The proportion of sand and clay for laying the stove

Firewood burning temperature - 500-1050 C. Not every stone and mortar can withstand such a load. The furnace is built from refractory fireclay and clay bricks, and instead of the usual cement one, a clay composition is used. The proportions of clay and sand in the mortar for the oven must be strictly observed, otherwise the masonry will be fragile, and the oven short-lived.

Accessories for work

To make a masonry mixture, you need a minimum of tools and materials:

• clay - red, rather oily, plastic;
• sand - river quartz and fireclay;
• water - ordinary, but clean;
• shovel and trowel;
• buckets, troughs, barrels for preparing clay and mixing mortar;
• any mixing device.

In the store you can buy ready-made dry mortar for the construction of ovens. In this case, only water, a bucket and a mixer are needed for cooking.

Selection and preparation of sand

Different sands are needed for the construction of different parts of the furnace. The highest combustion temperature is observed in the combustion chamber. A mixture of clay and chamotte sand is prepared for the firebox. It is made by crushing fireclay bricks. In fact, it is crushed clay after low-temperature firing.

For laying the hull and chimney ducts, a solution based on clay and river sand is taken. Its difference is high uniformity, medium and small particle diameter, roundness of shape. River sand is very clean, does not contain mechanical impurities and practically does not include organic additives. It is used in the manufacture of plaster: the store is looking for material with the appropriate markings.

Since the sand extracted from the bank or bottom of the river includes different fractions, it must be sieved before work. The solution requires a medium and small fraction: large particles lead to strong shrinkage of the solution when it dries. In addition, the material must be rinsed. To do this, you will have to make a device from a metal pipe with a tapered end.

Clay fat level

Clay is a micro-grained mineral of complex composition. Differs in elasticity, water resistance, good adhesion to stone. For the masonry mortar, take red clay. The material is pre-cleaned.

The main characteristic of the mineral is fat content. This parameter determines the quality of the future stove. Excessively greasy, when solidified, actively evaporates moisture and cracks. Over time, such a solution crumbles. Overly skinny material is not flexible enough and does not hold bricks together.

Before kneading the clay for the oven, determine its fat content. There are several ways:

• A handful of dry material is soaked in water and kneaded in a fist. If the composition has taken the consistency of plasticine, the clay is oily. If it crumbles, she is skinny.
• The mineral is mixed with water - for 0.5 l, 100–150 ml of water, knead and make balls 45–50 mm in size. One of them is flattened into a cake. Crafts are left to dry for 2-3 days. If after 3 days cracks have formed, the clay is too oily. If you drop a ball from 1 m to the floor, and it does not break, the fat content of the mineral is normal. If she breaks, she's too skinny.
• The most accurate way: a ball is made of clay dough and squeezed between two plates until cracks form on it. By their size, the mineral is judged.If the ball crumbles even with slight compression, it is skinny. If fine cracks appear when the ball is compressed in half, the material is greasy. Clay is considered optimal, the balls of which crack when flattened by 1/3.

Both oily and skinny clay can be applied with the correct amount of sand.

How to establish the quality of the solution

Only normal solutions are suitable for laying a stove in a house or in a bath. Fatty ones crumble after hardening. And since the oven is actively being used, this happens very quickly. Lean solutions do not guarantee wall strength, which is unsafe.

Since it is difficult to accurately measure the indicators of materials without instruments, they resort to another method. Mix 5 solutions with different concentrations of sand and clay and determine the suitability of each composition. The technology is as follows.

1. Prepare 5 equal portions of clay. The first is left unchanged, 10% of sand is added in 2 sample, in 3 - 25%, in 4 - 75%, and in 5, clay and sand will be in equal volume.
2. Add enough water to each portion so that a thick dough is obtained from each sample.
3. Balls 4-5 cm in diameter and plates 2-3 cm thick are sculpted from portions. Leave for 10-12 days to dry. The sample should dry in a closed room at room temperature.
4. If the balls and plates crack during drying, the composition is oily, more sand must be added to it. If the plates are colored, and the balls break when they fall, the mixture is lean, you need to put more clay. If the clay handicraft does not crumble when it falls, the solution has the required fat content and plasticity. When making a mixture, sand and clay are mixed in the same proportions as in this sample.

At the stage of making large portions, attention is paid to the density of the composition. If gaps remain when the trowel is carried out over the surface, the mixture is too thick. If the traces from the trowel are quickly filled with liquid, the mixture is liquid. She needs to settle, and drain the excess water.

In the right solution, the trowel leaves a trace without washes, and the grooves swell very slowly.

Variants and technology of solution preparation

For the masonry of stoves, the proportions of clay and sand are selected, based on the characteristics of the materials available. If the clay is oily, the proportion of sand is increased; if the clay is lean, less quartz. As a result, a good composition for the oven is obtained empirically.

How to mix the solution correctly

Prepare the masonry composition according to several "recipes". The technology of the most accessible method:

1. The clay is soaked for 2-3 days in a wooden box or in a tin trough. After 3 days, put sand and, putting on boots, trample the mixture until all the lumps are broken.
2. Then the solution is kneaded with a rammer and hands to crush all small lumps.
3. A normal mortar suitable for building a kiln slides off the shovel, but does not drain. If you put a layer of 3-4 mm between 2 bricks, after 5 minutes the stones will not come off each other.
4. If the mixture is too greasy, add sand - no more than 15% of the volume, and repeat all the manipulations.

The following method is recommended if normal clay is used.

1. First, they construct a wooden flooring with sides - a firing pin.
2. Clay is laid on the firing pin in layers and moistened with water. When the material has softened, it is turned over, raked into piles and beds, leveled and flogged into chunks with a shovel. All these operations are repeated until the solution becomes completely homogeneous.

High uniformity is achieved more quickly when using method 3. It is efficient but also time consuming. Clay for soaking is piled in barrels, then the mixture is filtered through a sieve with cells of 3 * 3 mm. Sifted sand is also added to the composition. If the consistency is too thick, dilute with water.

Sand to clay ratio

The volume and ratio of ingredients vary widely.The optimal combination is the ratio of sand to clay 1: 2 or 1: 1. The volume of water is approximately ¼ of the amount of the mineral.

In fact, the proportions are determined by the fat content of the mineral. With a high fat content, 2 parts of clay may account for 4 parts of sand. If the material is lean, the proportion of sand is halved.

Checking the quality of the solution

The quality of the solution is checked by a variety of methods. The most accessible is the draining of the material from the shovel, which is performed right during cooking.

The tactile test gives a reliable result. The normal composition creates a rough layer on the fingers. Oily forms a film, sticks to the palms. Skinny leaves no trace.

You can visually assess the quality of the mixture using an ordinary wooden stick. After immersion in a normal solution, traces and particles of the mixture remain on it, in a greasy one - a dense film. The thin solution does not leave traces, the wood remains wet.

The safest practice is to lay a layer between bricks. If the mortar is thick and greasy enough, after 5 minutes the bricks do not come off from each other. If it is oily, this effect is observed even when a very thin layer is applied, no more than 2 mm. If skinny - the bottom brick will fall.