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The Justa Stove A Step by Step Construction Guide
Drawings and Text by Sebastian Africano, 2006 Based on Designs Used and Developed by: La Asociacion Hondurena Para el Desarollo (AHDESA), The Aprovecho Research Center, and Trees, Water and People
- Brick and Adobe: 7 Adobes and 25 Bricks
- Brick and Blocks: 7 Bloques and 25 Bricks
- All Brick: 70 Standard Bricks
- Mud Mortar and 1 Bag of Cement
- Three sacks of River Sand
- 60" Length of 3/8 Rebar
- 1 Sack of Sifted, Dry Wood Ash
- 1 Milk Can, Coffee Can, or paint can with the bottom cut out and with metal lid
- 2 Wood Wall Studs 1"x2"x72"
- Handful of Small Nails
- 4 Strips of Cardboard 2"x22"
- 3-5 Brick Tiles (see below) 11"x11"
- A Ceramic or Metal Flue Shelf - Permits air flow under fire
- Always use a Fuel Shelf
- Always chop firewood down in size for best results
- Always use dry firewood
- Once a week, tap chimney with a stick to keep it from clogging
- Once a week, dust the soot off the bottom of the plancha
Build the stove body from either adobe, brick or cement block, guiding yourself with the measurements shown in Drawing 1. The stove in this example is made of adobe with a mud mortar
Lay the milk can, with the bottom already cut out, on a little bit of mud in the space indicated by the drawing. Leave the walls of the stove leveled with a constant height of 11.5"
Place a bed of mortar over the milk can and lay a half brick on top of it. Stand a brick against the opposite wall and rest two 22" pieces of rebar on top of the prick so that they bridge the width of the stove. The standing brick should be cut so that the rebar pieces lay level.
Build a brick wall, 11.5" in height and 24" from the front of the stove, leaving a 4"x4" hole in it where indicated in the drawing. Next, seal the space left over the rebar bridge with two bricks, leaving a 5"x5" space on the side of the stove opposite the milk can
Build a second wall, of either ceramic tiles or three thin bricks, upright in mortar and at 1.5" from the first wall. The second wall should be 1/4" higher than the first. This is the only wall which is higher than the rest.
Build the combustion chamber in the manner indicated, sealing the joints between the tiles with a very wet mix of mud.
The important point is that the entrance to the combustion chamber is centered, and that it's height is 1/2" lower than the walls of the stove.
Over the 5"x5" hole left towards the rear of the stove, build a brick tower to lift the chimney, as indicated in the drawing. Next, seal the front wall of the stove to create teh cavity which will hold the insulation. The entire structure should be solid, leveled and square.
Fill the large cavity left in the stove with dry, sifted wood ash. Fill ash to the height of all of the walls - ncluding taller walls.
If you are short on wood ash, put the finest ash at the top of the pile.
Rest 2, 6" lengths of rebar diagonal across the gap in the chimney stack.
Center the plancha over the large cavity and make certain that it sits flat on all walls.
The sacrificial plate should be over the combustion chamber.
Next, build a frame around the crown of the stove with the framing studs, and level the frame with the plancha.
Frame the plancha with the strips of cardboard, and fill the space between the two frames with either cement or a damb, compacted mix of earth, sand and construcion lime
Rest a chimney tube on the two diagonal lengths of rebar and seal it in with earth or cement as shown in the drawing.
Build a 20" long, U-shaped sheet metal tray to catch wood ash falling from chimney - insert through can.