steve allotment

Thanks Al No you are not misreading although I was not planning on using normal cement. We dont have much clay around here very sandy soil. Perlite over vermiculite fair do,s. I have just looked on ebay and found 25kg bags of fire clay for reasonable money not sure how much coverage a bag would give me though. I have seen the sawdust heaters great if you are outdoors not so good in my shed though. Had some success with the sawdust today though, I used a sawn off broom handle to ram it into kitchen towel cardboard tubes and put those in the RMH decent result. I have sacks of the stuff from cutting logs You would think it was gold the way I swept it up and saved it. Too good to throw away.

All in all I am very happy with my RMH, it always pulls well and frequently is white hot in the burn chamber making that lovely wooshing noise. Considering I do not have any insulation and only a 4 1/2 in exhaust pipe its doing really well. I cannot get my hands on anything suitable to insulate the Hr with so thought I could possibly wrap with tin foil then render with vermiculite and cement in thin layers and build it up to about an inch thick. Will the CV mix stick to the tin foil?. Todays R M H question answered wa,s can I fill the feed tube with sawdust at the end of the day and let it burn itself out? answer no I filled it thinking to myself there is plenty of oxygen in there and air can pass through it and all went well for about a minute and then some sciencey maths air pressure thing happened and it got sucked in and then spat out like a mini volcano! I was showered with sawdust and sparks. Lesson learnt. :

Hey Jake

Its in the manufacturers interest you use a full bag. Use as much as you need and seal the rest and store in a dry place will last you quite a while. You may find a few hard lumps in iit next time you come to use it but will still be ok.

Hi Bethany

How about building it on a reclaimed paving slab? thats what mine is on.

Thanks for that pointer Antone pretty good idea.

Hiya guys

As the subject states, came across this concept ont tinterweb watched a few vids and thought I had all the materials needed on my plot to build one of these. My cob is a little unorthadox consisting of sand cement and manure and is taking an age to dry out but is heading in the right direction. The burn chamber and heat riser is in the J formation and made from storage heater bricks. Which brings me to the first question which is, do I still need to put a layer of insulation around the heat riser will it make that much difference? The first problem that I solved thanks to this forum was to stick a vertical flue on the end of it as was getting some smoke back issues all solved now. The issue I have at the moment is that unfortunately as I am doing this on the cheap aka free, the only exhaust pipe I have is twin walled so no latent heat to warm the seating so have not bothered to make any yet, which leads me to my next question where can I source cheap pipe? in the US pipe seems infinatly cheaper than here UK so if any of you guys coud point me in the right direction that would be great.

Thanks Steve