Typically take one part of the clay and the same sand or in a 1: 2 ratio. The amount of water required is approximately 1/4 of the clay volume.
Normal fatty and plasticity solutions have sufficient strength. Hyd, they do not crack, do not give a large shrinkage and are little painted from the seams.
Brick raw - best Material For the preparation of the solution. It is carefully selected composition of clay and sand. Such clays require only wiping with water and careful kneading lumps. Waters take so much to get the solution of the right density.
Any clay before cooking should be checked. For this, they take five identical portions of clay at 0.5 or 1 liters. They add water in such quantity so that it turns out cool clay dough. The first portion is left in its pure form, 10% of sand add to the second, to the third - 25, to the fourth - 75 and to the fifth - 100%. If the fastened clay is fat, then the amount of sand is taken for the second portion of 50%, for the third - 100, for the fourth - 150 and for the fifth - 200%.
Each portion is individually stirred well with the addition of water until the solution becomes completely homogeneous and the moisture will not be distributed evenly throughout the mass. After that, sand and water are added to the prepared portions of clay, it is thoroughly mixed, getting cool dough. After receiving a portion of the solution, proceed to their test.
From the prepared samples of the solution produce two to three balls with a diameter of 4-5 cm and two or three cakes from the same balls with a thickness of 2-3 cm. They are dried in the room without drafts. The solution is considered suitable if the dried balls and pellets are not cracking, and the ball in the fall from a height of 0.75-1 m is not scattered on the floor. If the solution is skinny, then the ball is crumpled when the bold - cakes and the ball are cracking around the edges. Check the solution and in this way. From the prepared portion, the balls with a diameter of 4-5 cm roll and, by placing them between two planed skimps, pressed them until cracks are formed on the ball. Depending on the magnitude of the flattening and character of cracks, they judge the plasticity of the clay solution.
The ball of skinny clay with a slight naughty on it is scattered into pieces, and large cracks are formed from clay with low plasticity with a small plasticity of its diameter. If you squeeze the ball of medium plasticity clay, there are cracks of the same form on it, but only on 1/3 of its diameter. Thin cracks on 1/2 of its diameter are formed in high-pile clay solutions when compressing the ball are formed.
To prepare a clay solution, a solution of medium plasticity, skinny and fatty - are unsuitable. In the first one must add fatty clay, in the second - sand.
When checking in the second method, instead of balls, from the same mass roll over the arms of the flavors (sausages) of the same thickness (1-1.5 cm) and a length of 15-20 cm. Then they are stretched and bend in the form of a ring around a round stick or a rolling pin with a diameter of 4-5 cm.
The flagery of skinny clay is almost not stretched and gives an uneven gap, and when flexing around the rill, there are many cracks and breaks. The firing flayer of medium plasticity (brick clay) is stretched smoothly and breaks, when the thickness at the break site reaches 15-20% of its diameter, and when flexing in places, the bend is formed small cracks.
The harness from plastic and high-pile clay smoothly stretches and gradually will be thinned, forming an acute end to the break place, and when flexing does not give cracks.
Testing with the method of crushing the ball, stretching and flexing the flashes make it possible to choose a clay of suitable plasticity suitable for the manufacture of raw bricks and a clay solution used for masonry furnaces. Such a solution is well withstanding heating to 800-1000 "C, does not lose strength and does not allocate harmful evaporation. From heating and cooling, the solution changes its volume equally with the brick and does not upset the masonry, saving it without cracking.
Determining the corresponding composition of the clay solution, proceed to its preparation.
The amount of solution required for the construction of the furnace is sufficiently large - from 1/13 to 1/10 of the furnace volume, counting on outdoor size. On average, it is believed that 100 pieces of clay bricks should be from 2 to 2.3 buckets, sand - from 1.5 to 2 buckets. The greater the brick than the cleaner of the clay solution and the thinner of the seams, the less the solution will go to perform work.
The chimney must have thin seams. To obtain thin seams, the materials individually sieved or the solution is filled through a sieve. When polling the solution is additionally mixed again so that it does not remain bustics and it was completely homogeneous.
To sieve sand and dry binders (gypsum or cement), sieve with cells from 1 × 1 to 1.5 × 1.5 mm are used, and for sifting clay or polling the solution - with cells at least 3 × 3 mm.
