Useful Tips

Concrete casting

Choose a reference point. The first side of our foundation must be tied to some object of our site.

Example. Let's make our foundation (house) parallel to one of the sides of the fence. Therefore, we stretch the first twine equidistant from this side of the fence to the desired distance.

Building a right angle (90⁰). As an example, we will consider a rectangular foundation in which all angles are as close as possible to 90⁰.

There are several ways to do this. We will consider 2 main ones. © www.gvozdem.ru

Method 1. The Golden Triangle Rule

To construct a right angle, we will use the Pythagorean theorem.

Formula

In order not to delve into the geometry, let’s try to describe it more simply. To between two segments a and b To make an angle of 90⁰, you need to add the lengths of these segments and derive the root from this sum. The resulting number will be the length of our diagonal connecting our segments. It is very simple to make a calculation using a calculator.

Usually, when marking the foundation, the dimensions of the sides are taken, so that when removing from the root, an integer is obtained. Example: 3x4x4, 6x108.

If you have a roulette, then in general there will be no problems if you take segments other than those commonly used. For example: 3х3х4,24, 2х2х2,83, 4х6х7,21

If we took measurements in meters, then the values ​​are very clear: 4m24cm, 2m83cm, 7m21cm.

Calculator

It is also worth noting that measurements can be made in any length measurement systems. The main thing is to use the aspect ratio known to us: 3x4x4 meter, 3x4x4 cm, etc. That is, even if you don’t have a tool for measuring length, you can take, for example, a rail (the length of the rail does not matter) and measure it (3 rails x 4 rails x 5 rails).

Now let's see how to put it into practice.

Method 1. The rules of the golden triangle (T. Pythagoras)

Consider, for example, the construction of a rectangular foundation with dimensions of 6x8m using a golden triangle (T. Pythagoras).

1. Mark the first side of the foundation. This is the easiest part to build our rectangle. The main thing to remember. If we want our foundation (house) to be parallel to one of the sides of the fence or another object on the site or beyond, then we make the first line of our foundation equidistant from the object we have chosen. We described this procedure above. To accommodate the first twine you can use pegs firmly fixed in the ground, but ideally for this purpose use a castor. We will use it. The distance between the castoffs for this side will be 14m: between the castoffs and future corners of 3m and 8m under the foundation.

2. Pull the second string as perpendicularly as possible to the first. Ideally perpendicular to practice, it is difficult to pull, so in the figure we also displayed it not much deflected.

3. Fasten both cords at the intersection. You can fasten it with a bracket or tape. The main thing is to be reliable.

4. We proceed to the formation of a right angle using the Pythagorean theorem. We will build a right triangle with legs 3 by 4 meters and a hypotenuse of 5 meters. To begin with, measure 4 meters on the first twine from the intersection of twine, and on the second 3 meters. We put marks on the lace using tape (clothespin, etc.).

5. We connect both marks with a tape measure. We fix one end of the roulette at the mark of 4 meters and lead towards the mark of 3 meters on the other twine.

6. If we have a right triangle, then both marks should converge at a distance of 5 meters. In our case, the marks did not agree. Therefore, we move the twine in our case to the right until the moment when the 3 m mark coincides with the division of the roulette by 5 m.

7. As a result, we have a right-angled triangle with an angle of 90 ° between two cords.

8. We do not need more marks and can be removed.

9. We proceed to the construction of the rectangle. On both cords we measure the lengths of the sides of our foundation 6 and 8 meters, respectively. Put marks on the twine.

10. Pull the third twine as perpendicularly as possible to the first twine. We fasten both cords at the level of 8 m.

11. Pull the fourth twine as perpendicularly as possible to the second twine. We fasten both cords to 6 meters.

12. Make marks on the third twine 6 meters and on the fourth 8 meters.

13. To get a quadrilateral with right angles in our case, it is necessary that both marks on the third and fourth twine coincide. To do this, move both cords up to the point of connecting the marks.

