Molds for concrete: plastic, wood, metal

The best option for making concrete products is a concrete mold. Its creation at home requires accurate calculations, knowledge of the characteristics of the material used and the future sample, and control of the production process. The matrices are strong and stable, easy to use, designed for repeated use, and no additional construction equipment is needed during production.

For small-scale construction work, according to industry experts, self-production of concrete molds is very profitable, since savings reach 70%.

When are they needed?

Molds for concrete products are indispensable in the manufacture of construction and decorative products by casting. The smaller and more refined the parts, the higher the quality requirements for the matrices. With their help, various construction samples and products for concrete decorations are produced:

Adaptations are necessary for those who make paving slabs.

blocks for construction;
fencing;
paving slabs;
reinforced concrete slabs;
architectural accessories;
blocks or rings for fireplaces;
drainage trays;
monolithic or hollow products.

Advantages, disadvantages

The formwork consists of several foam blocks connected into a single structure. Advantages of foam blocks for foundations:

The material combines two properties: sound insulation and heat insulation.
The blocks have a prefabricated base, installation is carried out 2 times faster than a conventional base.
Convenience when laying communications (sewage, water supply).
Due to the small weight of the products, transportation can be carried out without hiring special equipment.
The permissible air temperature at which foundation construction is allowed is 5°C.
Walls insulated with foam plastic are not susceptible to fungal destruction.
Does not produce “cold bridges”.
Eco-friendly.
The material has a smooth surface, and costs for finishing work are reduced.

But you should not consider permanent formwork a salvation from all troubles, despite so many positive aspects, it also has disadvantages.

Flaws:

Flammable material.
Installation with hiring specialists is very expensive.
The material has poor breathability, causing increased humidity indoors.

Knowing the listed qualities of the material, making formwork for pouring the foundation will not be difficult. All you need is the material and a little skill.

What are they made from?

The variety of concrete products requires suitable raw materials in order to produce appropriate molds for concrete products depending on the specifics of their use. Materials are selected according to technical parameters, processing methods, quality characteristics, and price category of the finished product.

Elastomers

Silicone stencils are convenient to use when you need to make something voluminous.
Elastomeric forms are used in the manufacture of complex volumetric structures that require precise geometric calculations, samples with small details, and high-precision bas-reliefs. It is difficult to make such a form at home, since it requires specialized cooking and crushing equipment. In addition, due to the intricacies of working with substances, consultation with a specialist is required before starting work. Inexpensive silicone stamps from China are popular for casting concrete under artificial stone. The following components are used in the manufacture of elastomeric matrices:

synthetic rubber;
formoplast;
compounds made of polyurethane or silicone.

Plastic

If the slab does not need to be calculated too accurately, then this type of stencil is suitable for it.
The production of large blocks and slabs that do not require precise calculations is carried out using plastic matrices. The main method for producing plastic molds is vacuum molding. The materials from which they are made are shown in the table:

Types of plastic	Peculiarities
Fiberglass	Possible cracks in the product due to poor adhesion to the cement matrix
Hard	Used for casting paving slabs, curbs, paving stones
Hard	Tendency to warp
ABS sheet	Suitable for making small products
	Tendency to delamination
	The need to use silicone lubricant
Film or sheet polystyrene	Fragile
Film or sheet polystyrene	Good reproduction of the texture of the samples
PVC plastic	High strength
PVC plastic	Does not require lubrication or cleaning due to weak adhesion

It is not often that you see fiberglass matrices used in the manufacture of products.
Fiberglass molds and ABS plastic dies are used less frequently when molding concrete products. Professional builders recommend that when making concrete blocks using plastic, make sure that there is rigid formwork. Thanks to it, the sample will acquire the desired relief, can be easily removed from the mold and will not disintegrate during the drying period.

Specifications

Due to the technical characteristics and unusual properties of the material, permanent formwork for foundations is popular in the construction of houses:

The weight of one cubic meter is 27-30 kg.
Frost resistance is designed for 300-600 cycles.
The material absorbs moisture poorly - 0.032 mg/(m*h*PA).
Polystyrene foam has good soundproofing properties - 49-53 dB.
The thermal conductivity of the structure is – 0.036 W/(mC).

