Manufacture of gypsum products - with what do we have to work?
Several types of such a powdery substance are produced. Distinguish medical, high-strength autoclave and construction( called an old-fashioned alabaster) gypsum. The produced material is marked with the letter G with digital indexing, which shows the compressive force maintained by the mark. The higher the index, the better the indicator.
Indices from five to twenty five are attributed to building alabaster. The best brand( autoclave) easily withstands two hundred and fifty kilograms for compression and is labeled G-250.The last type of material is considered to be the least suitable for products. But it is widely used in construction as a component that provides a quick grasp of putty solutions( calc-gypsum).
Due to the high setting speed, only a small portion is prepared for one operation. However, the compositions that slow down the setting can increase the operating time. One of them is animal bone glue. For example, a good solution for spreading cracks can be prepared from one part of such a construction gypsum, two parts of chalk and a 5% bone glue, with which the sieved mixture is bred to the working density.
Manufacture of gypsum products is best done using an autoclave high-strength type( it is preferred by dental prosthetics), but the medical appearance is also suitable. In general, they are often used for molding and casting all kinds of panels, architectural details, facing plates and other products in medicine, as well as in construction, and other industries.
Proper use should take into account the property of the material to increase its volume to one percent when curing. The powder has a certain shelf life and gradually loses its ability to harden over time.
The technology for making gypsum products - the basic rules of
When gypsum products are created, the technology must be strictly observed, from mixing to casting. If the rules of production are not observed, the products may have various voids, shells, or even fall apart at all. The amount of ingredients is taken by volume.
So, in the dishes for the preparation of a solution, one part of the water is poured not warmer than twenty-five degrees Celsius. By the rules, it's impossible to pour water into the powder. On the contrary, the material is poured into it in a volume of two to two and a half parts with constant vigorous stirring. Should get a solution with the density of homemade sour cream.
During preparation, the composition is constantly tapping to remove air bubbles from it. It should be noted that the diluted test is unlikely to work out anything. It hardens too quickly and is therefore used for casting. Here and the closed mix it is necessary to pour out in the prepared form with the walls covered with a dividing structure.
This formulation is prepared from a saturated soap solution or a heated petrolatum or other oil. Usually the solution begins to harden in the fourth minute, and after that it becomes completely solid. The process continues for about a day, by this time the product will gain the necessary strength.
Decorative articles from gypsum - small secrets for good quality.
. The technology of making gypsum products provides the opportunity to accelerate or slow down the hardening of the composition. At the same time acceleration is considered as deteriorating the properties of the product factor and it is rarely used. Slow down, on the contrary, positively affects the quality of the castings produced and is widely practiced.
Hardening is slower, and the final strength of the product increases if the closure is performed on solutions of borax, sugar, ethyl alcohol or, as already mentioned above, bone glue. These closers are prepared on water with a concentration of three to six percent, depending on the substance chosen. The volume parts of the powder are the same.
By the way, if the fully cured product( on water without a retarder) boils for twenty minutes in the already mentioned borax solution, its strength increases. You can prepare a good shape from talc, which is mixed with PVA or silicate glue. Instead, it is also suitable for rubbing red brick or small porcelain crumb.