Jon Lim

Hey big al,
Thanks, i am getting plenty of draw and I can even boil water on the barrel. I can not, however, get it so hot I can boil water quickly in a pot. That's my concern. Great draw, great everything, somewhat adequate heat. I will try and upload a video at some point.

Hey big al. I have the book, read it about a half dozen times and wrote my thesis citing it several times. My thoughts are purely theoretical and asking on others on their experiments and experiences.
Thinking purely theoretical, the gas still being in the exhaust means that not everything is being burned off. What could theoretically be causing the gas not to be burned off inside the barrel? Sealed up, same issue which leads me to believe the shirt exit flue is working against me allows get the air to be cooled too quickly.
Is my theory incorrect?

Thanks for your reply. The reason I got into rockets stoves was the relative easiness of using scrap so in used what I had available to me. I'm not one to give up easily so I will put all effort forward to making a 4" work.
Would it be beneficial to use a smaller diameter exhaust to build up a bit of pressure in the barrel? It would slow down my burn but build up heat (think like an h box on an old motorcycle). Or would it just be beneficial to increase the length of the exhaust pipe to make it difficult for an easy exit of gasses.
Now. I drilled into the side of the barrel to make it movable in case of an emergency. The 4" is also a bonus because i can hide the light from the flame pretty easily.
What I haven't done yet is seal any gaps where air can be sacked it by the holes I drilled in the barrel. Could this also be my issue? I was trying a dry run before I completed the whole thing

So, i got a 55 gallon barrel and put a rocket stove together but I think I am having some issues or did something wrong. Anyway, I took 4"pipe and surrounded it by a 6" pipe and filed the space with vermiculite. I tested the flue before installing and worked life a charm. I cut the holes in the drum and resealed it with the original lid (this, making it easy to move until I decide where to put it). I have rough install of flue and exhaust. Exhaust is also 4"and I just put a 90 degree connection there. The 6" flue outer shell is maybe 1 to 1.5 inches shorter than the stack. The stack is roughly 2 inches from the top of the barrel.
Anyway, I get a good burn and good exhaust flow but I think I have 2 issues. 1) outside the top (50 to60 degree weather) gets hot enough to barely boil water in about 15 to 20 minutes. Take the lid off of the pot and it won't boil at all. 2) the exhaust fumes will either snuff out any flame that comes near it or the gasses in the exhaust will ignite to create a longer flame for a short time. So, i know the wood is being gassified but it doesn't seem to be burning completely in the barrel.
A few notes. I can get the flame and embers inside the 4" intake hot enough to get a drop forged wrench bright red with very little wood.

So, with that said, dies this all seem normal? When I extend the exhaust will it make a difference? I will be adding a burn chute which will be a 4" round have receiver so that the wood will stand straight up. I will surround that with a 6" receiver and insulate again.

So far I'm pretty happy with the outcome but some advice on this would be greatly appreciated

Would running the piping in the insulation around the riser in an OPEN loop (open top bucket) to 1) heat the water without turning it to vapor and 2) cool and insulate the riser be a viable option?

Would Pool Krete be an acceptable option for insulation on a mass heater? It is filled with vermiculite and cement and seems to be a possible, solid option for insulating the riser. Think it's a possibility?