Step 3 Base layer, bottom slab, firebox and riser
The firebox
It's best to build the firebox on a sturdy work table. First, make a transport board from a piece of 18 mm plywood or other sturdy plate with which you can transport the core. Fix a batten on both sides, in such a way the bottom bricks just fit in between.
About gluing with Moviset
You are going to glue the core together with Moviset or a similar refractory glue. Open the Moviset bucket and pour off the covering liquid. Stirr well until it has the same consistency throughout. Add a little of the poured-off liquid if necessary. When you're done gluing, cover the remaining glue with a layer of water before putting the lid on.
The parts to be glued should be thinly but completely smeared on both sides, about half a millimeter thick. At 15º Celsius, the glue has hardened after about 24 hours. It takes much longer at lower temperatures.
Bottom bricks
This building description assumes firebricks with measurements 220 x 110 x 30 mm and 220 x 110 x 60 mm.
The front three bricks have a height of 30 mm, the rear two are 60 mm high.
Measure the length of the five bricks including the 1 mm space for the glue, and shorten the fifth brick to obtain a total bottom length of 537 mm.
1. Transport board with bottom bricks
2. Walls
3. Top bricks, port, 45º bricks
Location of the stove
Base layer
At 220 mm from the wall, glue the exhaust block and the two 480 x 200 mm pieces to the two tiles and to each other. A space of 25 mm is left on both sides. The opening for the flue pipe is now exactly in the right place. Use a carpenter's square and make sure it's level. With clamps you press the parts against each other. If necessary, correct with a clamp (see photo).
During the first heating period, condensation will come out of the flue. To collect this, place a (baking) tray under the opening. A spout ensures that the water flows smoothly into the tray. For example, you cut it out of a tin can.
Bottom slab
Glue the two parts of the bottom slab together; at the same time you lay the whole on the base layer, using cement mortar (1:5). It's important that the top is flat and level.
Spout
Condensate tray
Gluing the firebox
Butter the bottom bricks with glue and place them on the transport board. Using a large clamp, carefully apply pressure across the bricks until the glue begins to squeeze out. Make sure the bricks are level. Let it dry.
Now cut bricks for the walls of the firebox, in such a way they fit on the three bottom bricks (332 mm). You adjust the top layer in such a way that the total height of bottom bricks, walls and top bricks is
353 mm.
Next is adding the port bricks.
If the bricks are exactly 220 x 110 mm, the vertical port bricks will be 183 x 90 mm, as drawn in the SketchUp file. But if the bricks are slightly larger or smaller, those sizes must be adjusted. The most important thing is that the port opening will be 183 x 42 mm.
The vertical port bricks are glued to the 4th bottom brick, as well as to the walls. On top of them you glue the horizontal port brick. Make sure everything is flat, square and level.
Next glue the top bricks in place, see the picture. On the inside of the firebox, glue on 30 x 48 mm cut bricks. They form the 61 x 30 mm slot that accepts the secundary air duct. The 45º chamfered bricks are glued on top of them. Fill any gaps with glue.
At the front, 4 mm of space is kept open for the metal plate that sits at the front of the floorchannel.
4 mm space
The riser: cutting and gluing insulation bricks
48
420
180
820
480
155
600
820
220
25
600
200
400
250
195
90
From the opening in the ceiling through which the flue goes, draw a plumb line to the floor. At 42 cm to the left and 18 cm to the right of that point, draw a line. The first two 40 x 60 cm concrete tiles will be placed between these two lines. You fix them on the floor with cement; the ratio cement / sand is 1 : 5.
48
34
34
The insulation bricks are 64 mm wide, which should be reduced to 57 mm. You can easily saw them with a handsaw with hardened points, but sawing a narrow slice is difficult. Then a saw guide offers a solution. Make it out of timber, see the drawing.
If all goes well, the tops are flush.
Take a brick and draw a line 34 mm on either side of a corner. Draw the diagonal line at the short end and saw the brick lengthwise (see drawing). Do this at another corner as well.
You now have two triangular strips that will be glued to the inside of the riser (see drawing).
Now coat the inside of the insulation bricks with a thin layer of Moviset.
The third layer
Of the third layer, the two whole bricks have a notch. It will be approximately 57 x 59 mm, but measure the exact size in the work, taking into account the 1 mm Moviset. A brick cut exactly in the middle completes the layer. The inside of the front half-brick is flush with the port.
Coat the inside of the layer with Moviset.
The upper part
You can already glue the upper part of the riser together. Coat the inside of each layer again with Moviset. Only later in the building process the upper part is put on top of the bottom part.
231
23
75
164
101
3
18
Coat the inside with Moviset
183
42
537
353
220
332
Download here the 3D SketchUp file
