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 Thoughts on 2nd year burning Batch Rocket Stove

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Gary B.



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Join date : 2014-03-18

PostSubject: Thoughts on 2nd year burning Batch Rocket Stove   Sun Mar 06, 2016 6:42 am

Gary B. here from Minnesota. The burning season here is winding down and I thought I would share how my second season went.

First some news. I was in the middle of my second rocket stove build (with cast riser) this past fall, when out of no where my health got bad. So I had to put the project on hold. To make a very long story short after many months of specialists it was determined I was not absorbing enough nutrition (vitamins). So with this news I have been put on major supplement program including B-12 injections. Now six weeks latter I am almost back to normal. Ok enough of that, lets get to the burning season of 2015-2016.

Ok a little back history. My Large Batch Rocket Stove (The youtube video titled "Batch Rocket Stove Details" posted for me by Dale (trying2hard) is my stove I will be sharing about. Well this may jump around a little but here goes. After burning it daily all last year I pretty much had it figured out as I tested in every way I could think of(I have windows over batch box and directly over the riser plus I have high end probe thermometers in many key locations so I could really get the big picture. Bottom line I was very happy with it and I had impressed a lot of people with it. Now all was not perfect. Problem was I was always holding it back (heat out put wise) so I was opening windows or restricting the wood amount in the batch box.

Don't get me wrong it was do able and not that much of a big deal. But in the back of my mind I knew my stove was over sized for the my 2000 square ft shop. Now a little FYI. My stove in its original build had a pretty elaborate combustion air preheater. It also had a regular combustion air system like any old wood stove right on the front of the stove. So like I said I burned my stove every way and the preheated combustion air made such an improvement in heat out put and another big thing is my wood load last longer. So I had decided my new stove I was going to build would have the best combustion air preheater I could think off. So I set out to build this new stove (cast riser like PPotty's with this supper preheater.


So this was last August. I have the cast riser completed, all parts built I am literally a week of welding away from done and I got sick. So I knew I could not finish the new design but I could build a very similar combustion air preheater for my original stove so that is what I did and I have been burning it daily all winter. I wish I could post pictures but I am old and I have had no luck. So basically I built another complete burn chamber (smaller) so I could get it inside my existing stove complete with a door.

So I already had all combustion air controls for my stove so pretty much my new burn chamber bolted in (no bottom as I made it to fit over my cast iron grate and no back as it butted up against the back of the stove burn tunnel in the center. I put a sliding bolt on draft on the door of the new inside burn chamber but I have found it best to leave that sliding draft open and control all air with the original preheated air controls. I also put a window on the top of this inside burn chamber and I already had one on top of the original burn chamber so I can watch the fire. This new burn chamber is 18" deep, 10" wide, 12" high. So any combustion air going into this inside burn chamber (preheater)(the only place the wood is burnt) is taken from all around (accept the back).

So the entire burn box is the preheater. Dale does have pictures of this entire system. Now with this new combustion air preheater I can slow the air going into the burn chamber so less volume in and less volume out. Also I can burn the stove even hotter now and I can burn it lower. I have no trouble maintaining the temperature I want. The entire inside burn chamber is built of .375 mild steel. Wood consumption down. I have never once let my shop go below 60 degrees all winter and I am just over one loggers cord(48 inches x 48 inches x 96 inches)(128 cubic feet) burnt red and white oak.

Couple last thought as this is kind of rambling. My opinion is of all things you can do to your stove preheated combustion air is by far the most important for both efficiency and it also makes it so easy to control heat out put and all around operating consistency. One last thought. I have ceramic glass in my rocket stove one is directly over the riser(I have seen over 1800 degrees F) no problems plus two directly over the top of the fire box inside one has purple flames continuously on it no problems. I have noticed this glass lets heat through it way way more than steel. That being said I think this really helps my preheater heat the combustion air. Now if anyone would like pictures of my system or would be willing to post,

edited email from the site to save person from being spammed can put back at anytime

gadily
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Sun Mar 06, 2016 7:22 am

hi gary I can post them up for you if need be I have emailed you from my email account

but its not advisable to leave your email address on full view its up to you but normally id edit those details out

otherwise you can be inundated by junk mail been there had it all myself
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Gary B.



