Sawdust Woodstove Revisited 

I think you should use the saw dust stove you just built. You have all the saw dust you need. It appears loading it in the morning will keep your shop warm all day. That allows you options for the woodworking heater. You would have choices in which heater to go with, ones you already have or build with the fire brick. Maybe use one while you are saving to complete the fire brick. But as they say, " it's your stuff, you decide". Nice video. I had never seen a sawdust stove before. I think they're pretty cool. R

I've been using a 30 gallon drum sawdust burner like this to boil maple sap for 10 years now. Small operation - I get about 3 gallons of finished syrup per year. Instead of lighting the sawdust from the bottom, I light it about 1/3 of the way down from the top, by suspending a burning rag in the sawdust hole with a piece of 1/4" steel rod. Remove it once you get a good flame going. This avoids the issue in your first video of the lower layers of sawdust burning first and then the upper layers collapsing and plugging the air hole. Also less smoke. Much of the smoke is from the oxygen being consumed in the lower part of the barrel, none left for the upper layers of sawdust, so it just smolders there.

My father-in-law (born 1907) worked in sawmills throughout Oregon. Sawdust was always a waste product. He (plus co-workers) used a sawdust burning stove that worked about the best for them. Similar to yours in some ways. 55 gallon drum with lid and a 35 gallon drum with no lid plus stove pipe plus 3/4" water pipe. Run the stove pipe from the bottom edge of the 55. Set the 35 inside the 55. 3/4" hole in the lid of the 55. Fill the 35 with sawdust. Start fire on top of sawdust. Put lid on 55. Insert 3/4" pipe in 55 lid and drop to just above sawdust. My father-in-law said they had to manually adjust the 3/4" pipe periodically (there must be a better way) and the air through the 3/4" pipe acted as a bellows to keep the sawdust stirred just enough to create a continuous burn for the shop. I was really never given more details.

One issue no one commented on is the benefit of a good DRAFT ... Your first attempt (video) didn't have a very tall chimney (Stack) to draw/pull fresh air through the compacted sawdust and allowed the fuel to smolder instead of blasting the heat up the center etc. And maybe ??? the forming tube was on the small side . I appreciate you doing your videos without editing out the booboos. Something many people do not comprehend is the direction you install the chimney pipe. It makes a serious difference The crimped end needs to point down to minimize the draft getting stifled from outside air getting introduced into the chimney draft... And your chimney needs to run 250-300 F or hotter to maintain a good burn in a wood furnace or stove I am sure the same concepts apply to this stove as well But the taller the chimney the more the draft the hotter your burn and shorter the burn time and always be aware of Monoxides Just some observations to ponder on . A SINCERE THANKS for your efforts

Great idea and build. If you add another section to the burn barrel to reduce the internal gap between the top of the inner burn barrel and the lid of the outer barrel to about 2 inchs of clearance. This will produce a better draw of the fire and produce about three times the heat. Also it will fix the smoke problem :) good luck and God bless.

Perfect project to create heat from all of sawdust. I'm going to use my everlast equipment to make one of these.

Two things. One, love the music choice. Two, if you use a cardboard tube as a core, it'll simplify building and ignition.

Unless you have a use for the sawdust, I'd say rocket mass in the woodshop to maintain a more consistent temperature there and use a combo of the other two for the metal shop. (Provides a way to get rid of the excess sawdust other than compost - not recommended)

Another thing to remember is the humidity in the atmosphere will condensate after the burn and create issues. some of this is created by your crimped ends pointnig up.

Recycle material , knowing how to weld and make stuff great fun . keep it up , good positive skills to learn and encourage others to use . Dispose of sawdust too .

Finally! I've built 2 sawdust stove heaters and neither would work with the top on. Can you provide dimensions? I'd like to duplicate what you did. Thanks for posting!

rocket heaters are neat indeed. My suggestion would be to use the stove that you can use with your readily available (and virtually free) fuel: Sawdust. if you can make the rocket or mass heater digest it, then good. But it might require modifications like builduig a hopper and feeding device.