14. As a result, if everything was correctly measured, then we should get the right rectangle. Let's check if it turned out by measuring the diagonals.


15. Measure the lengths of the diagonals. If they are the same, as in our case, we have a regular rectangle. Diagonals have the same length in an isosceles trapezoid. But we know one angle of 90 °, but there are no such angles in an isosceles trapezoid.

16. Ready markup of a rectangular foundation using the Pythagorean theorem. © www.gvozdem.ru

Method 2. Web

A very simple way to make a markup in the form of a rectangle with angles of 90 °. The most important thing that we need is a twine, which does not stretch, and the accuracy of your measurements with a tape measure.

1. Cut the pieces of twine that we need to form the markup. In this example, we are building a foundation with sides of 6 by 8 meters. Also, for the correct construction of the rectangle, we will need equal diagonals, which for the 6 by 8 meter rectangle will be 10 meters (the Pythagorean described above). You also need to take a stock of the length of the twine on the mount.

2. Connect our "web" as in the picture. We fasten the sides with diagonals in 4 places in the corners. It is not necessary to fasten the diagonals themselves at the intersection point.

3. Pull the first twine (points 1,2). We will mount it with the help of pegs. The main thing is that the pegs are held firmly in the ground and when pulled by our structure they are not taken away. This important point must be taken into account.

4. Tighten the angle 3. The main condition is that the twine 1-3 and the diagonal 2-3 do not sag and are as tight as possible. After fixing with a peg at point 3, we have an angle at point 1 at 90 1.

5. Pull the angle 4 and set the peg. We make sure that the twine at points 2-4, 3-4 and the diagonal 1-4 do not sag and are as tight as possible.

6. If all conditions are met, then as a result we should get a rectangle with angles as close as possible 90⁰.

Marking under the column foundation

We make a two-tier castoff. The lower tier is the pillar level.

The upper tier of the castoff is the level of grillage.

Laying under the slab foundation

The easiest way to markup. We build a rectangle according to the size of the foundation using the Pythagorean theorem to find a right angle. © www.gvozdem.ru

In this article, we examined how to make markings for the foundation with our own hands with the construction of a rectangle with angles of 90 °. In general, there is nothing difficult in the markup. The price of the question is the cost of twine, boards for casting (economy option - pegs) and the ability to use roulette.

Cast concrete

Cast concrete was developed and introduced into the construction industry at the end of the 20th century.

Its main purpose is the finishing of horizontal surfaces. With its use, concrete casting ceased to require labor-intensive vibration compaction, and high quality surfaces became available to the master of initial qualification without complicated and bulky tools.

The purpose of concrete molds

Mankind first heard about cast concrete at the end of the 20th century. The main purpose of the elastic material is to finish the horizontal surfaces. Due to the ability of the mortar to spread and level, the construction process was greatly simplified; concrete casting ceased to require vibration compaction. Such material willingly takes the form of a matrix, quickly solidifies. Other advantages of cast concrete include:

  • plasticity and simplicity of filling,
  • the ability to adjust the surface, which is achieved by adding substances that retain moisture,
  • resistance to penetration of water,
  • long contact with earth and liquids,
  • insensitive to temperature extremes.
  • In addition, the ebb tide procedure does not require special skills and the use of bulky tools from the master.

    Molds for concrete products, which experts call matrices, are containers of various sizes with an open top, where the finished cement mortar is poured. So that the product does not deform and is easily removed after drying, polymers (crushed stone or expanded clay) are added to the substance. Colored designs are obtained by adding dyes to the solution. If the mold is deep, then a rule or a vibration seal is used to seal the material.

    Differences of cast concrete from ordinary

    Cast concrete differs from ordinary in the presence of, in addition to water, cement and sand, polymer plasticizers, providing properties such as

    • Elasticity.
    • The ability to spread over the surface.
    • Ability to level the surface.
    • Low shrinkage.

