|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
ENTERTAINING EXPERIENCES AT HOME
Glass and enamel. Chemical experiments
Entertaining experiences at home / Chemistry experiments for children Badges, brooches, various jewelry and many household items are covered with enamel - glass applied to metal. So we will try to make glass. These experiments require a special oven. For this reason alone, glass production cannot be done at home. But, in addition, skills in working with hot melts are also needed, so experiments, of course, must be carried out in the presence of seniors. In factories and chemical laboratories, glass is produced from a charge - a thoroughly mixed dry mixture of powdered salts, oxides and other compounds. When heated in ovens to a very high temperature, often above 1500 °C, salts decompose into oxides, which, interacting with each other, form silicates, borates, phosphates and other compounds that are stable at high temperatures. Together they make up glass. We will prepare so-called fusible glasses, for which a laboratory electric furnace with a heating temperature of up to 1000 °C is sufficient. You will also need crucibles, crucible tongs (so as not to get burned) and a small flat plate, steel or cast iron. First we will weld the glass, and then we will find a use for it. Mix with a spatula on a sheet of paper 10 g of sodium tetraborate (borax), 20 g of lead oxide and 1,5 g of cobalt oxide, sifted through a sieve. This is our batch. Pour it into a small crucible and compact it with a spatula so that you get a cone with the top in the center of the crucible. The compacted charge should occupy no more than three-quarters of the volume in the crucible, then the glass will not spill. Using tongs, place the crucible in an electric furnace (crucible or muffle), heated to 800-900 °C, and wait until the charge is fused. This is judged by the release of bubbles: as soon as it stops, the glass is ready. Remove the crucible from the furnace with tongs and immediately pour the molten glass onto a clean steel or cast iron plate. Cooling on the stove, the glass forms a blue-violet ingot. To obtain glasses of other colors, replace cobalt oxide with other coloring oxides. Iron (PI) oxide (1-1,5 g) will color the glass brown, copper (I) oxide (0,5-1 g) - green, a mixture of 0,3 g of copper oxide with 1 g of cobalt oxide and 1 g iron (III) oxide - black. If you take only boric acid and lead oxide, the glass will remain colorless and transparent. Experiment yourself with other oxides, for example, chromium, manganese, nickel, tin. Grind the glass with a pestle in a porcelain mortar. To avoid injury from the fragments, be sure to wrap your hand in a towel and cover the mortar and pestle with a clean rag. Pour fine glass powder onto thick glass, add a little water and grind until creamy with a chime - a glass or porcelain disk with a handle. Instead of a chime, you can take a small flat-bottomed mortar or a polished piece of granite - this is what the old masters did when they ground paints. The resulting mass is called slip. We will apply it to the surface of aluminum in much the same way as they do when making jewelry. Clean the aluminum surface with sandpaper and degrease by boiling in a soda solution. On a clean surface, draw the outline of the design with a scalpel or needle. Using a regular brush, cover the surface with slip, dry it over a flame, and then heat it in the same flame until the glass is fused to the metal. You will get enamel. If the icon is small, it can be covered with a layer of glass and heated entirely in a flame. If the product is larger (say, a sign with an inscription), then you need to divide it into sections and apply glass to them one by one. To make the enamel color more intense, reapply the glass. In this way, you can obtain not only decorations, but also reliable enamel coatings to protect aluminum parts in all kinds of devices and models. Since in this case the enamel bears an additional load, it is advisable to cover the metal surface with a dense oxide film after degreasing and washing; To do this, it is enough to hold the part for 5-10 minutes in an oven with a temperature just below 600 °C. Of course, it is more convenient to apply slip to a large part not with a brush, but with a spray bottle or simply by watering (but the layer should be thin). Dry the part in an oven at 50 - 60 °C, and then transfer it to an electric oven heated to 700 - 800 °C. You can also make painted plates for mosaic work from fusible glass. Cover pieces of broken porcelain (they will always be given to you at a china shop) with a thin layer of slip, dry at room temperature or in an oven and fuse the glass onto the plates, keeping them in an