I built a double barrel wood stove to heat a non insulated 50'x40' (2000sqft) steel built shop, 1st run to burn the paint off, it was 18 degrees out with the man door and 8' car door open it heated the whole shop toasty. Since then I never needed to run it that hot, Very good stove application, and easy to build. Recommend to use stainless barrels with removable tops for easier build and cleanouts. Yes a little more money, but then you have a long lasting and incredible heat ranges. Also since then I did add insulated inside walls. Good luck. Dave

Excelente, muchas gracias.

Do you have room for more than one heater in the shops or can they have wheels installed so you could switch between them... if one solves a waste problem but has other hardships like packing it etc. then alternate them... back up is always a great idea never rely on just one....it might get real cold sub freezing a few days.....

well rocket stove and mass thermal if you can do it, then make a small press to press saw dust blocks so u can burn them also , i suppose its convenience versus availability versus money

Use the wood shavings and dust to bed the chickens and then compost the bedding or in the winter top dress the garden and let it convert like a sheet mulch planting through it instead of tilling.

My sawdust stove, I made the top of the burn chamber 1" or less between the top burner. This way the top gets over 550 deg. Fahrenheit. I use an old washing machine drum under the stove so it will never clog up the center hole. Your almost there with the design.

Ok, first great video. With that said, this my take of which would be better of choices. Now as for convenience, the sawdust stove would be better than mass rocket stove in that with rocket stove, unless u modify it it with larger drop box you will have to fill it up every couple hours, put it together and cost is slightly more to finish building. It would also take up more shop floor. Advantages: takes less wood logs, burns hotter and can time it better for amount of time in shop. Where wood dust stove, u will not have to do anything with it for 6-8 hours, burns cleaner. Disadvantages: cant really control burn time so when u leave will have to leave it unattended which could be problematic depending on your situation, uses more wood dust then what rocket stove would probably burn in same time (again dependant on which is more convenient to obtain and cost friendly).

Trés bien fait et trés bonne continuation merci

This is really good, it works on the same principle as a Swedish log candle.

If the rocket mass heater keeps the shop somewhat warm overnight, wouldn't it be easier to bring it back up to temp the next morning? If so, I think that would be the way to go. But, is this going to solve the saw dust issue. It seems a waste not to use the waste. Wow, now I'm confused again. Good luck.

Choosing the sawdust burner or rocket stove would surely depend on what raw material you have to burn. Also you can leave the sawdust burner and get on with work, while needing to work out how to feed the rocket stove.

Thanks for the awesome video Cy! I'm thinking about building one of these for my small shop. Could you tell me what the purpose of the outer barrel is? Is it just for added safety or is there something else it does that helps the heater work the way it does? Thanks, Tim

I have not the place to test it. could you please make an experiment with sawdust in a flower pot with a hole on the bottom and use a jet torch to light it up from the bottom? But this time only trough the hole.

If you mortar the brick with the 'proper' heat resistant mortar and place a metal barrel over the brick and then covered it all with cob (as it's supposed to work), the "rocket mass heater" would be your best bet. But if not, the best heater would be the rocket stove/heater you built last year.

I was wondering if you could use the saw dust stove in reverse on your mass heater burn from the top ex oust out the bottom fireing from the top of your sawdust stove?

Thinking the hole should be wider and use it then use your firebrick and your metal fabricating abilities and make a pizza oven!!