Fixed blocks determine the size of the future structure. Models of end and wall blocks have the following parameters - 125x25x25, corner blocks - 70x25x25. The weight of one block is 1 kg. If we take into account the wall thickness of the polystyrene foam block - 5 cm, the concrete foundation will be equal to 15 cm.

How to make it yourself?

Molds for casting concrete are made using improvised means. So, you can make a foam stamp, and then fill it with a solution of cement and sand. Figured paving slabs are simply made at home using formwork assembled from pieces of laminate, chipboard, plywood, sawn into pieces of the required parameters and connected with screws. The cube tiles for the garden path are stamped using plastic food containers. To decorate or disguise errors with cast figures, skilled craftsmen use children's sand molds. Do-it-yourself concrete blocks are made using self-made formworks made of wood or metal.

Matrices for making blocks should not have a bottom.

Wooden

The matrix is assembled from several wooden boards.
The collapsible wooden form is constructed from 4 scraps of strong boards, about 35-50 mm thick. The dimensions of the product depend on the planned volumes of the block. Laying in small blocks is convenient, while laying in large blocks is faster. Connections in the product are made with coupling screws. To make a handle, a wire rod with a cross-section of 10 mm is suitable, the ends of which are flattened for drilling holes.

Metal

The drawing of homemade metal forms is identical to the drawing for constructing wooden formworks. To produce one block, 4 rectangular iron plates with a thickness of 3-4 mm are required. Other sizes depend on the size of the form itself. Grooves for fastenings are cut out on the sides of the metal sheets, and handles are welded to the ends. To delimit future blocks in the form, additional metal plates are required.

Products can be made from several metal plates.

What are the tracks for?

Garden paths perform two important functions:

Improve landscape design, give the garden a well-groomed appearance;
After precipitation, it will be possible to cross the site along the paths, get to the gazebo, etc. The paths are easy to clear of snow. So improved trafficability, zoning, emphasizing the boundaries of flower beds - these are the functional tasks of the paths.

How to use?

Prepared forms for pouring concrete are placed under a cover on a surface covered with fabric or film. For easy removal of the finished sample, the entire formwork is lubricated with machine oil. Then a solution is prepared for pouring future concrete products into molds. The matrices are filled with a mixture of sand, gravel and lime in a ratio of 1:4 to cement. It is important to choose the right amount of water so that the mixture is not too thick or runny. It is better to pour water in cool conditions so that it does not quickly evaporate, causing cracks to appear in the future product. Concrete is poured into molds to the top, after which the surface is leveled until smooth with a handy tool. The mixture sets and reaches its highest strength after 4 weeks.

Foundation Features

Formwork for a polystyrene foam foundation is a prefabricated permanent structure consisting of hollow blocks and foam slabs. Wall thickness - 40-150 mm. Length - 1.2 meters. For turns, separate corner elements are provided, the length of which is equal to a single block - 1 meter. Partitions are installed between the polystyrene foam walls, which are responsible for the width of the poured concrete. The indicator is not constant. Dimensions - 15,20, 25, 40 cm.

Fixed polystyrene foam formwork

Foundation pouring technology is used:

To make a warehouse or industrial space warm.
For insulation of pool walls.
To create a warm basement, equipment for gyms, recreation rooms.
During the construction of residential premises.

Expanded polystyrene

Expanded polystyrene - gas-filled material made from polystyrene is called polystyrene foam.

The function of the material is to insulate cold walls. Expanded polystyrene is used as block products to create a warm foundation.

Advantages

The advantage of foam construction is the speed of installation. According to experts, the method speeds up installation by 30%.

Advantages:

Despite the lightness of polystyrene foam, the foundation is strong enough to withstand the static and dynamic loads exerted by pouring concrete.
No insulation of the building facade is required.
It has a soft structure, laying communications is twice as simple.

Foam plastic tolerates chemicals well. The material practically does not absorb moisture and does not rot. Assembling formwork from foam blocks is reminiscent of Lego.

