Cornish Nathan

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since Oct 14, 2009
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Recent posts by Cornish Nathan

Firstly, thanks for taking the time to respond with your extremely valuable advice, it's very much appreciated.  At the moment I'm just finding out what might be feasible with the space, time, budget, skills, etc, that are available to me.  This is just the research phase.

I fully understand your dismay about excited yet inexperienced people doing more harm than good to the bigger picture, despite the best of intentions.  Please rest assured I will be working with others that do have experience of both cob and rocket mass heaters on the delivery of this project.

If, for whatever reason, I cannot show rocket mass heaters in the best possible light then the project will not happen.

thanks again, Nathan

11 years ago
Firstly, thanks so much for your really informative replies, you've really given me lots to think about and consider.  Unfortunately I can't send any photos today as I have no camera but the issues you have raised I will try to cover so you get a better picture of what I am dealing with over here.

The stage is very strong structurally so the weight of both stove and bench will not be a problem.  Your description of it looking like an aircraft hanger is very much the case, it's approximately 80 feet tall and 200 feet square, completely covered but with clear open space between roof and walls allowing the breeze to blow through but keep the rain out.  Due to this amount of permanent ventilation I think it virtually impossible to heat the air space so I was thinking that the bench's primary function in this would be as a 'butt warming little kitten'.

The amount of ventilation in the tent should hopefully help with getting the exhaust out of the tent as there is plenty of room above to let it dissapate.  I was hoping to have the chimney visable and open vertically so the visitors could see the lack of smoke.  Would a 10 feet vertical stack be sufficient?

I like Ernie's idea of a smaller wider bench with 3 passes and a 6'' system built within a frame and filled with perlite and clay.  Is there a reason for the 3 passes?  I was thinking of doing maybe 2 passes, like a big U-shape and have the chimney return close to the stove.  Also what ratio of clay to perlite would you use?

Another question, could I use the instructions in Ianto's book for an 8'' system but with a 6'' tube or would this overload it? 

Also what temperatures could i expect within both the stove and also the bench?  My Health and Safety people will be very interested in this?

Unfortunately my budget for this does not quite stretch to flying you guys over here to help with this, but you would be made very welcome guests should you ever find yourselves this way.  I love the Santa hat tipi idea, I'll suggest it for next year.

Once again thank you so much for your speedy and knowledgable replies, this is a great site.

Cheers all, Nathan

There is a space of just under 30 feet between my proposed bench and the ice rink so heat transfer should not be a problem, there is also drainage in between.

11 years ago
The wooden floor is actually a large outdoor-stage under the cover of a huge permanent tent structure.  The stage is supported via massive metal posts and metal scaffolding onto which is a sub-floor of laminated ply-wood, topped off with plywood.  Underneath all this is a lake!

The owners of the stage (my bosses!) definitely do not want to lift the floor so everything must sit on top of the ply wood, must protect the floor from the heat generated and be able to bear the heavy load of brick and cob!

The rest of the stage is being transformed into an ice-rink for the winter season and the whole thing will only last until late February.  So what I'm really trying to do is to build a Rocket Mass Heater with possibly up to 8 metre cob bench to demonstrate to our visitors (and my bosses) what these fabulous contraptions can do.  Hopefully after this winter trial I will then be able to build a permanent Rocket Mass Heater in another location, and NOT on a wooden stage.

We're a major environmental/educational visitor attraction and will expect between 150-200 thousand people to come to see, play and learn stuff with us this winter.  My intention is for a large percentage of these people to 'warm their butt's' on the bench whilst I explain to them the benefits of Rocket Stoves, Mass Heaters, etc.  I'm also keen to be warming soup or maybe even roast chestnuts on top of the barrel.

I've been demonstrating the Winiarski Institutional size Rocket Stove for the last 2 years here at Eden with great results, and this would be a fantastic development of all things Rockety!

If you'd like to see more about Eden go to  It's a truly inspirational place.
11 years ago
I'm looking to build a rocket mass heater above a suspended wooden floor and would like to know how to go about insulating the floor from the extreme heat that the stove will generate.  I have Ianto's book with a brief description of one technique but would like a little more guidance on this.  In particular how to mix and set a slab of insulating mass that is also capable of supporting the weight of the stove.

This stove is going to be used to demonstrate the benefits of Rocket Mass Heaters at the Eden Project, Corwall, England.

11 years ago