Preparation of the solution. Sand sieved through a sieve. The clay is put in strong dishes, most often in a barrel or box, poured with water, knead large pieces, mix well and leave on one or two days. It should be noted that the longer the clay is in water, the more it is better to twist and it becomes plastic. Mocking clay is still stirred and filtered through a sieve into another dishes, getting a sour creamy mass. Preparing the desired amount of clay, proceed to the preparation of the solution. At first, it is recommended to pour the sand layer in the box, then pour clay, fall asleep with its second sand layer and mix thoroughly. For complete homogeneity, the solution is filled through a sieve.
A well-mixed solution is considered when the grungy layer of sand is felt between the fingers, and not a slippery film with separate sands in it. A normal cooked solution is similar to a thick sour cream, it easily slides from the steel shovel, but does not spread through it. On such a solution and perform chimel Masonch.
Machine clay on one or two days, kneading. Then on a wooden shield-board (on the ground worse) pour a divergent amount of sainted sand. The length of this bed is made a groove and fill it with the necessary amount of clay. They collect sand from the edges of the beds, fall asleep to them clay and all shock. If the mass is thick, then some water is added to it. In the process of mixing, they are trying to split separate lumps, bringing the solution to complete homogeneity. Then it is crushed into a narrow long bed with a width of 300-350 mm wide and a height of 200-250 mm and begin to the so-called "cutting" solution with a wooden oars or a shovel, causing shocks across the bed. They hit the shovel so that it reaches the wooden flooring and every blow came next to another, as if cutting off a slot of the solution. This process is repeated multiple times until full mixing of clay with sand and simultaneous kneading of all clay clots. Along the way, pebbles and other impurities are removed. After that, the bunch again shuffle, crushed and sculpt again, repeating this operation 3-4 times.
When all lumps are broken and the solution becomes homogeneous, water is added to the dough thickness and stirred again. Finally add water to the desired density before starting the masonry in the workplace.
In the thus prepared, various lumps, large grains, small pebbles that have to be deleted during operation remain in prepared. Seams on such a solution can be a thickness of about 10 mm. It is better to skip it through a sieve with cells at least 3 × 3 mm.
Clay solutions have a low brand: in a dry state - from 4 to 8 kgf / cm2, in a wet - up to 2 kgf / EM2. To increase the strength of the solution, and consequently, the furnace masonry, one bucket of the clay solution, you can add from 100 to 250 g of the cooking salt or not more than 3/4 liters of Portland cement. (From a large amount of cement, the formation of cracks in the seams of masonry is possible.) Cement not only increases the strength of the solution, but also gives it high plasticity and convenience in work.
Salt is pre-dissolved in a small amount of water, this water is added to the clay solution and everything thoroughly mixes.
The cement is inducing to the preparation of liquid sour cream-like mass, which is poured into the clay solution and are thoroughly mixed to fully uniformity.
Solutions with salt and cement are sometimes applied by hand, but it is preferable to work with a cielma or spatula.
Ideally, the clay solution and brick almost do not differ in their composition and are able to carry heating more than 1000 degrees. The quality of the clay for the solution is determined to the touch, and perform the masonry with the thickness of the seams of the clay solution is 3-4 mm. With thicker seams, clay between bricks does not withstand high temperatures and crumble, cracks are formed. For furnace work - the smaller the clay in the oven masonry, the higher its quality.
It is believed that the strength of the clay solution can be increased with the help of all sorts of additives. For example: by 10 kg of clay - 100-150 g of a cooking salt or 1 kg of cement. However, our great-grandfathers were unlikely to use the cement, and their ovens and walls stood at a hundred years. If the composite parts are correctly selected, the clay solution does not require any additives, and all sorts of recommendations are only a substrate.
The clay solution for masonry must be plastic, moderately fat, or, as they say, normal. The fatty solution, hidden, decreases in volume and cracks. Skinny does not give sufficient strength. Clay for the preparation of the solution are of different fatty or plasticity. There are clay deposits from which a solution of normal fatness is prepared without adding sand. Sometimes you have to mix two or three clays taken from different places, and strictly dosing them. First, they are mixed in dry form, then put it with water. If clays are fattened, then sand is added to them, the number of which can fluctuate 0.5 to 5 parts by volume. The most common ratio of clay and sand in the finished solution: 1: 1 or 1: 2. The amount of water is approximately 1/4 of the clay volume. Fat clays will require more sand, which should be fine-grained and do not contain foreign impurities. Sand is pre-sifted through a frequent sieve with cells in the light of 1.5x1.5 mm, not less than. Very skinny clays have to be reversed, removing the surplus sand from them.