Flaws

In the process of using polystyrene foam, the thermal insulation and waterproofing properties are reduced. After 15-20 years, the home owner will have to replace the insulation and create an additional thermal insulation and waterproofing layer to reduce losses.
If you use only polystyrene lintels to reinforce the structure, the solution will soon disappoint; after a few years, the partition will collapse. To solve the problem, professionals use additional transverse reinforcement with metal rods.
Concrete requires uniform placement with periodic subsidence of the solution using auxiliary means. The speed of concrete pouring increases.
Assembling the overall foundation structure using polystyrene foam will be expensive.
The lower part of the foundation is poorly protected and has poor thermal insulation properties.
Plinth cladding required.

Requirements for organizing a workshop

To organize your own workshop for the production of decorative stone tiles, you must provide for the installation of the following types of equipment :

The room must have overhead crane beams, hoists and other lifting equipment.
The ceiling height must be at least 4.2 - 5.4 m to the bottom of the nearest protruding building structure.
The workshop must be provided with effective supply and exhaust ventilation with mechanical drive.
To reduce production costs, it is recommended to install a recycling system.
Each power equipment that requires connection to a 3-phase network must have its own circuit breaker with a calculated current strength.
The dosage of ingredients should be done using electronic scales to avoid mixing errors.
Mixing of the composition should take place using electric mixers, eliminating the heterogeneity of the mixture.
After forming, the concrete must be compacted on a vibrating table with high-frequency vibration function.
The steaming chamber should ensure a reduction in the hardening time of concrete products to minimum values, which allows for maximum savings on manufacturing costs.
It is recommended to install all machines with a numerical control (CNC) function, and organize automatic transport carts between stations to achieve complete automation of the process.
If a batching plant is available, it is recommended to install a separate heating system for inert components to obtain concrete without defects and damage to quality.

When installing a batching plant, the future business owner should study the technological capabilities of the equipment in advance, since it can significantly increase profitability through the sale of ready-mixed concrete, provided that they have their own or leasing vehicle mixers for its transportation.

Is certification required?

Mandatory certification of such tiles is required to be able to participate in tenders for the supply of products when it is necessary to cladding the facades of permanent apartment buildings.

The official document takes into account a number of important parameters:

Strength characteristics of products.
Consistency of the chemical composition and formulation of products.
Compliance of technical conditions developed by production enterprises with the requirements of current state regulations.
Providing the necessary physical and mechanical characteristics.
Reducing the number of defects in a batch of products.
No significant deviations from geometric dimensions, since GOST regulates these errors and reduces them to a minimum, obliging manufacturers to comply with the requirements.

Even if the manufacturer does not plan to enter the large-scale capital construction market, the presence of a certificate of conformity significantly increases the authority of the product in the eyes of the consumer, which also makes it possible to set a higher retail price for the product.

Calculation of cement mortar

The composition of architectural concrete is no different from the usual one used in construction and repair work. But for the production of archstone, they choose white or light gray Portland cement of good quality - usually grade M-500 or DO-400. The use of gray cement is undesirable, since the color of the product will eventually turn out faded.

There should be no lumps or foreign impurities, so before starting work it must be sifted (like sand). Mixing proportions directly depend on the brand of cement.

For the M-500 brand you will need the following composition:

Basic material – 1 part
Quartz sand – 3 parts
Water – 3 parts

To understand whether the solution is ready for use, you need to squeeze the composition tightly in your hand for 2-3 seconds, then release it and draw conclusions: if water is released, you need to add sand, but if the lump disintegrates, you can add a little water.

Below is a table with proportions:

Literature

A short dictionary of aesthetics
Nekrasova N.A., Nekrasov S.I., Sadikova O.G.
Thematic philosophical dictionary: Textbook - M.: MSU PS (MIIT), 2008. - 164 p.
Federal Law 169-FZ. About architectural activities in the Russian Federation
Schild E.
Construction physics - M.: Stroyizdat, 1982
Korchagina O. A.
Concrete and mortars - Tambov: TSTU Publishing House, 2004
Levit S. Ya.
Encyclopedia “Culturology of the XX century” - St. Petersburg University book, LLC “Aletheia”, 1998
Bazhenov Yu. M.
Concrete technology - 3rd ed. - M.: Publishing house ASV, 2003 - 500 p.
Novikov I.V.
Stone and concrete works - M.: Veche, 2006
Ivanova I.N.
Drawing and modeling - M.: publishing house, 2011
Sokolov V.N.
Modeling a figure - M.: Publishing House of the USSR Academy of Arts, 1962
Hessenberg K.
Sculpting Basics – Quarto Publishing plc., 2005