    For the casting of such concrete, bulky equipment is not required, the composition can be prepared in a conventional construction bath with a drill - mixer.

    Varieties of injection molds

    Ready-made matrices are made of plastic, wood, metal, polyurethane, fiberglass. Among the wide variety of concrete casting molds, models designed for:

  • manufacturing of paving slabs (pavers, garden paths, massive slabs),
  • creating borders and gutters,
  • the ebb of the facing-facade tile, which looks like chipped natural stone,
  • the manufacture of fences, poles, unilateral and bilateral fences, inserts,
  • creating elements of landscape gardening architecture (vases, street urns, benches, planters, fountains, peaks, balusters, lampposts, sculptures, balustrades, etc.).
  • Many homeowners who want to save money on buying concrete pouring molds do it themselves from improvised materials. Wooden and metal molds are made so that it is possible to separate the parts and remove the finished product. From the silicone matrices, the concrete figure can be obtained without much effort.

    Advantages and disadvantages of cast concrete

    The main advantage of cast concrete is its ductility. Thanks to this, its filling is facilitated and there is no need to resort to vibration compaction, as required by the pouring of ordinary concrete.

    The main characteristics of plasticity

    The composition of cast concrete also includes additives that retain moisture in the material. This increases the time available for surface adjustment and increases the flowability of the composition.

    Cast concrete is also resistant to moisture, can be in contact with the ground for a long time and withstands contact with water. Polymer additives make the material insensitive to temperature extremes.

    Plasticity of cast concrete

    The main and perhaps the only drawback of cast concrete is its high cost due to the high price of polymer additives, up to one twentieth of the total volume.

    DIY matrix making

    If you have the necessary tools, you can make molds for the production of concrete products with your own hands. This will allow you to get an original matrix for the manufacture of paving slabs and garden sculptures.

    Most often, wood and polystyrene are used as the starting material. Often folk craftsmen use carriages for food as molds.

    DIY ideas for making matrices, the subtleties of manufacturing and the scope of application:

  • To make a mold from wood or an oriented chipboard, you will need a tape measure, a saw, an ax, a corner, a level, a screwdriver and steel corners for a screed. Cut blanks are interconnected by self-tapping screws, which can easily be unscrewed if it is necessary to extract a concrete product. The finished form is suitable for ebb curbs, gutters, household fences, piles. Before use, the wooden casting is thoroughly moistened with water so that the concrete product easily moves away from the matrix walls.
  • Metal matrices require a bench tool. In the manufacture of molds for concrete, you will need metal scissors, a workbench, a vice, a grinder, a mallet and a small corner to create bends. This design can be made collapsible, which greatly simplifies the process of extracting the finished concrete product from the matrix. Before pouring a sand-cement mortar, the mold is carefully lubricated with machine oil.
  • Polyurethane or silicone matrix is ​​made of various plasticizers. To create it, you need a stable casting table, a template by which a form will be created, a container for mixing the mortar, a special construction drill or a solid stick for kneading the composition. In addition, a scalpel or knife is useful, which will help trim the finished parts. After mixing the plasticizers, the mixture is poured into models placed face up. The solution should be administered slowly, in a fine stream, so that no bubbles form. Ready-made elastic molds are suitable for the outflow of artificial stone, pavers, small garden sculptures.
  • Besides, many specialists resort to creating molds for casting concrete foam products. From it you can create structures that differ in size and configuration. The only drawback of such models is that they will have to be destroyed after the composition hardens. Among the unusual solutions can also include the use of baby molds for sand, buckets, old kitchen utensils, tires (if you need to get a rounded figure). Some masters even resort to the ebb of matrices in the ground, although the clarity of the lines in such products should be forgotten.

    The variety of ready-made forms for pouring concrete allows you to create unusual architectural structures, original sculptures for landscape design, a solid road and pavement, reliable peaks, fences and other structures.

