Murray Green

Joe; I didn't bother to look into legislation as I have no insurance and don't really care what the nanny state has to say about what I do. I will say that Glenn Herbert was correct with his assessment of the base
configuration of my stove. It was in late December and very cold. The stove was fired up at 6 am and was running full bore all day. (Too much draft, heating Saskatchewan) At 2 am the following morning, I was still on
the computer and could smell wood smoke. I rushed over to the stove and to my horror, saw smoke curling up through the base bricks. Panic set in and I removed the wood in the stove with some tongs and began to let it cool down.
Thankfully, no fire but definate floor damage. I will rebuild with airflow under the stove as noted by Glenn.
  My stove is too effecient with 20' of verticle chimney and my heat loss through the air intake is severe. I will require a preheated outside air source or exhaust damper to slow down the draw. At 25 below, it will
not heat the house by burning all day. My wood stove will heat the house in a couple of hours. I love the fast lighting and clean burn of the rocket stove. We used our regular wood stove last winter and although it heats the house well, it is dirty and uses a lot of fuel. I haven't had time to rebuild yet but when I do, I plan on going to a batch system.

Take care all,
Murray

Steve; I don't have enough experience to comment on your temps as mine has only been running for a few weeks and I don't have the cobbing finished. Your top
temp is the same as mine (575 - 600). The lower part of the outside barrel is 375 - 400. Where my flue starts vertical is 230F. I get no smoke and a very easy start as
I have a short 11' of horizontal pipe and 20' of chimney. Mine is an 8" system.

Take care,
Murray Green
Saskatchewan Canada

Glenn; Thanks for the note. Yes, I was aware of the flat top on the heat riser and it was one of those "I should have" moments but decided it will work fine as is.
I also gave a fair bit if thought to the material under the combustion chamber. You may be correct in your observation but my assessment was that 6" of dissimilar
material would be sufficient to dissipate the heat under the combustion chamber.
There is lino and shiplap under the ply and no floor insulation as there is a basement.

Take care,
Murray

Bob; Thanks for the note. As my house is a story and a half, I have to go around 20'. My rocket chimney is now the highest point as it is above the peak of the house.

I meant to throw in a few dimensions with my stove. The fire bricks are 2 1/2" x 4 1/2" x 9". The fuel feed tube is 12" high on the inside. My horizontal throat is 10 1/2"
on the inside and 25 1/2" outside. The heat riser is 42" (If I remember right, would have to take the top off to measure). The flow area of the stove is 50.75 sq. "
and my 8" duct has a 50.24 sq." area.
The stove fires up instantly with absolutely no smoke and begins to roar (rocket) right away. Wonderful.

Take care,
Murray

Here is a few more.

Thanks for the replies. Here is a little background on our stove. I wanted a large unit as we have a very old story and a half house. The spot we chose for the stove, only
allowed for a 6' bench. I decided on an 8" unit. We put 3/4" ply on the floor and covered with tin foil, then a layer of common brick. Then a leveling layer of cob, followed by
a layer of fire brick in the stove area. We have a J tube design, all out of fire brick. I rolled some 10 ga. steel for our heat riser exterior and used perlite between the brick
heat riser and the steel. (18" dia.)and capped it with some perlite cob. I then rolled some 10 ga. for the outer barrel (I didn't want to use a gas barrel) it is 24" diameter.
I built the manifold out of brick and used 8" diameter ducting, down and back in the bench and put in a water trap as the ducting goes vertical. Our bench is not finished yet
but the ducting will be totally encased in cob.
We have so much fall work to do that we won't get to finishing the stove until later but it works so well that I had to write in. I'm not sure how accurate my cheap electronic temp gauge is but it is showing about 600 degrees F on top the stove, about 400F at the bottom of the outer barrel and 200 F on the ducting as it goes vertical. I wish I had more room for more bench length as it appears to me, I am wasting some heat.
I've attached a few pictures.

Thanks,
Murray

Hi Folks; I just wanted to thank everyone on the site. I have been lurking and studying rocket stoves for some time and finally built an 8" mass heater.
It works perfect right out of the chute. No smoke, excellent draw and an aggressive sound. I've had it running for several weeks now and I like it more
each day.
We have a very old drafty house and have been heating with a home made wood stove for about 10 years. As we are getting on in age, the volume of
wood cutting was getting to much. Here in west central Saskatchewan Canada, we have some pretty aggressive winter and we usually go through about
14 cords a year.
It the first of Oct./14 now and it gets below freezing at night but warms to about 40 - 50F during the day. So far, one firing a day is plenty of heat.

Anyway, thanks to all of you for the info that I have gleaned that has allowed me to build such a great unit.

Murray Green
Saskatchewan Canada