1. Sleep the ball from the cooked solution and throw it about the floor. If the ball is crumbled, it means there is a lot of sand in the solution and little clay if cracks appeared in the resulting cake, it means that the sand is still a lot. If the ball did not give a single crack, the solution is normal or greasy.
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Method for checking the quality of clay 1. Determination of plasticity (fat) of the clay solution; but. small plasticity (skinny solution); b. Middle plasticity (normal), in. High plasticity (fat); 2. Determination of the plasticity of the clay solution by the "ball" method: a. a small plasticity solution ball (compression 1 / 5-1 / 4 diameter); b. a ball of a high-plate solution (compression 1/2 diameter); 3. Determination of the plasticity of the clay solution by the method of "burning" (left - stretching, on the right - bending around the roller) |
1. For the preparation of a solution, the clay is soaked for 2-3 days in a large wooden box, an inshance of tin, or in a special iron "trough." Then weave rubber boots and, gradually adding sand, it will turn it until it remains a single clay lump. You can smash clay lumps with a special tamper. Then the solution is torn and grind (or removed) the remaining clay pieces. A well-mixed solution, where sand and clay are in the desired proportion, must crawl from a steel shovel or a trowel, and not adhere to them. If you apply a smooth layer of solution (3-4 mm), put the second brick on top, pressing it (caught), and after five minutes try to raise the top, then with good quality the solution, the lower should not break away. If you lower the stick (cuttings of shovel, etc.), then the trail will remain insignificant. A very fat solution will leave a peculous film on a stick; Skinny - will not leave tracks at all.
2. When the clay is normal for fat, does not require the addition of sand, then they do. Make a boardwalk or shield with a size of 1.5x1.5 m, called a slaughter. Stirring clay on Earth is not recommended, as it will fall into it and various impurities. On the battlefields are poured with clay layers and wetted with water. As soon as the clay softening, it is twisted several times, it is crushed into a bunch in the form of a narrow bed with a height of 300-350 mm. The length of the bed depends on the amount of clay. Then, on this garden, strike a wooden shovel strikes, as if cut off from the garden, a slope for a plate switches. From the blows of lumps are broken, stunning. Round stones and extraneous impurities are removed during operation. Then the clay again moved, they are crushed into bed and crushed again, causing shovel blows. This operation is repeated 3-5 times until all lumps are broken.
If sand is added to the clay, then this is done. Sand bulk in the form of a wide bed, make in it recesses, pour clay with layers, wetted with water and fall asleep with sand, withstand the right time until the clay softening. Then it is repeatedly shuffled with sand, they collect in bed and crushed exactly as described above. Mine clay is needed as much time until it is completely mixed with sand and will not become homogeneous. In this case, clays in the solution should be so much so that it can only fill the gaps between the sands.
A well-shuffled clay solution with the desired amount of sand and water should crawl from steel shovel, but not spread over it. To the touch, it is a slippery mass, with a uniform filling of sand, without clay or sandy bunches. This clay solution has one drawback: large particles often remain in it, which do not allow thin seams and besides the traumatic hands. During operation, the clay solution has to prove all the time by hand, removing all sorts of foreign particles, and it makes it difficult and slows down. It is best to strain this solution through frequent sieve.
3. If the clay of normal fatness is used, which does not require the addition of sand, then it is covered in a box or barrel layers, wetted with water, and poured on top. Clay turns out a few hours. Then it is thoroughly stirred and filtered through a sieve with cells in the light of 3x3 mm. By adding water in the workplace, reach the necessary density of the solution.
When sand is added to the clay, then all components measure the necessary doses. Materials are individually sifted. After turning the clay, it is filled with it, sand is added, stirred and reload again.
Store clay solutions should be in a closed dish, so that foreign objects do not accidentally fall into the solution. The time spent on sieving materials or polling the solution pays off with more than in the oven masonry.