Professional additives for sculptured concrete

If you search on the Internet, you can find many offers for the sale of both imported and domestic additives to concrete mixtures. All of them, to one degree or another, contain the previously listed components. There are substitutes for construction quartz sand to lighten the weight of the mixture (marble or dolomite flour). In higher quality and more expensive mixtures, starch ether is added. It allows you to further reduce the sliding of the solution from vertical surfaces. For the same purpose, polypropylene fiber is added to the mixture in small quantities.

It can also be noted that in the literature, instead of the name RPP, the names of various latexes are often given (usually acrylic latex). In addition to SSS, latexes are used in many other industries, including the production of paints. Which paints to choose and how best to paint concrete is a topic for a separate article. Good luck to everyone in your work and see you again on .

Reviews

This year my husband and I got married and decided to buy a home. There wasn't enough money to buy a new one. We settled on building a house, but the option is also not a cheap one. To reduce costs, we used polystyrene foam formwork. We managed to spend less money and were able to build a house faster.

Olya. Krasnodar.

Our company is engaged in the construction of houses. Pouring a concrete base using foam blocks significantly reduces the time for building construction.

Alexander. Chrysostom

How craftsmen make shell forms for concrete using the example of a swan for the garden

This method is used by many craftsmen and amateurs to make large numbers of copies (replication) of artificial stone products, as it has a number of advantages:

High precision fragments can be obtained and no additional surface treatment of the cast product is required.
High performance.
Optimal consumption of molding material.

To produce this form, liquid compounds are used. Most often they consist of two components: a base and a catalyst (hardener).

The process of making the mold and then casting is as follows.

The original from which the form will be removed must be cleaned and degreased. If its surface is loose, then it is necessary (as was done when making concrete flowers) to cover it with a layer of varnish, paraffin or wax.

A box is made from suitable materials to accommodate the original.

Plasticine is applied to the lower surface of the original along its contour. The original is then lowered to the bottom of the box and pressed down lightly so that there are no gaps.

The plasticine protruding along the contour is removed with a knife.

Then we cover the entire surface of the original with a layer of plastic film or aluminum foil, onto which we evenly apply a layer of soft plasticine or clay. Smooth the surface.

The average thickness of the top layer should be 8-12 mm. The greater the thickness, the greater the consumption of liquid compound (silicone or polyurethane). But at the same time, the strength of the resulting rubber mold will be higher.

Since the size of a swan significantly exceeds the size of an angel, the thickness of the walls of the flexible form should be greater than the previously obtained 5-6 mm.

Next (more or less what we did with the angel, but with plasticine), we cut out 2-3 dividers from thin plywood or thick cardboard, which we install (by pressing them into the plasticine) between the swan and the walls of the box.

If this is not done, then after filling the space around the swan with plaster or foam, you will have to saw them. Otherwise, the sample may not come out of the “space suit.” In the case of a simple product shape, this may not be necessary.

Pouring plaster

Next, fill the cavity around the swan with plaster or foam.

After the “suit” hardens, the entire structure is disassembled and a sample is taken out.

Once again its surface is checked for cleanliness.

As shown in the figure, it is necessary to make several holes in the formwork (preferably at the highest points of the model) for air outlet and one larger one for pouring the liquid compound.

Pouring compound

Next, we reassemble the entire structure, only without foil and plasticine. We check that the sample is in the middle. We prepare the compound and slowly, so that there are as few air bubbles as possible, pour it in, holding the container close to the mold.

After the compound has completely cured, we disassemble the formwork and remove the swan from the rubber mold. We remove unnecessary tides.

Thus, the shell mold for concrete is ready and now you can proceed to casting a copy of the swan.

Pouring cement mixture

We collect everything again and pour the prepared cement mixture into the mold.

When the concrete hardens (the time depends on the composition of the cement mixture), you can disassemble the formwork and remove the finished product from the mold.