Matt Carkhuff

paul wheaton wrote:So I get this question:

if it's not sealed correctly couldn't you essentially poison everyone in the house?

It sounds like paul is really battling this question: "so if I'm an idiot, how will I know if I'm stupid??"

One of the most dangerous things this world has is stupid people that don't know they are stupid. I get along fine with the stupid people that are willing to admit there are stupid...just saying..


Oh and the post just above this one Kirk has a pretty sweet half bell bench setup... I wonder if Donkey has any video of that stove??

there's a few methods around this. (I am still trying to figure this out too before I build one)

1. obviously you can-build your own house in an area that has lax building codes

2. contact your insurance company and provide them a detailed design plan, including actual exhaust temps (you'll still probably have to use triple wall insulated pipe to exit the house) and see what they think.

3. the devious thing to do: make it quasi-portable (not a mass heater, just a rocket) so you can just move it easily.

4. most costly, but no company should have an issue with, especially if faced down wind and covered:outdoor rocket stove

from what I have read; covering the barrel does reduce the heat ouput (at least immediate heat) and can make the top hotter. I also have seen instants of videos where they claimed the drafting was reduced (looking for the video now) and that it was less "rockety".

my thought is that with young ones it may be a good idea; just leave some of it exposed like the top 14" or so. I am still gathering parts to build my first RMH so don't take my words as gold yet...

i think it would work. I'd probably aim the top of the bottle away from the heat, just because, but water supposedly stores 5 times the amount of heat vs. air, so it should hold the heat quite a while. I mean, most are building thermal masses out of broken concrete so filled bottles of water can't be any worse... the only issue would be that no one has really tried or proven it, so you may be the first! post your results please.

I think the efficiency comes from the fact that it burns wood about as hot as possible (i.e. fast drafted air into the wood fire). Then that heats the metal tank/barrel up which convects the heat into the room. The thermal bench is just a way to squeeze even more out of the heat produced. I mean even a potbellied barrel stove will produce a lot of heat, its just whether that heat is effectively distributed that determines the efficiency...I guess a small fan would help that some.

THe link to the project in my last post he used a square 4" chamber IIRC. I am planning on a minimum of a 6 inch system, but may do a 8inch system depending on what I can scrounge up for spare parts.

The Ianto book states a minimum of a 6inch system for home heating. BUT he is talking about a thermal mass heater so that may change it slightly???

Soon I plan on starting a small barrel rocket stove (20gal maybe?) in my garage to prove that the system works before building what I plan on using in the house. Then I will build a 6inch or bigger for the house.

For me, I don't really care about the "thermal mass" and wish to extract the heat into the room more "instantaneously" as in the garage I'll only heat it when I'm in there either working on cars or building more rocket stoves! and the house is the same. Ianto also states in his book that houses are heated for the occupants, not the house itself, I"m inclined to agree...

I have a similar dilemma. I think that this type of rocket stove may be your best best since it is removable: rocket stove idea
It is what I'm looking at doing and still getting the benefits of more efficent wood burn. Plus since a rocket stove has yet to get a UL listing/rating, you will be able to remove it and the evidence of using it easily.

You oil burner idea interests me, and I'm sure others. It would be helpful if you would share your plans on it. I have been looking for a way to use the 30-40 gallons of used oil I have, and heat my garage with it.

Other people have done an outdoor rocket that heated water that was pumped to a radiator unit inside the house. Its on youtube somewhere, but seemed to be more involved in terms of building it.

I have a hard time envisioning exactly how your design will look when it is completed, but the plans look solid to me.

thanks chris, and martin for the suggestions; I'm not sure what I will go with here, but martin's suggestion seems tempting. I have some bricks and can make the chimney work I think. either way I'll post a full thread on whatever I end up doing. I hope the OP does like the thread he references with the old water heater and just pipes it into the fireplace; as he is renting and damaging the property would not be good.

Randy Metcalf wrote: I am living in an old single axle (dually) class A RV. i want very much to build a biomass stove in here next spring. I am thinking either use it for a couch or a bed. It seems obvious the the heaviest part of the stove works should be over the rear axles but am concerned about total weight using clay. I realize lightening it up may well make it less efficient, but would like knowlegeable feed back on this. I am also wondering about incorporating a rocket stove type water heater into this project.

Less efficient because it's lighter, maybe, maybe not. I'd think that you could raise it off the floor via concrete blocks, (fairly light) and then just do a shorter run for exhaust before it goes out a (window or side)? I mean how much do you have to heat an RV? a 8x??32' space? A small rocket stove should do that. It also seems that clay if spread out (i.e. raised off floor) shouldn't be too heavy. I'd just wrap copper tubing (1/2inch is cheap) around the barrel when you're firing it and it should heat enough for at least 1 hot shower/small bath. If you run the mass (i.e. 2 exhaust runs suspended on blocks, covered in clay) it should be enough to sleep on and shouldn't over tax the dually axle (less than 8,--- total i would think).

rob zos wrote:if i were to use rubble [bricks and concrete] as mass for my mass heater could it give off any poisonous fumes when heated

as long as the concrete does not have any rubber, plastic or other type of flammable or any galvanized metals, then no, it should not give off fumes. re-using rubble seems to be a great way to reduce waste, and still use it for good. I plan on reusing broken concrete block for my RMH, and I'll let you know if it gives any fumes off, but realistically what can it really give off for fumes?? Flammables give of fumes when burned and rocks, sand, cement shouldn't? A thought anyway.

Jeremiah wales wrote:On a Mass stove. Where are the ashes going? There have got to be ashes left over. Is there a clean out somewhere? I seem to be missing that poing in information about building one.
Thanks

the ashes are cleaned out just below the wood feed; normally people just scoop the ashes out or use a shopvac type setup. otherwise I'm sure you could build a tray. there is also another cleanout just after the barrel where the exhaust gases exit. that way you can clean out the ashes that may fall down the sides of the riser. Basically build the RMH with the idea of having to clean it regularly because ashes will accumulate.

What the OP was asking is if you can use ashes for insulation around the heat riser; which the answer is yes, you can use them to insulate the heat riser, although it is certainly not preferred for long-term use.