    Given the high cost of store matrices, each master will be able to make an injection mold with his own hands, using ready-made ideas, connecting his own imagination and armed with the necessary tool.

    Molds for concrete

    A mold for concrete (or matrix) is a container open from above, corresponding in size and configuration to the molded product. A cement mortar is poured into it with the addition (if necessary) of polymer plasticizers, dyes and other additives, for example, crushed stone of fine fractions or expanded clay. If necessary, the concrete surface is compacted with a rule or a vibration damper. After the product has hardened, it is removed from the matrix or the matrix is ​​removed from the product

    They are made from a wide variety of materials, sometimes just from improvised

    Plastic molds for domestic use

    At home, plastic molds are often used for concrete casting. Silicone molds are also popular, they are more often used for casting landscape design elements.

    Mold Making Tools

    Tools for making a matrix depend on its type.

    To produce molds from wood or OSB, you will need a set of carpentry tools:

    • roulette,
    • saw,
    • ax,
    • corner
    • level,
    • screwdriver
    • steel corners or tape ties.

    Carpentry Tool Set

    To make metal, you need a set of bench tools

    • Workbench with a vise.
    • Scissors for metal.
    • Bulgarian.
    • A mallet and a 50 × 50 long corner for folds.

    Workbench with a vice and other metalwork tools

    For a silicone or polyurethane matrix,

    • filling table
    • stable and leveling casting table in two planes,

    • flat filling tanks
    • containers for mixing the composition with plasticizer and pouring,
    • agitator drill or manual agitator,
    • scalpel and knife for fine-tuning details.

    The main types of forms

    By type of casting concrete are divided into:

    Rigid matrices are made of wood, metal, chipboard, sheet plastic.

    Rigid mold for concrete casting from wood

    Paving slabs are cast in them,

    Flexible forms are most often cast from plastic or silicone. They are used for casting artificial stone.

    The advantage of silicone is its strength and durability. Silicone matrices are expensive, but they last a long time. Moreover, casting does not stick to them even without any lubrication.

    According to their purpose, the matrices differ in:

    • For casting tiles.
    • For casting decorative stones.
    • For casting curly products.

    Forms are also divided into collapsible and non-collapsible. Non-separable are used for casting a single product and destroyed to remove it.

    Collapsible mold for concrete casting

    Collapsible dies for casting are recyclable. Depending on the strength and wear resistance of the material, several copies are cast to several hundred products.

    Making molds at home

    If you decide to make an artificial stone with your own hands, the die for casting can be cut from foam. Do not forget to strengthen it, for example, wrapping it in several layers with tape.

    Форму также можно самостоятельно отлить из полиуретана или силикона. Для этого придется приобрести готовые смеси и пластификаторы, самостоятельно в домашних условиях их не приготовить.

    The first step in creating a matrix is ​​to make a model. The model accurately repeats the dimensions and shape of the finished product. As a model, you can use an already cast sample, you can also cut the model out of wood, sculpt it from plaster or wax.

    Filling containers should be the size of a model (or group of models, if the shape is planned multi-seat) plus the thickness of the matrix. Place the model (or models) face up in the filling tank, making sure that the distance to the walls from the model is constant. After that, in a separate container (a bucket with a small spout is best), pour the mixture into a plasticizer and mix thoroughly. Models need to be poured slowly, with a uniform thin stream, providing complete wetting of the models and walls of the filling containers and avoiding the formation of air bubbles.

    After polymerization of the mixture, it remains to extract the models - the matrices are ready for concrete casting.

    The method of casting concrete for the manufacture of concrete products

    Casting concrete products into matrices in single pieces or in small runs does not require complicated equipment. In this case, you can do with manual kneading and manual sealing of the solution.

    If you plan to cast concrete into molds with an average circulation, it is better to get a concrete mixer and a vibro-compactor.

    Making concrete castings at home is a simple process. However, the master should pay attention to a number of subtleties.