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Sun Mar 06, 2016 8:53 am

Ok thanks. I am not very good at this tech stuff. Wondering if you got pictures I sent ??
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Sun Mar 06, 2016 9:00 am

yes gary ive got them

if you need to send any pics get in touch via the pm system onsite that gives me a heads up that youve sent me some pics over or video

as can do both my side as well as t2h
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Sun Mar 06, 2016 9:16 am

gary B's stove addon spoken above on his first post above













Last edited by gadily on Sun Mar 06, 2016 9:38 am; edited 1 time in total
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Sun Mar 06, 2016 9:22 am









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drj12567



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Mon Mar 07, 2016 2:04 am

MR. Gary B. what a stove you have made. Good craftmanship . Metal fabrication very good too. I want to know how you are super heating your air. I am building a rocket stove from the free plans MR. Trying 2 Hard had on his youtube channel. I know boilers,air intake and stuff like that, I was a boiler tech on a aircraft carrier U.S.Navy 24 years service. 1200 psi steam plant. I have been a welder for the past 30 years,trying to gets the parts for my rocket stove, I have the tubes and  some other stuff. Any ideas will help. Have a good day in Minnesota, hope you are better.
                                                 Donald Joyce Advance, North Carolina
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Gary B.



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Mon Mar 07, 2016 7:01 am

Donald, I can see from my ramblings a guy could use more info so here goes. My stove in its original build had a preheated cumbustion air system. I watched PPotty's video and I could see the back of the stove and heat tunnel were red hot so I built a 2 inch wide air chamber on the entire back of the stove. Then I ran the two 2 inch stainless tubes(holes spaced entire length) out of that over the top of the original fire box. (you can see these in above pictures.

I have a slide air control under this chamber through the base of my stove. Last season I used this once my stove was up to operating temps along with an air control under my cast iron grate in the bottom of my burn chamber. So last year and this year I am actually using the exact same air controls (so air entering under the fire makes my stove easy to light and get up to operating temps fast and zero smoke.
The fire is ripping almost instantly. Once the stove is hot (15-25 minutes) I switch around my air controls to where my under fire air setting is just enough to maintain a slow rolling fire(flame). Then I adjust the preheated air slide to where my burn chamber flame goes purple with just orange
Tips on the flames.

I have windows over burn chamber and this is easy to do and it makes for a very interesting fire to watch. Now this is the way I ran my stove last year and this. Now Bare with me as I explain the differences between last years performance and this years. Ok so last year I was using the entire batch box and the one original preheater and the under grate air like I explained above. Now this did work good but this sweet spot where fire was burning perfect had my stove pounding out the heat and I ended up opening windows, putting in small wood loads, and even at times I would open my riser bypass and just let heated air out the top of my riser go strait up my chimney.

Now I know where I would have to set my air controls for this stove configuration so I can tell you the differences with this years supper preheater. I will get back to this latter. So it is obvious my stove is over sized for my 2000 square foot shop. Also at this point I have learned preheated combustion air really makes my stove special over burning it with the old style front of stove air draft control (room air temp coming in directly into front of fire box.

I have both controls and believe me I tested all burning configurations and preheated combustion air makes a world of difference. So I am designing this new cast riser rocket stove for my neighbor who has caught rocket stove fever. So I know I want the air entering my burn area(batch box) as hot as I can get it. So I decided to pull all of heated air from all around burn area (batch box) into the top and front of burn chamber.
So if you look at pictures above you can see where this air enters my combustion air preheater (6 holes top of door). Well when my health went bad I decided I could build a simple smaller burn chamber combustion air preheater and just slip it into my existing stove and kind of test my idea. I am so glad I did. Now just so we are clear any heated air coming off my batch box(burn chamber)is captured and has to enter those 6 holes into the burn chamber,heat tunnel, riser...  

There is no other way out. So I have burnt this stove all winter with this preheater and here is what I have learned. I have probe thermometers so I can tell the combustion air entering the burn box runs between 800-1200 degrees F. depending on how hard I am running it. For same heat out put I have to run air controls much more closed down. So now fire is burning slower but just as hot as it not getting cooled down by combustion air flying in and out of my burn chamber. So less air in less out.

To make sense of this look at it this way to make it easy lets say we have two  stoves with a chimney exit temperatures the same say 200 degrees F. The difference is one stove has to have a high volume of air going through it to produce its temperature. The other one like mine is set with combustion air nearly closed off (60-70 percent smaller opening).
So yes they are both exhausting 200 degrees but if you measured the cubic feet of 200 degree air just look at the heat that got away from you. Not to mention I believe the slower the air going through the burn chamber the more time there is to burn up all available energy and time for your heat exchanger to scrub off as much heat as it can.