The clay solution makes the masonry durable, but provided that the masonry seam is not more than 5 millimeters. For experienced seam masters, 3 mm thick - the usual thing. Why fat seam does not promote strength brick masonry? Of the thick seam, the solution will quickly start sharpened, which will affect the quality of the furnace and additional fuel consumption. How can you get thin seams? First of all, you need to pay attention to the thoroughness of mixing the solution. Then the solution must be strain through the sieve. Cells in sieve should be no more than 3 mm. It is also important for the solution to choose the right sand. Grain size in the sand should not exceed 1 mm. In rare cases, sand with grain is more than 1 mm, but not larger than 1.5 mm.
The plasticity of the solution is also an important condition. The solution should not be either fat, nor skinny, but normal. Otherwise quality work Furnaces do not get.
The solution will be more durable if in each bucket of the solution is to add 100 g or 150 g of patterned salt. If the salt is large, it must be dissolved in water. Finnish cookies are taken into a solution for an oven to add Portland cement. On the bucket of the solution (10 liters) they put 0.5 liters or 1 liter of cement. It is necessary to spend this solution within an hour.
Clay for a solution can be of different plasticity and fatty. There is such a clay from which a solution without sand is prepared. Also, some live shops mix two or three grade clay from different places. If such a mixture of clay turns out to be fat, it is plugged with 0.5 to 5 parts of sand relative to the total volume. Sand sieves through fine sieve (1.5 mm).
An experienced master will determine the quality and fat content of clay with hand, to the touch. Inexperienced wizards can choose one of the ways to check:
1. A small amount of clay is taken (0.5 l) with the addition of water. The clay is warm up to obtain a steep dough. Then you need to roll the ball (the diameter of about 50 mm), from which to make a pellet (100 mm). Prepare the second ball. Ball and pellet dried 2 or 3 days. If clay is fat, cracks will appear on these products. Sand add to such clay. If clay is suitable for a solution, then the ball and the pellet will be without cracks and will not harm, falling from the meter height. Skinny clay when drying does not crack, but it does not have strength. In such a clay you need to add a fatal clay. Adding into a solution of sand or clay is carried out gradually, check the quality of the solution after each added portion.
2. For the second method of checking clay, a greater amount of clay is required - 2 or 3 liters, capacity and fun. Clay must be poured with water, smash lumps and mix the cheerful. Bold clay sticks to the cheerful very much. In such a clay for making a solution you will need to add sand. Normal clay will remain on the cheerful of individual clots. Skinny clay will cover the cheerful thin layer. It adds more fatty clay.
3. The third method of determining clay on quality is considered the most accurate. The clay is made according to the first way. The ball rolled with hands is placed on a smooth plate. The second one is pressing the ball to the bottom plank before the cracks appear on it. What happens to a ball of skinny clay? It will fall into pieces with even light juggles. Grease clay in the ball will give cracks with an increase in 1/2 diameter, and normal - at 1/3.
From the same clay, from which the ball is made, you need to roll thin flagellas (15 mm thick and 150 mm long). The flagella needs to be stretched or hugged a ring around a smooth stick (50 mm diameter). If the harness is scattered from oily clay, it is evenly pulled out and skews. With its flexion there are no cracks, and the breakdown of the break is sharp. Normal clay is pulled too smoothly. It breaks down with a decrease in the thickness of the harness by 15 or 20%. When flexing the harness is the formation of small cracks. Skinny clay is almost not stretched, it breaks unevenly, and many breaks and cracks appear on the bends.
Repeat this procedure with crushing the ball, stretching and flexing the flagellation follows several times before selecting normal clay or changing the proportions in its composition - either adding sand, or removing some of its part or completely.
There are I. various methods Preparation of the solution.
1. This method can be used with normal clay, in which you do not need to add sand. On the boarding shield (1.5 m x 1.5 m) layers clay. Then it must be moistened with water and after softening shock. From wet and mixed clay make the ridge with a height of 3 cm - 3.5 cm. The length of the ridge will be arbitrary depending on how much clay will be taken for the solution. Then the wooden shovel across the entire length of the ridges are caused by cutting strikes. The lumps from the blows are grinding and impel. Foreign pollution and stones are removed. This operation must be repeated to the complete disappearance of lumps.
If it is necessary to add sand into clap, this is done. The clay is placed on the sand layer, then wetted and fall asleep with the second layer of sand. After softening, the clay is broken with a shovel lump and repeatedly shuffle to a homogeneous mass. A qualitatively mixed solution, while observing the correct sand rate, slides, and does not spread from steel shovels. The solution should be slippery and without clay or sandy lumps. For a better quality, the solution should be strain using frequent sieve.