    If it is necessary to cast large products, such as curbs, columns or piles, the formwork is best made of wood or OSB. When casting products with a side of more than half a meter in size, additional stiffening elements will be required so that the formwork does not open during pouring. The formwork should be made collapsible, before pouring the solution it should be very well soaked. This will make it easy to remove the formwork after the casting has hardened, eliminating the adherence of concrete to the mold. A mold made of OSB, plywood or metal for the same purpose is lubricated with machine oil.

    If the tree is not available, then, in extreme cases, the die can be dug in the ground. Sand should be poured into the excavated hole, moisten it well and pour the solution. Of course, dimensional accuracy and surface quality in case of casting into the ground will be more than modest.

    Scope of concrete casting

    Cast concrete is used in conditions where the pouring of ordinary concrete is impossible or very difficult. For example, if vibration compaction is labor intensive or difficult due to configuration

    Cast concrete is also widely used in production.

    • land reclamation
    • prefabricated reinforced concrete structures,
    • stairs
    • underfloor heating and base for flooring.

    Another wide area of ​​application is landscape design and suburban construction, including tile casting.

    Artificial stone is also made of cast concrete.

    Simple technology and affordable equipment make it possible to cast decorative materials and small architectural products with your own hands.

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    Modern analogues

    Now the market offers a wide range for every taste.

    The use of modern materials, from which molds are made for pouring concrete, give a real opportunity to manufacture products with almost perfect accuracy of transfer of the surface of the texture.

    If we talk about forms for concrete, which are used in the modern production process, they can be rigid and flexible. In most cases, plastic is used as the material for their manufacture.

    The material from which the mold for concrete will be made must be alkaline and impact resistant.

    Only with these characteristics, tiles, artificial stone, furniture and other products made of concrete will be of the highest quality. It is not necessary to buy molds for concrete at all, you can easily make them yourself.

    Manufacturing tools

    For independent creation of various products (tiles, decorative stone, etc.), the following materials and tools will be needed:

    Many prefer this form, since it is used immediately when laying a track, and the result looks no less impressive than when laying a track from individual tiles.

    1. Portland cement,
    2. Sand (river, quarry, building or any other),
    3. Construction grid in increments of 50-60 mm,
    4. Wide tape or any tape other than paper tape
    5. Nippers or scissors for metal,
    6. Trowel (preferably iron, not plastic),
    7. Thick garbage bag,
    8. Capacity for the preparation of mortar,
    9. Brush
    10. Pigments for coloring concrete (optional),
    11. Polymer paint for stone or concrete (optional).

    There are several varieties for concrete. With the help of some, tiles are made, with the help of others - various decorative stones, and still others are used for casting curly products.

    This form allows you to make a neat track in a matter of hours.

    Plastic is an excellent material for the manufacture of concrete, due to its unique technical properties. Along with this, if the type of product does not need to use molds from plastic, you can opt for another material for making yourself.

    Making concrete molds with your own hands is typical for the production of special fiberglass blanks, with which you can produce complex architectural figures and concrete products (sculptures, balusters, flowerpots, vases), polymer concrete products, as well as concrete products with immediate stripping (for monuments and fences).

    If we talk about small-piece products, then the most common types for their production are paving slabs, paving stones and facade stones. The forms with which tiles, facade stone and other products of this plan are made are quite durable and can be successfully used in more than 300 cycles. Along with this, such more expensive on sale than flexible options that can be made by yourself using the vacuum molding method.

    Vacuum molding is a universal production method with which you can set up fast production of concrete molds. This method makes it possible to produce molds for concrete of any surface texture and any size. As a material for the manufacture, a wide variety of plastics can be used, including polystyrene, ABS, PVC, PET, etc. The durability of the manufactured blanks will depend on the type of plastic used, its thickness and properties. For example, molds made of ABS plastic can withstand more than 300 concrete pouring cycles, while PET is markedly less durable. In addition, the geometry of the product also affects this parameter.