Another thing worth mentioning is with super preheated combustion air the stove is very easy to run. You ask what do I mean. Well my stove now burns very consistent. Set controls and it will maintain heat out put temps all through entire burn cycle. Air control setting openings are consistent to out put temps (all season long) So it is easy to run.

I mentioned earlier with this preheated air I can burn hotter and cooler than before and always smokeless now. I hope I answered your questions and this helped you out.
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Mon Mar 07, 2016 7:19 am

heres garys build for you

http://woodstoves.forumotion.co.uk/t524-gary-s-stove

his first season running the stove

http://woodstoves.forumotion.co.uk/t656-end-of-burning-season-report-from-minnesota

extra info

http://woodstoves.forumotion.co.uk/t617-batch-box-wood-loading-and-few-thoughts

gary ive got to ask how long is your winter season 6 weeks or 2 months or more

id still love to see your start up video before you put the log into the system to run it at low
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Gary B.



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Tue Mar 08, 2016 4:21 am

This year I started burning my rocket stove  daily on November 1 and I am still burning it but starting this week I am only burning it for 4 hours in the morning (one loading) to knock the chill off. Yesterday in Minnesota it got up to 60 F in the afternoon.  Now I spoke yesterday about adjusting my rocket stove to burn in what I call the sweet spot. Well you kind of asked the question about getting it to and burning it in this configuration so I will try to shed some light. First off 99 % of the time I burn my stove from 7am to 7pm. So 12 hours of burning 7 days a week. (I am a retired Tool& Die Maker) so my shop is a machine and welding shop. My passion is building things with my hands and I always have a project going (accept when I got sick). I also get a lot of satisfaction teaching young people and over the years some guys have come through here that have gone on to be fantastic fabricators. I am rambling again. So back to your question.

So lets start on how I do things starting at 7am. I get out to my shop and fire is completely out and my stove is cold(room temp which is always 60-65 degrees F. Here is a brake down of my morning stove operation in order. I open the outside stove door, then I open the door on the inside burn chamber (the combustion air preheater pictures above(burn chamber sitting on my bench before install inside my original rocket stove pictures show before and installed),next I rake all ashes down through my cast iron grate into my ash pan, next I light a fire starter (pressed fiber waiffer 2"x2"x1/2"and lay it on the grate but closest to the burn chamber door, then i open air control wide open under grate, then I open the heat exchanger bypass on the top of the heat exchanger (so now heated air going up my riser can continue to go up directly out my chimney instead of being turned back down and exiting out the bottom of my heat exchanger.

Then I start placing my wood on top of my fire starter one layer about 3-4 inches thick (three smaller size splits of white oak). Then I close the inside preheater door and I close the outside door to within 1/2 inch of closed. The fire is ripping right out of the gate smoke free, in 20-25 minutes I have my stove up to temp (say riser temp of 1200 degrees F), so now I add more wood on top of a nice even bed of coals (three little bigger pieces cubic amount of 10"x10"x16" and I close both doors (the inside preheater door and the outside door, I also activate my heat exchanger by closing the by-pass at the top of the heat exchanger, I let it burn like this for 5-10 minutes, now my stove is hot my combustion air preheater is really doing its job.

The air all around my inside burn chamber(combustion air preheater) is 800-1200 degrees F. This super heated air is trapped between the inside burn chamber and the outside original burn chamber. The only way this air can get out is through the series of holes in the top of the door of the inside burn chamber, heat tunnel, riser... Now I have control of the amount of air I let in to this air chamber around this inside burn chamber.  So now I reverse the burn. What I mean is up until now this fire is getting all of it combustion air from under the fire through my cast iron grate. So what I do is I almost close this bottom air down to nothing. I watch my fire and when it goes to a lazy wavering orange flame I am done adjusting the lower air control. (this control is open very little. I mean you can barely see the little opening.

Then I finally start letting in this super preheated air. Now I can see through my windows into the burn chamber. I watch the flame and start adding this preheated air the fire starts changing from all orange color to purple. I continue to open the air control until my flames are all purple with just orange tips. Now I am in the sweet spot and this stove is burning as good as it gets. Here are a few things that I have learned. With this combustion air preheater the air entering the burn chamber is already 800-1200 degrees F, think about that for a second. If you put that temperature of air into a burn chamber you would not even have to light the wood first and it would be burning right off.