2. This method is the sequence of the following actions. If you do not need to add sand in the clay, then it is placed in the box and wet. Top completely poured with water. Leave it for several hours to turn it out. Then stirred and passed through a sieve (3 mm).
If you need to add sand, then all components are first sifted through a sieve separately. The clay is soaked separately, passes the stirred clay through the sieve, and only then sanding sand. Everything is again thoroughly mixed and filtered.
Filling a solution for oven laying is a very important and reappeared condition in the process.
The masonry on the clay solution is solid only in a dry place and thin seams - no more than 5 mm. Experienced Masters - Pechers lead a laying with a thickness of the seams of 3 mm. The solution from thick seams is quickly sharpened, air is assessed in them, which worsens the furnace operation and causes excessive fuel consumption. It is possible to obtain thin seams with a thickness of 3 mm only from a well-mixed solution, expanded through a sieve with 3 x 3 mm cells. Sand for the solution should be small, with grain size up to 1 mm, but sometimes used to 1.5 mm.
For furnace masonry, a large amount of solution is required - from 1/10 to 1/13 of the furnace volume, counting on the outside size, or up to 1/8 of the labeled brick, which corresponds to an average of 25 liters (2.5 buckets) per 100 pcs. Brick. In terms of its composition, the clay solution should not differ from the composition of the brick and tolerate the heating to 800 - 1000 ° C, without losing the strength and not highlighting harmful evaporation. From heating and cooling, the solution changes its volume equally with brick and therefore maintains a solid masonry without cracks in the seams. It should be remembered the golden relief rule - the smaller the clay in the oven laying, the higher its quality. This indicates the need to perform oven laying with thinner seams.
A brick clay is considered to be the best solution, that is, the one from which the brick is made, so many cookies prefer to apply a raw brick battle for the preparation of a solution. Masonry solution should be plastic, moderately fat, or, as they say, normal. The fatty solution, hidden, decreases in volume and cracks. Skinny does not give sufficient strength, poorly connects bricks among themselves and in the future it is easily sharpened from the seams, breaking the work of the furnace as a whole.
The strength of the clay solution increases slightly, if 100-150 g of the cooking salt add to one bucket. The fine salt is stirred with a solution, and large is pre-dissolved in water. In Finland, the cooking is added to a bucket of a solution from 0.5 to 1 l portland cement, mixing it in a dry form or pre-gated water. It is necessary to apply it to the case no later than an hour after cooking.
Clay for the preparation of the solution are of different fatty or plasticity. There are clay deposits from which a solution of normal fatness is prepared without adding sand. Sometimes you have to mix two - three clays taken from different places, and strictly dosing them. First, they are mixed in dry form, then put it with water. If clays are fattened, sand is added to them, the amount of which can vary from 0.5 to 5 parts by volume. Sands are pre-sifted through a frequent sieve with cells in the light of 1.5 x 1.5 mm, not less than. Very skinny clay have to be reversed, removing the surplus of sand from them.
Experienced Masters - Pechniki determine the quality of clay to the touch, and beginning cooks, we recommend using the most simplest ways to check.
The first way. Take 0.5 liters of clay, they add some water to it and carefully knead hands until it elevates the water completely and will not stick to the hands. Preparing a steep dough, roll the ball with a diameter of 40 - 50 mm and from the same ball make a pellet with a diameter of 100 mm. They drown them in normal conditions 2 - 3 days. If there are cracks on the ball or cake during this time, it means that the clay is fat and requires the addition of sand. If there are no cracks on the ball and cake after drying, and the ball, falling from a height of 1 m, does not scatter, it means that this clay is suitable for the preparation of the solution. Skinny clays are not cracking, but do not have strength, they need to add more fatty clays. Sand or clay is added for several techniques, checking the quality of the resulting solution every time. Figure 183, and shows a good and poor quality solution.
The second way. Take 2 - 3 liters of clays, placed in some kind of dishes, poured with water, melted lumps and stirred by cheerful. If clay sticks greatly to the cheerful (it is completely enveloped), it means that it is fat. In such a clay you need to add sand. If individual clots remain on the cheerfish, then such clay is considered normal, and the solution is prepared from the sand without adding sand. If the paddle is covered with a thin layer of clay, it means that it is skinny, and requires the addition of oily clay in certain quantities.
