dave marth

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since Apr 30, 2012
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Recent posts by dave marth

Yea. I've thought about adding mass to my stove but that doesn't clean up the smoke. I just can't see how a heat riser out the back of my wood stove wouldn't clean up the smoke some and still keep the stove safe and not overheated. Maybe pictures would help you guys visualise.

Ps. Not trying to be rude here.

Thanks again

Dave
3 years ago
I understand what your saying. My stove wouldn't be operating any differently as far as i can see. I would just have the air inlets open all the way instead of damping them down a little once it's burning. The heat riser I pictured being made of vermiculite board so that should be fine. The only concern would be the exhaust thimble exiting the stove but my stove is made of 1/4 inch plate steel. After the heat riser it's pretty much the same as any other system.
3 years ago
Hello all. I am on to my next rocket stove project. I have a brilliant idea for my situation I think and I would like some input. I originally had an all nighter big Moe wood stove made in the 70s. It's in great condition. It just smoked too much for my liking so I built a rocket mass heater and burned that for a season. I spent my entire winter splitting wood and feeding my fire. It was too much to keep feeding it so I came up with an idea to use my old stove as my firebox / burn chamber.
My stove has the flue exit horizontal out of the top back of the stove. I was thinking I can ad a 90 degree bend up from there and connect a heat riser. Then install a barrel over the riser like normal. Now I was thinking I could load my stove up get a hot fire going in the stove and maybe with a p-channel going into the heat riser like a batch type rocket, this may clean up my smoke.

Is this too easy and obvious to be true?

Thanks
Dave

Ps. I'll try to upload some images of my wood stove later today.
3 years ago
Yes. I left out the cob bench and instead put firebrick inside the barrel as mass. Not as effective as I would have liked. And for the bell I just called it a bell because that's what I though that was called.

Anyway I'm redesigning everything completely. I'm gonna make a new thread called wood stove converted to rocket stove. I'll ask all my new questions there.

Thanks everyone here for all your tips and help. Great community.

Dave

3 years ago
I tried the batch box one time and I made it to fit about 30" splits. It kept smoking out of the riser giving me the impression that it was too deep of a burn chamber to run.
3 years ago
Yes the fire is visible through gaps in my feed area. I left these unsealed like that because then I am able to remove the couple of bricks and clean out the tunnel. I realize that if it was sealed the draft would pull the fire down better. And cutting my wood shorter would fix my fire climbing up problem but then I would also be increasing my load frequency. Thanks for your tips though. I appreciate it.

Maybe my solution is to make my riser a lot taller so that I can make my feed chamber about 30" deep. Then I still want to try to fit a cover on the top of the feed to let air in but no flames or smoke out of the top. I am visioning something like a square cap with a funnel shaped Cone going down onto the fire so that the air is blowing down through that focused hole and no smoke or fire can come up.

Anyone follow or is that too confusing?
3 years ago
Well that's not what I wanted to hear, but I believe you. The reason I was staying away from a real batch box is because this summer when I was testing, I tried to make a batch box that was long enough to fit the entire length of my 30 inch wood inside. I could never get it to burn clean enough and assumed it was because my burn chamber was too deep. I never did investigate any further. I remember when I asked you about the depth of the box burn chamber you said that the length wasn't a big issue. Is that still accurate.

Thanks guys.
3 years ago
I understand what your saying about the fireball potential. I have to think there must be a way to maybe close off the primary air inlet and maybe open a port on top of the feed tube bell to clear gasses out before opening and reloading.

But anyhow, if there was a bell on top of the feed tube and an air inlet a a lower point than the bell would this mess with the mechanics of how th e system burns? I can't see how it would as long as I stick with the proper air ratios.

