Matt Jackson

Al. Thanks for the great info. Between your advice and the "Fake fire brick" thread, I feel like I will pretty much be able to avoid the biggest pitfalls in constructing these cook-stoves. If I get good enough results I'll be sure to share the photos here.

Thanks again!

I want to make several rocket cooking stoves for cooking meals/boiling water in times of an electricity outage.

I'm using 5 gallon buckets, but I might get some slightly larger open head steel drums. I made one from 50/50 portland cement and garden vermiculite and, as you can guess, it is very crumbly and basically falling apart after several firings. I want to move these guys around, store them in the garage, etc. and they need to be durable and ugly - so, cob is out.

Does anyone know which kind of commercial refractory castable would be most suitable for this? I am trying to find a balance of a castable which is abrasion resistant & tough, and also will not crack/break when under temperature. I would think the temperature inside would be relatively low (compared to pizza ovens, and kilns obviously). In the UK I have been looking at kiln suppliers which offer several grades which range in different temperature.. Guessing higher temp rating stuff = softer. I am also thinking of adding 2-3% steel needles to the castable for strength.

2nd question: What ratio of refractory vermiculite should I use in the castable? The stove is much more efficient when there is some insulation.

3rd question: Would I benefit from adding a layer of fire bricks at the bottom/half way up the vertical heat riser? Would this increase the efficiency and also increase some abrasion resistance for feeding the fuel?

Many thanks if anyone can help me with these question marks. Cheers!

great Roy, again, thanks a lot.

Thanks for the info Roy. That's a bugger but everything you said makes perfect sense. My dream of caking metres of flue in cob will have to wait!

Do you have any idea if making a little freestanding fireplace for the stove, (covering the back, sides and top) of thick cob, would be detrimental to the cast iron, or interior of the stove, by overheating the metal?

I'm not talking about plastering cob all over the stove, but making a very tight-fitting little cob housing for the stove?

Hello!

I'm making a moving to SW France from England to work as an apprentice on a cob/strawbale house build. My girlfriend and I are staying under canvas in a corner of a grassy field at the work site.

The plan is to build a yurt over the summer, ready in time (hopefully) for the Christmas, but until then I want to work out a way to intelligently heat a 6m 12oz canvas 'bell tent'. It will sit on a raised (a foot or so), flattened earth platform.

I had an idea to place a 'cleanburn' Morso Badger 5kW cast iron wood burner in the middle of the tent, and then snake the flue horizontally- cobbing the flue over, perhaps into a bench and/or bed headboard. I'd like to cob over the entire stove, but it's on loan.

The tent has an attached, heavy canvas groundsheet - and I don't want to go slicing and dicing it up as reselling it will help fund the yurt. On top of the groundsheet i'm thinking a plywood form, with insulated bottom layer, covering the entire footprint of the horizontal flue.

Could I capture & trickle release a good amount of escaping heat this way? Can you forsee any problems with this?

Thanks
Matt