Bambino woodfired oven (using recycled materials)
I had popped in there one day and found a particularly sturdy, bright orange frame with a wheel attached, kind of like a wheelbarrow frame and seeing as I had the trailor that day, decided to bring it home. I had thought of using it for a planter support but then my thinking changed and decided to use it for an oven support instead. Not knowing exactly how strong it was or how heavy the oven was going to be, it was a little bit risky, but with the possibility of a smaller oven tempting me, I was prepared to take that risk. It would really only be my time that would be lost if it didn't work out.
After painting it black, I positioned the frame up on some bluestone blocks to raise the (perished) tyre off the ground. The underside of the frame is bearing all of the weight. I had also picked up a sheet of corrugated iron and placed that onto the frame, securing it with screws. It was then edged with a round of bricks and filled with a very thin layer of vermiculite and brickies sand in the 'corrugations'.
The bricks that were to be the oven floor were then placed directly onto this surface and tapped into place with a rubber malet. A thin cement mix (4:1 sand to cement, watered down) was then poured around the gaps at the edges to secure the bricks into position.
The sand dome then needed to be made and the easiest way to do this is to use semi-circles of cardboard, joined at a central intersection. Sand is then packed into the gaps and moulded to follow the curve of the form. This part is really fun!
Half bricks are then positioned and mortared into place. The bricks can easily be cut in half with a bolster and (steel) mallet. The half bricks follow the curve of the sand dome, with the flat face of the brick alway laying as flush against the sand as is possible.
A piece of angle iron (from a bed frame at the tip), is hack-sawed to length and used as a support for bricks to pass over the flu opening. Measurements need to be super accurate, down to the millemeter in this case, as there was minimal space to work with, and I wanted to utilise every bit of it. The ideal height of the oven door opening is 60% of the internal dome height. My little bambino oven here has an internal diameter of only 550mm, and an internal oven dome height of 270mm. As you can see, they are tiny dimensions for a woodfired oven!
After the sand is scooped out, the oven entry begins to take shape which includes a decorative arch to match the one that the husband made on the big oven. The flue area is built up, with an opening left to accommodate the actual flue, which was also found at the tip. Two coats of vermiculite (mixed with cement and water) were layered onto the oven brick dome to act as insulation. This is one thing we skipped over on the big oven because we were in such a hurry to finish it, and while it still works great, I think it would work great for longer if it was insulated. The mix is also really hard to work with, kind of like packing on giant chocolate crackle mix that just keeps crumbling and falling away! Vermiculate is available at hydroponic suppliers (don't buy the tiny, overpriced bags from hardware shops).
Finally the flue is positioned and fixed into place with brick off-cuts and mortar. A layer of mortar is used to top off the vermiculite layer, and the oven awaits it curing. Amazingly our dubious frame is still holding up! I had wanted to cover the igloo shaped oven with volcanic rock, to match the big oven, but decided against it. I don't want to push my luck regarding the weight load. To read how the first firing went, click here.