A) If the oven is going to be installed outside, prepare a supporting base in concrete that is perfectly horizontal and secure, in order to avoid subsidence in the ground caused by the weight of the oven. It is not advisable to use slabs in the cement base.
B) To assemble the oven you will need to prepare a mortar mix of 80% sand with 20% lime. It is absolutely forbidden to use high resistance cement, rapid set cement or tile adhesive or similar because it does not allow for the thermal expansion of the oven parts that are in contact with the heat and could lead to cracks developing due to heat stress.
1) Build two walls in brick or breeze block (as in the diagram) 13cm thick for the oven support. Decide what height would be best for the fire base (about elbow height).
2) Build a reinforced base or in some way support the oven underneath, taking care that it is perfectly level and flat.
3) Form a layer 7cm thick with perlite, vermiculite or fireclay mixed with 30kg of ciment fondu and add water until you obtain a semi-dry mix that spreads out uniformly on the surface corresponding to the base of the oven.
4) Place on the oven floor, checking that it is level and that the individual parts fit together perfectly, and make level not allowing for any difference in height.
5) Join together the parts dry taking care to fix metal staples (4mm diameter), drilling the oven sections (base and other parts). For this the staple should be bent to a U-shape measuring 15cm x 3cm.
6) Insert a flexible or rigid flue of 20cm or 25cm diameter, depending on the model of oven purchased.
7) Coat the sides of the oven with 10cm rock wool fire blanket insulation of 100 density. Hold in position with metal cable or, for best results, use chicken wire.
8) Render over the rock wool insulation with a lime mortar mix, as described in point B.
9) To complete the oven you can put a prefabricated refractory arch around the mouth of the oven (optional).
It is important to emphasise that the oven must always have a protective render if it is to be installed outside (garden, patio) as opposed to inside (kitchen, restaurant, etc.). Surrounding the arch of the oven mouth put in a silicone expansion joint between the arch and the render. This will allow for the oven’s expansion and contraction.
48 hours after installation light a small fire next to the three sides of the oven spread out from the arch daily for three days, changing each side the position of the fire (maximum ½ kg every time). After doing this for the next two days increase gradually the fire’s intensity until the blackening of the oven vault and until the desired cooking temperature is reached. Don’t strike on the oven base with a shovel, but clean it with an appropriate scrubbing brush.
For good heat retention the manufacturer advises shutting, after lighting, the mouth of the oven with the proper steel door complete with thermometer.