    Create Instructions

    The option of "under the paving stones" is in greatest demand.

    If you need to create large castings (curbs, borders, piles), the formwork is best made of wood. If possible, the form should be made collapsible, plus the tree must be well wetted before pouring. The method is good if there is a need to manufacture a relatively large number of similar products with a clear geometry (stone, tile, etc.).

    If you do not have the opportunity to use a tree, a shape in the form of a rectangle or a cube can be made directly in the ground, simply pulling out a hole of suitable size. Sand should be poured into the pits, pour water on top to “lubricate” and moisturize, after which they can be poured with concrete and covered from above. After the concrete has hardened, the molds can be used for their intended purpose.

    To create stencils with which tiles or stone will be made, you can use any material (silicone, wood, plastic, polystyrene, polyurethane, rubber). It all depends on the capabilities and imagination of the builder. Some experts have learned to adapt even old dishes or baby molds for work, which we will discuss separately. The main thing is that the container is suitable in size.

    If it is necessary to make a single printing casting, it can be made of foam. To do this, cut the necessary workpiece from the material, the field of which fill it with concrete. Polyfoam is a widely available material, so preliminary tests can be performed by creating a stencil for small cubes. The only drawback of the foam is the need for its destruction to extract concrete. But the possibility of obtaining castings of any configuration, even with a three-dimensional pattern, is an undoubted advantage.

    If you need to make a concrete ring, you can use old bicycle or concrete tires as a stencil. For this, even tires from strollers and scooters can be adapted. If nothing suitable is available, simply dig a circle in the ground, then put a bucket in its center and use the form you received as intended.

    Custom ideas

    If after studying the offer you did not find the desired option, then you can try to do it yourself.

    Making curly concrete products is not so simple. This is a very time-consuming process that requires a lot of effort and time. Buying a ready-made one is, of course, easier, but if you want to get something unusual, then you will have to use imagination and improvised tools to make a stencil with your own hands. Ideas for creating original forms with their own hands surround us everywhere, just most people do not notice them and immediately go to the store for ready-made options, which is not entirely correct.

    Currently, many food products (convenience foods, confectionery, fruits, etc.) are sold in plastic containers. They are great as forms for creating paving slabs.

    Another great idea is the transparent and colored plastic granules that are used to make bottles. They need to add a solution in different proportions. The result is a diverse and interesting tile from which you can lay out beautiful and original mosaics on the sidewalks.

    Cliches can be made of laminated particleboard. Sometimes you don’t even have to buy it. Go to the sawing company. Surely the scraps that are waste to them will be given to you for free. With this option, paving slabs can be made rectangular, square, triangular.

    If you decide to do it yourself, you can be sure that your tile will be exclusive.

    For example, to create a rectangular stencil, you need to collect the semblance of a small box. To do this, cut out 5 rectangles, 4 of which should be the same size, and the fifth one so that it fits in size. Assemble parts with furniture screws or other fasteners. Confirmats are convenient in that they allow you to safely collect and disassemble the workpiece many times. Next, you need to wrap the resulting box with stretch film. So the tile is much faster to get out, in addition it will prevent sticking.

    The forms with which tiles, decorative stones and other similar products will be made should be soft to the touch, the material should look like silicone. It is not recommended to use very unusual stencils. Of course, the design of the track will turn out to be very original, but it will be quite difficult for the beginning master to lay out such a tile. Just pick it with even edges, at least for the first time, while you fill your hand. Spreading such a tile is a pleasure, and garbage will not fill up at the joints, so vengeance like a sidewalk is also very simple.

    Many even use molds for playing in the sandbox to make various concrete structures. For example, they are suitable for creating some kind of drawing on the sidewalk. In this case, the main canvas is laid out with tiles with smooth edges, and the sides, for example, can be trimmed with original figured products.

    If you want to save money during the repair work, do not rush to buy everything ready-made. Molds for making original and beautiful architectural concrete products can be easily made with your own hands!