Post by Rinchen on Nov 19, 2012 3:13:37 GMT -8
Yes it heats the place very well! Even upstairs stays warm enough with it. I built part of it straight onto the concrete floors which accumulate heat. Close to the bench you can feel that heat through the wooden laminate floor. The door construction can be seen in the Sketchup 3D model. It was a bit of an experiment and isn't built to be durable, yet its still functioning well. I had the glass already which I bought second hand. The firebox itself was also build as a test so I decided to get cheap material that would be quick to build with. I got a bit bold on the material choice and went ahead to try AAC (1). This stuff can be bought cheap here, its easy to work with, has insulation properties and some have use it to build forges. So I thought what the heck lets do it. For that amount of money its worth a try. The 'mouth' of the tunnel, basically the backwall of the firebox is mainly constructed with chamotte bricks though and the P-channel facing stone is a very hard 3cm thick chamotte 'pizza oven' stone which was very difficult to cut.
As the foundation I used 7cm thick AAC and lined it with a layer of 2cm Raku clay which is not too expensive and handles heat shock very well. The sidewalls are also 7cm AAC and I brushed a thin layer of Raku clay onto it. First wetted the AAC very well because its absorbs water and the Raku clay was made smooth by mixing it with water in a bucket using a cement mixer in a power drill. The sides and the ceiling are loosely stacked using some mineral wool as a gasket.
The door is also cut out of two pieces of AAC (split vertical) 5cm thick and on the back painted with a layer of the Raku clay. The front I cut out from a sheet of alumininium 1mm thick and that is held in place with aluminium L-profiles screwed into the edges of the AAC. The sheet also holds the glass into the door. On the edges of the inside I used iron L-profiles, also screwed into the AAC. Because of the expansion of the profiles which are screwed into the AAC the AAC cracked horizontally and so its four pieces now, but since that its holding together pretty good. So not a perfect solution for a door, but it works for now. I am still thinking about a new door to come later.
I am really surprised about the AAC, it holds very well as a firebox liner. The slanted side to make the V on the bottom are also cut from AAC and I decided not to put Raku clay on these. They are in direct contact with the mad-hot coals, yet they are holding up just fine. You can see some cracking, but thats ok. Just dont use it as part of a load bearing construction.
(1) en.wikipedia.org/wiki/Autoclaved_aerated_concrete
