go about this project, this guide only serves as a general idea – so modify your build according to your tastes and needs.
Thanks to Brack & Ban Jhankri for their help in this project!
The basic principle stays the same, what is most important is to maintain a good air flow
for the fire to sustain itself and it’s heat to pass easily round the whole system.
Geysers are ideal for use as an oven as their metal is thick, this geyser has been completely stripped of its insulation
A good burn will ensure no residual insulation is left, this also sterilises the metal – leaving only the water sediment and residue inside the geyser
MAKE SURE AIR CAN ESCAPE THE GEYSER DURING THIS PROCEDURE
A lid can be cut out by a hacksaw or electric saw from the geyser itself
Fixing a hinge to the oven lid, welding was used in this case
Digging a fire pit and lining it with scrap metal in order to conserve heat
A metal barrel lid was used as the base – in this case I did not wish a direct flame to touch the oven, this makes an ideal slow cooking oven, (for a quick heating oven suspend the geyser on horizontally placed metal poles)
The hole in the barrel lid is the start of our chimney!
A thin layer of soil and broken glass was placed on the barrel lid (broken glass conducts and retains heat for a very long time)
Geyser now placed on top of this base, and the foundations laid out – care must be given to separate the chimney entrance from the soil and stones which will now be placed on top of these foundation
Now layer upon layer of soil and small stones will be placed upon the foundations – these will encircle the geyser and contain the heat produced effectively.
For a quick heating oven a heat resistant metal net can be encircled around 1″ away from the ex-geyser and the stones & soil be placed on top of the net instead – (in this way the surrounding air would still heat up the oven, escaping through the chimney)
2nd level of ‘layering’ – the air vent from the fire pit might seem like it’s covered – however a flat stone is covering the vent so the soil will not seep through it and block it
whole structure taking shape :
the soil & stone layering has been finished, a test has been made to check if the vent and fire pit are working correctly – in which they did!
tomorrow a thick covering of ‘cement’ composed of soil and water will completely cover the whole structure
lighting the fire pit..
smoke successfully escaping through the air vent
a peek inside the fire pit: the fire is gathering directly under the base, it is burning easily – this is the most important thing as it indicates a good air flow
The Morning After..
the oven still retained its heat from the couple of logs that were burned in the pit, noting that all has worked well – the ‘soil cementing’ may now commence.
soil cementing is important to avoid the heat and hot air from escaping the system
oven is now nearly ready!
another layer of stones can be placed on the structure so the winter rains will not wear away the soil covering – or a layer or two of plastic sheeting is also enough for this purpose
the chimney can also be elongated to create a sort of suction which will aid the fire – in my case I preferred to leave as is, in order to place a pan/cooking pot upon the base of the air vent