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Manufacturing technology special
Dissolve 500 g of snow-white soap in 0.5 liters of water; then prepare a solution of 100 g of gum arabic and 300 g of wood glue in 0.5 liters of water; heat both mixtures, drain together and immerse the paper in it. When the latter is well moistened, it is also taken out to allow it to dry at room temperature. The paper treated in this way becomes completely waterproof and can be used as a wrapping paper that protects objects from being wetted by water.
There are other ways: immerse the paper in an aqueous solution of shellac with borax or take 1 part of wood glue and dissolve it in 10 parts of water, add a solution of 1 part of alum in 10 parts of water. The paper is immersed in this hash, but then dried.
In order to make paper waterproof, we recommend impregnating it with an aqueous solution of liquid glue, technical gelatin or casein with 1% formalin.
Preparation of tracing paper
To prepare transparent copy paper, or tracing paper, they dissolve wax in turpentine, impregnate thin writing paper with this solution, and allow turpentine to evaporate, after which the paper is made transparent and ready to use.
The paper can also be made transparent with gasoline: they put fine writing paper on the image from which they want to make a copy and, after wetting a small piece of cotton with gasoline, carry it over the paper. The wetted portion of the paper is completely transparent and can be drawn not only with a pencil, but it looks like ink, but then also with watercolors: neither ink, nor paint does not blur, Gasoline quickly disappears, and the paper retains its initial appearance. If the design is large, then the paper is cut in parts, and the design is copied in parts; gasoline disappears in no way before the work is finished.
Preparation of copy papers
Often used to copy the blue paper, prepared as follows. They take 10 weight elements of good French blue or Prussian blue, crush and pour it with 20 weight parts of vegetable olive oil, to which 1 weight elements of glycerin are added. This mixture is left for a week in a dry, warm place at a temperature of 40-50 ° C. It is also time to stir it, but then, when the French blue is soaked with oil, it is well ground. When the blue dye is thus fully prepared, dissolve over low heat 0.5 weight elements of yellow wax and gradually add to it 1.5 weight parts of petroleum alcohol known commercially as naphtha, after which 3 parts of triturated are added to this last mixture. with french blue oil; heat everything up to 30-35 ° C and also rub it well before the mass is quite homogeneous in consistency. This mass is applied with a wide, soft bristle brush onto the paper, the so-called silk one, and then a wide brush or a flute is used to level the layer so that it is evenly distributed, after which the paper is dried and then it is quite suitable for use.
So that the filter paper does not break through so quickly, which often happens when filtering large quantities of liquid, a simple tool is recommended that, while significantly increasing the strength of the filter paper, doesn’t reduce its filtering capacity at all. This means is that the paper is immersed for a few seconds in nitric acid with a specific gravity of 1.42 and then immediately washed thoroughly in water. The paper prepared in this way can also be washed to knead, as if the canvas; it is made so strong that a strip of ordinary filter paper 5–6 cm wide withstands a weight of 1.5 kg, while the same strip, not subjected to nitric acid, is broken by the weight of 150 g, i.e. . ten times less durable.
The filter paper, as it is known, has a flaw, consisting in the fact that through it the fluids are filtered relatively slowly, in particular, more or less viscous and viscous consistency. This disadvantage is especially noticeable at what time a significant number of the above fluids are filtered. In these cases, the filter paper can be successfully replaced with suede. A piece of suede is soaked in a weak soda solution to remove the fat contained in it, and then rinsed thoroughly in cold water. Thus prepared suede is used as a filter paper. Through it, not only all kinds of tinctures, but also very thick syrups, are also very cleanly filtered, however, it seems that the viscous, slimy vegetable juices seem to be. About the speed of this process can be discussed already by the fact that the liter of the most viscous syrup is filtered in 15 minutes. Another important plus of filter suede is that it can serve for a very long time; you only need to rinse it thoroughly after each use.
How to restore faded ink on parchment
To do this, it is enough to cover the parchment with which the ink came off, with a brush to cover it with a layer of ammonium sulfide. This tool has been tested long ago and has been successfully practiced by the Oxford Library in appropriate cases.
Washable work drawings
It has long been known that the drawings in the workshops are made so dirty over time, and it is also unclear that the numbers indicated on them and the dimensions can often not be disassembled. In order to protect drawings made in ink or in pencil from contamination, we advise you to put them on glass or on a plank and also cover them with collodion, in which 20% of stearin is added. After 15 minutes, it dries out and also alienates the pure white color with a matte gloss. Thus, the drawing is covered with a protective layer, which can be washed with clean water, without fear of washing the figures as well.