electric oven at a temperature of at least 700 °C. Having mastered working with glass, you can help your colleagues from the biology club: they often make stuffed animals, and stuffed animals need different-colored eyes... In a steel plate about 1,5 cm thick, drill several recesses of different sizes with a conical or spherical bottom. In the same way as before, fuse the different colored glasses. The gamma is probably enough, but to change the intensity, slightly increase or decrease the content of the coloring additive. Place a small drop of brightly colored molten glass into the recess of the steel plate, then pour in the iris-colored glass. The drop will enter the main mass, but will not mix with it - this way both the pupil and the iris will be reproduced. Cool items slowly, avoiding sudden temperature changes. To do this, remove the hardened but still hot “eyes” from the mold with heated tweezers, place them in loose asbestos and cool them to room temperature. Of course, fusible glass can also be used in other applications. But wouldn't it be better if you look for them yourself? And to complete the experiments with glass, using the same electric furnace, we will try to turn ordinary glass into colored glass. A natural question: is it possible to make sunglasses this way? It is possible, but it is unlikely that you will succeed the first time, because the process is capricious and requires some skills. Therefore, take up glasses only after you have practiced on pieces of glass and made sure that the result meets your expectations. The base paint for glass will be rosin. You previously prepared driers for oil paints from resinates, acid salts that make up rosin. Let us turn again to resinates, because they are capable of forming a thin, even film on glass and serving as carriers of coloring matter. Dissolve pieces of rosin in a solution of caustic soda with a concentration of about 20%, stirring and remembering, of course, caution until the liquid turns dark yellow. After filtering, add a little solution of ferric chloride FeCl3 or other ferric salt. Keep in mind that the concentration of the solution should be small; salt cannot be taken in excess - the precipitate of iron hydroxide that forms in this case will interfere with us. If the salt concentration is low, then a red precipitate of iron resinate is formed - this is where it is needed. Filter the red precipitate and dry it in air, and then dissolve it until saturated in pure gasoline (not automobile gasoline, but solvent gasoline); it would be even better to take hexane or petroleum ether. Using a brush or spray paint a thin layer of glass on the surface, let it dry and place in an oven heated to approximately 5 °C for 10-600 minutes. But rosin is an organic substance, and it cannot withstand this temperature! That's right, but that's exactly what you need - let the organic base burn out. Then a thin film of iron oxide will remain on the glass, well adhered to the surface. And although the oxide is generally opaque, in such a thin layer it transmits some of the light rays, i.e., it can serve as a light filter. Perhaps the light-protective layer will seem too dark to you or, on the contrary, too light. In this case, vary the experimental conditions - slightly increase or decrease the concentration of the rosin solution, change the firing time and temperature. If you are not satisfied with the color in which the glass is painted, replace the ferric chloride with the chloride of another metal, but certainly one whose oxide is brightly colored, for example, copper or cobalt chloride. And when the technology is carefully developed on pieces of glass, it is possible to transform ordinary glasses into sunglasses without much risk. Just remember to remove the glass from the frame - the plastic frame will not withstand heating in the oven in the same way as the rosin base... Author: Olgin O.M.
▪ jet ship
▪ Color pictures using liquid glass (or silicate glue)
Artificial leather for touch emulation
15.04.2024 Petgugu Global cat litter
15.04.2024 The attractiveness of caring men
14.04.2024
▪ iPhone predicts the desires of the owner ▪ Converting coal to anode grade graphite ▪ Learning outside of school is more useful ▪ Honor Earbuds 3i Wireless Headphones
▪ section of the site Electricity for beginners. Article selection ▪ article Drawers in the bathroom. Tips for the home master ▪ article What poet could not create without the smell of rotten apples? Detailed answer ▪ City bike article. Personal transport ▪ article Sheepskin, fur. Simple recipes and tips
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
We recommend interesting experiments in physics:
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page