Here is a video showing what I'm talking about with my sheet metal feed tube top.
Rocket mass heater feed tube bell cover:


https://youtu.be/jx0sQmpGdD4
3 years ago
So the heating season is coming to an end and I actually stopped running the heater for the most part. I have learned a ton with this first build. Recently I have filled my house with smoke twice and that was enough for me to quit for now on this current stove. I think it smoked back because temps were a little warm outside, not real warm but just enough to cause draft problems. I didn't incorporate a cleanout in my stove pipe so for me to prime the stove pipe I have to take the barrel lid off and light a paper in the bottom of the barrel where the pipe exits. Its a huge pain in the butt so that's gonna need to be incorporated in the next build.

Second thing i learned is everyone who said basement is a bad idea for a rocket mass heater is absolutely CORRECT! I just needed to find out for myself. For the past winter I have been running up and down my basement stairs about 15 times a night to reload and shuffle shake down the burning wood. I expected a couple trips up and down the stairs but not that many.

Next is my upstairs was around 70-74 degrees every night, after burning for about 5-6 hours. This is the real reason that basement location is a bad idea. The entire basement needs to heat up before the heat travels upstairs. I had a wood stove before I build this stove and the heat came upstairs way faster, that's because the rocket mass heater needs to build its heat first then it can spread around the house. So needless to say, i tried to spend all my time in the basement for easy refilling and staying warm!

Next problem was my feed tube. I mortared the entire heater together with just fire clay alone. This stuff is very fragile. A few weeks into running the heater, I noticed sand was falling through cracks in the feed tube area between the firebricks meaning my clay mortar is cracking and failing. I have the entire jtube surrounded by perlite and then on top of the perlite is sand. That's the sand that's filling into my burn tunnel. This is my first time mortaring with fire clay and I didn't know it would be that fragile. Now I know.

Another problem I had to combat is the fire climbing out of the feed port. This could be caused by a couple things. I used thicker splits than I believe I should have been using, causing them to not crumble down to coal as fast as I would have liked. This left more time for the fire to climb up the sticks. Also, I think if my feed tube was a little smaller the faster air flow might have kept flames down a little better. My fix was to bend a piece of sheet metal into a square and basically raise my feed port about 10'' higher to be taller than my sticks I was burning. Then I placed another piece of sheet metal over the top of the square to allow about 25% of the surface area of air flow in. That way if the sticks did flame up then the fire was still surrounded by more feed tube.

And the blue tarp and tiles under the stove are no problem at all. Under the burn tunnel, I laid a piece of ceramic fiber blanket on top of some plain bricks and build on top of that. It seems like a VERY effective insulation keeping everything cool enough to not transfer heat where I didn't want it.

So now whats next? Build a new one upstairs in my living room. There currently is no stove pipe in my living room so I will have to install that this summer. I want to do a build similar to the dragon heater castle builds out of the clay flue tiles. I will ad a cleanout t so that I can pre heat the stove pipe much easier. If I build one in my upstairs, my living area will be toasty within 2 hours I assume. My basement would go from 59-60 to 70s within an hour and a half with my current heater.

Now hears my innovative thought. I want to make a cross between j-tube and batch stove. That's almost what I had once I raised my feed tube with the sheet metal.

Is it possible to make a regular j tube stove then make a little bell that goes over the feed tube like a can or something the right size for the feed tube, and add a couple air ports for the secondary combustion? Here's what I think will happen. The sticks in the feed tube will obviously climb the sticks but the air port will be at a point that is proportionate to the system, not at the top of the feed tube. This way the draft wont want to run backwards because the feed tube air flow will be low enough that it still drafts correctly. This way its almost like a batch j tube. The flames would be going on in the feed port and the gasses would get sucked into the burn tunnel where more air is mixed in for a clean burn.

Does anyone have any experience doing this mod to a regular j tube?

I hope my wording is clear enough to get the ideas across.

Thanks
Dave

3 years ago
What do you mean your keen? And I'm just gonna maybe do a clay slip on the outside and that's it. Maybe stick some rocket on the outside for a little more mass. Don't know yet. Any suggestions for the outide?


Also I want to make a glass front for the feed tube. Would an oven door glass for a regular electric cooking oven be high temp enough? I was thinking of looking in trash for a scrap oven and steal the glass from it.
4 years ago