How to breed plaster cast?

Plaster of paris is widely used in renovation work. It can be used as part of special solutions, acts both as an astringent component and as an independent finishing material. Gypsum consists of a homogeneous white powder of a grayish shade, enhanced by adding water in a certain proportion. This type of gypsum is called alabaster. Substance forms a dry mixture of components.

A properly diluted mixture will be the key to successful repairs. To dilute gypsum, it is necessary to prepare a disposable clean container, preferably plastic or rubber, which must be filled with the required amount of water. Next, you should measure the required proportion of gypsum and carefully pour it into the prepared container.

It is important to avoid lumps during the mixing process. It is necessary to evenly distribute the gypsum over the surface of the liquid, then wait a few minutes, as the powder must be soaked in water. After that, for 2-3 minutes, you need to stir the solution vigorously until a homogeneous composition is obtained. The consistency should be creamy.

After the completion of stirring, the alabaster sets, and after 4-6 minutes the solution begins to harden. Completely the composition hardens within 30 minutes after production. For this reason, the prepared solution is preferably used directly after mixing with water.

Plaster of paris is often used in the elimination of cosmetic defects on walls and ceilings. A mixture of alabaster is the best option for filling surfaces in rooms that have a normal level of humidity, since gypsum actively absorbs excess moisture. In addition, alabaster mortar is used in repair work to seal up cracks. With its help, you can prepare a plaster solution for the walls.

To seal the holes, you must first clear the formed crack and impregnate this place with a primer using a paint brush. Next, you can rub in the prepared solution using a spatula. Then put a self-adhesive tape-serpyanka on the sealed hole.

If gypsum needed to be poured into molds, then in order for the material to take the required shape, it is necessary to adhere to a certain proportion in the manufacture of the solution. It is recommended to mix gypsum with liquid in a ratio of 7: 10. This ratio allows you to get a fairly liquid consistency, which is especially important when the gypsum hardens in the desired form. However, the product may come out too brittle, so two tablespoons of PVA glue should be added to the composition.

The setting speed of gypsum directly depends on the grinding, the presence of impurities in the composition, the manufacturer and the proportions of added water. As the gypsum hardens, it grows slightly in size, while releasing a small amount of heat. This useful property helps to fill all cavities.

If you want to get a high-strength gypsum solution, it is recommended to dilute the powder with water in a ratio of 2: 1. If you need a medium-soft solution, then use 1 liter of water per 1.5 kg of gypsum powder. When a more liquid solution is needed during construction work, the best solution is to dilute gypsum in a 1: 1 ratio.

When mixing gypsum with lime, it is important to observe the correct proportions, otherwise the wall covering will be translucent (if the concentration is insufficient). With excess, bubbles will begin to form on the surface, and the gypsum will fall off the wall. The proportions are chosen based on the surface area to be processed. For every 2.5 m2, you need to take 0.5 kg of lime and dilute the mixture in 0.75 liters of water.

Before starting the application, care should be taken to ensure that the surface is completely cleaned of various dirt and old coatings. If necessary, apply plaster and primer to uneven surfaces.

For small volumes of work, it is better to take a stainless steel spatula or a hardwood stick. If the coating has a large area, it is preferable to use an electric mixer with a special attachment. Gypsum should be diluted in small volumes so that the solution does not have time to deteriorate before the work is completed.

It is also recommended to use cold water so that the resulting mixture does not harden too early. It should be remembered that the powder is added to the liquid, and not in the reverse order. The gypsum must be soaked in water, in which case the time of its use will increase. When the setting process of the solution is started, the addition of individual components is unacceptable, otherwise the finished composition will be spoiled and unsuitable for use.

To slow down the setting of the gypsum solution, you can use special agents. For example, add a low concentration adhesive solution to the mixture. To do this, it is better to purchase CMC wallpaper glue or wood glue. The dosage of the glue should be 2% of the total mass of the solution. To speed up the setting, you can thin it with hot water, or add 1-4 grams of table salt for every liter of liquid. Also, folk methods suggest adding 100 grams of drying oil per liter, which will lead to an extension of the plasticity of the material.

Before purchasing an alabaster mixture, it is recommended to study the instructions on the package indicating the proportions for creating a gypsum solution. High-quality material is easier to find from large manufacturers that have established production.

How to breed gypsum, see the video below.