Third way. This is the most accurate way to determine the quality of clay necessary for the manufacture of bricks. 0.5 liters of clays knead the thickness of the steep dough and thoroughly knead the hands as indicated in the first method. From the cooked clay dough, the ball with a diameter of 40 - 50 mm is rolled with their hands, put it between two smooth (planed) powders and smoothly press on the top, gradually squeezing the ball. Compression is repeated while cracks are formed on the ball. In this case, the fat content of clay depends on the size of flattening the ball and the nature of the resulting cracks.
The ball made of skinny clay (Suglinka), with a slight nazhma, disintegrates into pieces. The ball of clay is a little fatal than the loam, with a compression on 1/5 - 1/4 of its diameter (Fig. 183.6) gives cracks. The ball from normal clay gives cracks when compressed by 1/3 diameter. The bulb from fatty clay gives thin cracks when compressing it on 1/2 diameter (Fig. 183, B).
From the same clay test, that both the ball roll over the flavors with a thickness of 10 - 15 mm, 150 - 200 mm long. The flagellas stretch (Fig. 183, d) or bend in the form of a ring around a round and smooth wooden rock with a diameter of 40 - 50 mm (Fig. 183, D, A, B, B). The flaky flayer is stretched smoothly, gradually soles, forming sharp ends at the place of break, and it does not form cracks when flexing. The firing of normal clay is drawn smoothly and breaks down when the thickness of it becomes less than the thickness of the burning of 15-20%, and small cracks are formed during bending. The flagellum of skinny clay is stretched little, gives an uneven gap, and when flexing, forms many cracks and breaks.
Two -, three-time repeated, testing of the ball, stretching and flexing the flabby of the flavor allows you to choose a normal clay suitable for the manufacture of bricks - raw or solutions for masonry furnaces.
When testing has to mix two - three clays, adding sand or, on the contrary, removing it. Only such a selection you can find the best proportions of those or other materials.
Prepare a solution can be prepared in various ways.
The first way. When the clay is normal for fat, does not require the addition of sand, then they do. Make a boardwalk or a shield of 1.5 x 1.5 m in size, called a brisk. Stirring clay on Earth is not recommended, as it will fall into it and various impurities. On the battlefields are poured with clay layers and wetted with water. As soon as the clay softening, it is twisted several times, it is crushed into a bunch in the form of a narrow bed with a height of 300 - 350 mm. The length of the bed depends on the amount of clay. Then, on this garden, strike a wooden shovel strikes, as if cut off from the garden, a slight plate of slight plates. From the blows of lumps are broken, stunning. Round stones and extraneous impurities are removed during operation. Then the clay again moved, they are crushed into bed and crushed again, causing shovel blows. This operation is repeated 3 - 5 times, until all lumps are broken.
If sand is added to the clay, then this is done. Sand bulk in the form of a wide bed, make in it recesses, pour clay with layers, wetted with water and fall asleep with sand, withstand the right time until the clay softening. Then it is repeatedly shuffled with sand, they collect in bed and crushed exactly as described above. Mine clay is needed as much time until it is completely mixed with sand and will not become homogeneous. In this case, clays in the solution should be so much so that it can only fill the gaps between the sands. A well-mixed solution with the desired amount of sand and water should crawl from steel shovel, but not spread through it. To the touch, it is a slippery mass, with a uniform filling of sand, without clay or sandy bunches. This solution has one drawback: large particles often remain in it, which do not allow thin seams and besides traumatic hands. During operation, the solution has to prove all the time with his hands, removing all sorts of foreign particles, and it makes it difficult and slows down. It is best to strain this solution through frequent sieve.
The second way. If the clay of normal fatness is used, which does not require the addition of sand, then it is covered in a box or barrel layers, wetted with water, and poured on top. Clay turns out a few hours. Then it is thoroughly stirred and filtered through a sieve with cells in the light 3 x 3 mm. By adding water in the workplace, reach the necessary density of the solution.
When sand is added to the clay, then all components measure the necessary doses. Materials are individually sifted. After turning the clay, it is filled with it, sand is added, stirred and reload again.
Store clay solutions should be in a closed dish, so that foreign objects do not accidentally fall into the solution. The time spent on sieving materials or polling the solution pays off with more than in the oven masonry.