Now I may have made it sound like there is a narrow window of super preheated air adjustment. This is not the case in fact it has made this stove very easy to operate as I can easily adjust the heat out put I want and still have the burn so perfect. Another thing that is really nice is this stove has become a set and forget. I mean it holds a temperature and burn time so consistently it is hard to believe. Now I can here some guys saying wait a minute so let me clear this up. To get the wide range of heat out put and the purple burn with orange tips on the flames it takes dual air adjustments. So what I am saying is this.

In my case what I have found best is I shut off my preheated air to the burn chamber and let the fire settle to an orange flame, now depending on my heat out put need I adjust this orange flame up or down by my under grate air control. Once I have this where I want it I start adding super preheated air to the burn chamber and I watch the flame transition from all orange to all purple with just orange tips on the flames. Now I hope I explained that so you can understand what is happening in my stove and what I am doing to get this burn. So in my opinion if you are building a rocket stove for heat you need combustion air control on both under fire combustion air and for supper preheated combustion air.
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Wed Mar 09, 2016 4:36 am

Well done again Gary, cannot imagine what the heat production would be like if it were not in the belly of your other stove.
Glad to hear your health has recovered.
If you remember I did let you know I did not have the time to post photos or video this time around.
I have too many irons in the fire right now, no pun intended.
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Gary B.



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Wed Mar 09, 2016 4:54 am

Oh yes and like I said no problem. It sort of worked out better anyway as I was able to test this system all winter. My report is as accurate as it could be now that I have burnt it for this extended length of time. I do thank you as you and PPotty inspired me to take on this project which has become one of the most rewarding.
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Wed Mar 09, 2016 11:02 am

not including the interest in your build that you gotten from it gary

the surprise of heat that you have gained as well as the low use of materials that you need to burn within your wood stove

sooner or later your going to get so much interest in building these you just may end up too busy building them for others who want one of them for there propertys to match your own system and also for the less use of fuel that is needed within the builds of them

also there is your tinkering as it was too powerfull for you after its build so now you know its sizing thats needed or adjusted but thats swings and roundabouts building the right one for the size of dwelling thats needed insulation and builds have to be taken into consideration what may heat yours may not heat someone else build if its built differently
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daveden



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Wed Dec 21, 2016 8:16 am

Gary, Do you have any plans? Even a sketch with dimensions would help. I am going to be building my heater soon. I have a 2000 sqft shop with 14ft ceilings. I think your stove in the original configuration would be the ticket for me.
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Wed Dec 21, 2016 8:44 am

there is some dimensions on some of the videos of his build

you can also guess some of the scale via the pics that have been provided

an update to the stove has confirmed a much smaller box can be used to create the same amount of heat output from the built stove
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daveden



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Wed Dec 21, 2016 12:07 pm

gadily, Thanks for the reply. I have watched the videos a couple of times and have not seen any dimensions. I agree that the firebox can be made much smaller. I was just wondering how big it was originally.
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Wed Dec 21, 2016 10:57 pm

theres alot of detail via the batch rocket stove details and by a persons height when working on the build

http://woodstoves.forumotion.co.uk/t524-gary-s-stove
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FerrousBueller



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Thu Jan 19, 2017 8:13 am

Gary B., can you estimate how much additional fuel is saved by slowing the burn using the super heated air ?

TIA
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Fri Jan 20, 2017 12:18 pm

from my reading its 4 cords down too 1 1/2 cords using the rocket stove to burn with

but he would need a full season to burn with and depends on if the conditions matched the year before

being as low as 1 cord or 1 1/4 of a cord used per year is a whole saving when your buying 4 cords per year

the extra savings whilst others are there and can see this to there 4 cords or higher just by using a different stove is the saver

so id say buying in 2 cords the first year the second year 1 cord should be ample enough to run for 2-3 years running

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Gary B.



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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Sun Mar 26, 2017 3:23 am

Gary B. here from Minnesota. To anyone who might be interested in buying my Batch Rocket Stove I am selling it now for what I have in it in material costs ($2,000). I am just putting the final touches on another batch rocket stove so I do not need two. Today's date 3/25/2017  

This stove can heat a small or large shop using very small amount of wood. I will keep an eye here for messages or questions.
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gadily
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PostSubject: Re: Thoughts on 2nd year burning Batch Rocket Stove   Sun Mar 26, 2017 10:51 pm

hi gary i had wondered how you was

id say wait a little until you are satisfied with your new stove at least you can adapt it if needed

looking forward to the new updates on the new system build

a further question here how has your system held up this year

any further updates to the stove and how it performs with wood usage

best also try advertise that system within your area papers or sales area free ads

yours is a tried and tested system with some heat power behind it so it should sell rather well
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