Robert Grantham

Thanks Thomas  ive written to him

Fox James wrote:Hi Rob, I have a few different styles of rocket stove on my youtube channel, some more basic than others but this style might suit your requirements ?

Hi James

Is this a batch box design you have made?

Hi all
Does anyone have contact to Matt? I wanted to ask him if his plans for the super hot j are avaliable in metric?

Glenn Herbert wrote:This page will give information for sizing a bell. It is intended for batch boxes, but can be converted to J-tube for an approximately 3/4 sized system, so a 4 1/2" batch box might use the same bell as a 6" J-tube. My experience with an 8" J-tube fits the math for a 6" bell

So Just to clarify Glenn do you mean that an 8" jtube should have the same size as a 6" batch box? So for my 6" it should be the same as a 4.5"? Do you think i could go with the measurement given for the 5" batch?

Ive calculated the inner surface area to be 5m2 which would be roughly 1m2 per wall including the top which im planning to make from metal. Does this make sense or have i miscalculated? It Just seems quite a small Bell to me.

Also as a seperate question ( and im sorry to be constantly picking your brain) is the Bell is ok to be made from standard bricks? Can i use normal mortar or is refractory motar needed?

Many thanks

Rob

thomas rubino wrote:Robert;
Here are some links showing my first RMH and its transition area being built.
https://permies.com/t/99389/build#819705
https://permies.com/t/74035/Draw-strong#615801

This is the best one
https://permies.com/t/61657/Flue-exhaust-transition-plenum-pictures

Thanks Thomas im considering bricking up over the riser and including the jtube in the Bell im a Total noob and yeah this idea Just seems more doable for me

Glenn Herbert wrote:

Another common method is to simply build the bell around the heat riser and dispense with the barrel. If you do this, you would benefit from installing a metal access panel in the bell for maintenance of the riser, and instant heating. A fault of some small bell RMHs has been the absence of a fast radiation source, thus making the users keep feeding it for hours until the space warms and then having the space overheat because there was too much heat stored in the mass.

Yes thank you i was thinking this. My other thought as you said would be to brick all the way around the jtube.. For quicker radiated heat into the room i thought to add a steel or cast Iron plate to the top of the brick Bell.

I thought this then might be Able to be used as a cooktop.. However considering the distance from the top of the riser it May not be hot enough

Hi Glenn

Thanks for the link.. Im having a job trying to calculate the ISA of the Bell based On a 4.5" system. It gives the value of a 5" at 3.7m2.. Is it ok to use this figure or do you think it should be slightly smaller? Will this make a difference?

The other issue im having at the moment is trying to imagine how the flue will exit my steel drum. Im planning to build a walker j tube 6" system and use bricks to surround the burn tunnel up to the base of the riser. On top of this ill use a steel barrel as a radiator...

My question is how to i vent from the system to the Bell? Is it ok to come out from the bottom of the barrel? I cant imagine there will be enough space for a 6" stove pipe to fit in the barrel next to the riser.

Also does the exit pipe from the barrel have to be level with the entry into the top of the Bell? Or can this be done with elbows? Im imagining the Bell will sit higher so the stove pipe will have to curve upwards.

Yeah i think i will go the Bell route. Ive plenty of bricks on hand. How big would you go for a 6" system? I was thinking to vent from the Oil drum into the Bell close to the top via a stove pipe.

The only thing putting me off is knowing how to size the Bell. I remember Reading that for a 6" you would need at least 6 meters of stove pipe to extract the heat via the mass. Im not sure what the eqivalent of this is for the Bell.

Also im not 100% sure the Best way of venting from the Bell to the outside.. Should the pipe be kept as short as possible?

Hello all

Im bouncing a lot of ideas around recently Just trying to conceptualise the stove.. At the moment i dobt have time to add thermal mass or a Bell but i hope to do this at a later stage.

So this would be a 6"system. Which would comprise of a steel j tube lined with ceramic fiber board both inside the burn chamber and riser. On the outside of the riser i plan to use either more fiber board or ceramic fiber blanket. The j tube will need to be lined prior to welding as accurately as possible.

For the burn chamber i plan to use fire brick splits for durability.

The radiator will be made of an Old steel central heating drum and then stove pipe fitted close to the base to a length of around 4 meters before exiting at the wall.

If anyone has any ideas or suggestions or sees any issues with this design please feel free to comment.

Thank you

Thanks Phil i was looking to make something similar to a liberator.. Metal outer Shell ceramic board riser and burn tube encased by steel in a jtube Type design  i still havnt figured out exactly how to do this though. Im looking for as many ideas as possible.

As I said i dont want to be messing about with mud at this time of year.. Its already cold and wet here. So ill lay out the pipe and maybe get some gravel/pebbles for around the stove pipe