All you needed on the other one was a better air intake. And, might as well pull the intake air from outside.. It's got to come from somewhere anyway.. Might as well be cold air, not warm shop air. Control the burn intensity from the intake, not exhaust.. Works better anyway. Now, i am watching the video.. Yep, intake is sufficient. You can get it to burn hotter by increasing the hole in the rec tubing and pipe you use to pack the sawdust around. 3" hole with a 4" intake to supply the air at a faster rate (Think Rocket). Min Exhaust then would be 4". Also remember, you can make a crappy stove work with a tall smokestack. Always use at least 4-6 foot. If the final install is going to be taller, it only gets better after the install.. Concept: As heat rises in a pipe, it looses temperature. As it does, it shrinks in volume, so, requires more volume to go up the pipe. This is why you always want a larger exhaust.. This is also where the rocket effect comes from. Add 6' to a short stovepipe and listen to the difference.. Also, the taller the burn chamber (sawdust), the greater the draft. One other thing you could do is make the inside taller or cut the outer barrel off, but, cut from the bottom. The Exhaust is borderline height now. Should be a touch higher. Cutting the barrel off by 3" should help... No sense in having more airspace between the inside and outside barrel. The closer the top of the outside barrel to the top of the Inside barrel, the hotter the top of the barrel will get. And, when you get all of the Ratios correct,, you will definitely see the difference between dry and damp sawdust. In a typical Rocket stove, dry/wet wood is the biggest factor you deal with . Brand new 2x4's from inside a lumber store will burn Great. Leave it outside under a tin roof after 3 days of rain, you will see a noticeable difference. The more thin wood you stack into a rocket, the more surface area is exposed to flame, and the less air flow volume, creates the Rocket effect. Fast Air moving over the burning wood creates the big heat.. Thick Blacksmith using coal, when he cranks the blower handle.. The stove you have now will work. Very Dry sawdust with it. Increasing air flow next greatest improvement.... Remember. Always a larger exhaust than intake... And, always more air available to intake than the port intake "In" the stove and every stove you build will work, and teaks I mentioned above will make it better. I started building test rocket stoves with center blocks, adding exhausts, then small tube metal and increased the sizes until I got to my 6" Rockets.. The final "Ultimate" Rocket stove was my "Long Horn Rocket Stove".. When I built it,,, no more tweaks were needed.

I love it thank sir

I built a 2ft x 4ft rocket mass heater with a 55g drum and 6in flue pipe buried under sand and cobb out 10 ft across the floor of my greenhouse and back to the barrel so it would help to heat the verticle stack out and 8ft high to draft well. It fires and burns nice and hot but don't work worth a darn cause the fire box (made with fire brick) is way too small. Load it up with wood and it's burned up in 15/20 min. I don't use it and now I got a 500lb monster just in my way. It's a great concept and I like it's smokeless fire but I can't stay up all night feeding it. I suggest build one that will fill up with 3 to 4 ft logs or lots of rem boards so it will burn for 4 to 6 hrs and heat up your mass to stay hot for 12 to 16 hrs.. just a suggestion from a disappointed rocket stove owner. Thanks

If you miix some old vegtable oil with the saw dust (just slightly damp)you will get a much hotter burn

I feel like the exhaust port in the outer barrel, in reference to the height of the ash barrel, is to high. Maybe lowering the exhaust port would would eliminate the smoke?

Hi, good job, but I'm from a tropical climate of 2 degrees Celsius in winter to 33/35 in summer...I know it's a stove, but from there on ...no idea ...greetings from Argentina...

Could you add waste oil to your saw dust and gain a bunch of BTU's?

Use "doubledup" claypot its cheaper and easier to make.doubleup meaning smaller pot inside bigger pot to make it sturdier and protect your self from too much heat from stove.

θεος τελεια !

Just for kicks, how 'bout a small conveyer that delivers sawdust from a hopper, directly into a rocket stove? It would be an electric motor and a speed control.

in your last try you used too coarse a material and didn't pack it good enough, which led to the collapse of the whole, your design was fine. I think ya just wanted to show off this time Eh? Naw us tinker guys just always do it better the second time around.

Need a small outside air intake in outer barrel.

Is it for sale

the rich are probably laughing at this attempt and hard work to keep warm and use waste materials,well done mate

Самоделка на коленке. Но разжигать можно было забросив горящую бумажку сверху.

I think a big part of why you were having smoke issues is that the stove was running too rich, too much fuel, not enough air, your inlet should flow the same as the exhaust, you have it choked down to 2-⅜ if that was a 2" former pipe, and what a 6" exhaust? 4.43 square inches inlet, 28.27 square inches exhaust. And no damper.

COVERING WILL NOT WORK....