Friday, 4 February 2011

The Steamie rocket oven: a quick intro

Three weeks ago it was my intention to blog our progress if not daily, then at least three or four times a week. But I'm not a natural blogger, and somehow 'blog entry' so often gets bumped onto tomorrow's todo list.

We're now halfway through our projected refitting time. I think we're still on track. It may be a bit of a scramble at the end, but then these things do always seem to be. In the meantime, I've revised my blogging intentions: I will try to write short, pithy posts in the hope that I will actually get around to writing them. Here's the first.

The basic scheme of our oven is to have three baking chambers ('decks', in baker-speak) heated by an efficient wood burner. Each deck is a kind of box-within-a-box, so that the burner can vent between the inner and outer skins. The outer skin is insulated so that most of the heat goes into heating the inner baking space. Here's a cutaway section:

The fire happens down around my shins (the fire doors are open in the picture, but close during use), and burns sideways along the horizontal combustion chamber. The hot gases then head up the internal chimney ('riser sleeve') to the bottom of the first deck. The gap between the inner and outer skins of the decks is pretty narrow (30mm) to transfer as much heat as possible.

We have finished all of the blockwork and screeded the hot faces We are now waiting for the screed to go off and for the steel decks to arrive from the blacksmith. 'We', I should add, currently means myself, Zillah, Dave (our neighbour, and boss of the building work - more of him later) and Zillah's brother, Guy. Guy is an architect, carpenter, CAD wizard and all round jolly good chap. He did the drawing above (as well as very many others) and has done a fantastic job coordinating materials. If you need anything at all doing to your house or any other building, he's your man.

Next: setting up the blocks.


  1. so is there a big temperature difference between the three decks?
    (it's bread hub catherine here, by the way!)

  2. Hi Catherine. As far as I know, no one has built one like this before so that's one of the known unknowns. I think the lowest will heat up quickest, and will in general be a bit hotter. The difference between top and bottom will probably even out a bit when the fire has been going for a while, though.

    Cheers, Matthew

  3. Scones in the bottom, meringues in the top. I'm sure that runs counter to granny-wisdom, but there you go!