :)

[@heathputnam9524]

Sorry! I try to include metric but sometimes forget! Thanks for watching!

[@katipunero113]

Please make one of these that does not make the charcoal turn to ash

[@dalecarpenter8828]

right hand vortex left hand vortex in southern hemisphere

[@heathputnam9524]

No… depends on the way you bend the holes… done the experiment! Thanks for watching!

[@tamtrinh174]

it's funny how a lot of youtuber see losing views is a kind of problem LOL

[@justtinkering6713]

I found one of these made from stainless steel on Amazon for only $17. Much better.

[@heathputnam9524]

Yes, you could always buy a Chinese trinket from Amazon but what will you learn from that? Thanks for watching!

[@justtinkering6713]

@@heathputnam9524 Thing is, it won't rust out. I learned a lot from you and others. And Decided it was cheaper and better to buy one already made.

[@heathputnam9524]

Understood! I was really hoping to create a following of people to share ideas in an open source type of scenario. Like a wood gas can stove community… thanks for the comments!

[@beakfordclakington1337]

hi man. just hypothesising here, with no real schooling in thiss... but, if the air between the containers get hot enough, then does it matter that the 2 walls are not as 'close as you'd want them'? and 2: maybe feminazis left your channel when you found out you applied maths, and got "hurt" and upset by it i hate '''smart''' phones tho. subbed God speed mate

[@heathputnam9524]

I have found that if the cans have too large of a gap the flow is not as strong out of the secondary inlets. That being said maybe insulation around the outer can would help with heating the air between the cans. Either way, if you are trying to build an efficient can stove with as few parts as possible. Try to stay with a close clearance between the inner and outer can; 1/4 - 3/8 inches or 6 - 10 mms. Thanks for the comment!

[@radagast6682]

Very good tutorial with one exception. You made the math too complicated. The ratio is the same whether you use a round hole or a square hole. Area of a 3/16" square hole is .03515625, and the area of a 1/4" hole is .0625. Do the math, and it comes out the same. Sixteen, 3/16" holes and forty-five 1/4" holes.

[@heathputnam9524]

OK, but how are you cutting a 3/16 square hole? I do not think the calculation for the area of a circle is too complicated, but I could be wrong… thanks for the tip and thanks for watching!

[@radagast6682]

@@heathputnam9524 You're not cutting a square hole, you are using the math to determine the number of round holes. As I stated above, forty-five 1/4" holes has five times the area of sixteen 3/16" holes, whether round or square. I like that you keep improving your design.

[@heathputnam9524]

Either way… doesn’t really matter. I just like exact calculations… thanks for watching.

[@LADYMONA]

Math alert!

[@heathputnam9524]

Yeah, sorry! Thanks for watching!

[@LADYMONA]

@@heathputnam9524 I love it, thank you. :)

[@harrymills2770]

Progresso soup can is fatter. Perfect fit in 1-qt paint can.

[@dalecarpenter8828]

don't use the pellets ! use sticks and don't stuff it full !

[@heathputnam9524]

Why not stuff it full? I use pellets for a constant, in experimenting you need a constant. I also bring pellets when I go hiking, they are lightweight and I live in the desert,now, where wood is less available.

[@PAINACAB]

shiiiiit. i thought i over think things. this is ott.

[@heathputnam9524]

Haha! Thanks for watching!

[@sigmarider786]

did u tell that math to yourself!!

[@heathputnam9524]

Yes

[@pabf2745]

This can burn worse than the part 1 cans

[@heathputnam9524]

Watch the whole series! It is a process to optimize one of these stoves. I try to lead you through the journey one week at a time! Thanks for watching!

[@harrymills2770]

It's "pyrolysis," not "paralysis."

[@larrywise8109]

Boo math. I'm tuning out. This just got too complicated.

[@heathputnam9524]

Really? That’s too bad! Haha! Thanks for watching!