For performance of stucco mouldings of facades is better to use open glutinous forms. These forms differ from plaster bolshej elasticity that gives the chance to receive casting of the most difficult models. Besides glutinous forms are reusable - with their help it is possible to make to 60 copies.
Before the work beginning it is necessary to prepare model correctly. It establish and fix on a support in which quality usually use a plaster plate. From edge of a plate to model there should be a distance in 5-6 see Having receded 2 sm from plate edge, it is necessary to fix stenochki from a tree, a cardboard, clay or metal. They are used that liquid glue did not spread on all plate. Therefore stenochki should be above the highest point of model at least on 1-2 sm ( fig. 35 ).
a Fig. 35. Manufacturing of the open glutinous form :
1 - clay prodab; 2 - model; 3 - stenochki; 4 - a plate.
If stenochki adjoin to a plate leaky it is necessary to fill intervals with clay. Now and stenochki from within it is necessary to cover the strengthened model, a plate with greasing, to wait about 20 minutes and to remove the rests of greasing a brush. On the prepared model traces from brush movements should be visible.
Glue for pouring should be heated up till 45-55 °s. The glue temperature cannot be exceeded in no event, differently it will kindle greasing on model. With hot glutinous weight completely cover model, trying not to pour a liquid through stenochki. In 10-12 hours glue will fall asleep, then it is possible to clean stenochki and to start branch of the form from model.
By means of the form it is possible to receive about 5 copies. Raw glutinous forms are short-lived, as from heating by plaster they are melted off, and because of glue drying up harden and lose the relefnost. To save the form from deformations and destruction it is possible, having subjected to its special processing.
The taken off uniform strew talc to degrease its surface, and then tan (wash out in the cool sated solution of alum). The surface processed by talc quickly absorbs alum. After that it is necessary to examine attentively the form and if in deepenings there was a superfluous glue, it accurately delete. Having dried the form within an hour, it repeatedly tan and leave on an equal surface at 5-6 o'clock.
The Given form has one lack: because of the elasticity she repeats all roughnesses of a surface. Therefore at storage and operation it should be in a special case which very simply make. For this purpose the form put on model, cover with greasing and make in it poles in diameter about 1 sm and depth 0,5-1 They see are necessary for its strengthening in the future case.
Then the form cover with plaster on 3 sm, entering into it armature for case strengthening. It is important to track that the top surface has turned out flat, differently it will be impossible to take advantage of the form.
The Case can be removed from the form only after full hardening of a plaster solution. That the form did not become impregnated with a moisture from otlivok, it is necessary to cover an internal surface of a case in some layers shellakovym spirit with a varnish. Now the case and the form are ready to use.
Before the beginning of work the form and edges of a case by means of a brush cover with greasing. So arrive before each casting. If for a facade ornament running details are used, at their casting it is necessary to make a skeleton. The form thus fill with the first layer of a plaster solution very quickly, slightly it shaking. If the form remains motionless in a product air vials can be formed that will negatively affect its durability. Without allowing to fall asleep plaster, on all length of the form (which should not exceed 40-50 sm) lay a skeleton and close its second layer of a solution, filling the form to edges. Turned out surface is necessary for levelling accurately.
After full hardening of plaster the form should be put on an equal surface and to remove a case. The form will easily separate from a product if to undertake it two hands, to press fingers its back part and to curve.
For manufacturing of the socket the form fill with plaster on 2-3 sm, slightly it shaking. As a skeleton it is possible to use the hemp soaked in a plaster solution, or dran. In the latter case armature spread in the form squares with the party 3-4 see After that the form fill in completely, a surface level and wait for full hardening of plaster. To take a product from the form it is the most convenient in vertical position. Thus it is necessary to avoid sharp movements, differently it is possible to damage both the form, and casting.
The Finished article spread on an equal surface and if it is necessary, correct defects. The form carefully clear of the plaster rests, cool and stack in a case.
If necessary it is possible to subject the Received decorative elements to processing which will raise their durability. Also it will help elements to be entered in the general architectural decision of a facade organically.
It is possible to return Broken away pieces of a product into place by means of gluing. For this purpose in the broken off part it is perpendicular to edge the deep and narrow furrow reaching the middle of a piece is cut. The same furrow is necessary for making and in casting. In furrows fill in plaster, connecting details a skeleton from a wire. On a connection line impose a thin layer plaster, and product parts press to each other. When plaster will fall asleep, its surpluses on a seam need to be removed.
If the air vial on a product there can be small cones in shape was formed. They are simple for removing a knife or a chisel then the surface should be smoothed out a glass skin. .
Superfluous deepenings from a product leave by oshkurivanija. It is necessary to humidify and fill deep poles with a plaster solution an elastic soft brush. At work with the big products plaster impose a shovel. The dried up surface smooth out a skin.
Any ornament for facades from plaster should be steady against moisture influence. To achieve it it is possible in several ways.
- the Product heat up to 50 - 60 °s. And by means of a brush cover with the drying oil having temperature nearby 30 °s. When drying oil ceases to be absorbed, an ornament detail leave for drying in a dry place on 2 - 3 days and after that cover shellakovym with a varnish twice.
- It is possible to prepare 100%-s' solution kalievyh or aluminium alum or 25%-s' solution of formalin and to leave in it a plaster product for 30 minutes. It is necessary to repeat procedure 2-3 times.
- the Decorative element from plaster will get durability if it on 15 minutes to ship in 10%-s' solution copper kuporosa. After that the product should be dried within several minutes and again to ship in a solution for 10 minutes, having repeated this procedure twice. Between immersings a product necessarily dry.
- the Brush put on a product 5%-s' solution of chloride calcium, dry within 5 minutes and some time hold in a soap solution.
At desire of an ornament from plaster it is possible to paint, simulating marble, bronze, pig-iron, an ivory. However to add paints in a plaster solution before its pouring in forms much easier. In this case paints from natural materials are usually applied: soot, ohry, mummies, an ultramarine, umbry. But after drying it is necessary to impregnate such product well with drying oil as impurity reduce durability of plaster. .
Finished article Colouring is called patinirovaniem. Before to start this process, the cast product needs to be processed carefully. At first it is necessary to be convinced that the ornament detail has well dried out, as the oil paint will not keep on damp plaster. Then a product by means of a wide brush cover nagretoj with drying oil or spirit shellakovym a varnish twice. Any figure from plaster it is possible tonirovat the usual oil paints mixed with a varnish or drying oil. For this purpose the product is covered with tone with 3 times. .
If the ready ornament for a facade has to simulate an ivory the desirable effect can achieve, having executed some simple operations. At first on a product a brush put a solution from 1 l of hot milk and 30 g white soap and accurately shade, avoiding formation of strips. After drying a surface ground an oil varnish which gives it a pale yellow shade. Every other day on a varnish put a yellow oil paint and at once clean its rag from a soft material. The surface processed thus will strongly shine. It is possible to get rid of superfluous shine by means of talc and shchetinistoj brushes. .
Well impregnated with drying oil and the dried up product simulates marble. It is possible to replace impregnation by drying oil with immersing in capacity with hot paraffin and if to add corresponding colouring it is easy to achieve patinirovanija under a tree, a stone etc.
For imitation of a terracotta a product subject to processing by drying oil, a varnish or a soap solution and cover with oil paints twice. If oil paints to dissolve with turpentine in which the wax slice the surface becomes matte before has been dissolved. .
It is possible to mix ohru, whitewash, soot, drying oil and sikkativ. The received dark grey ground put on decorative elements from plaster for pig-iron imitation. As soon as the ground will dry up, it is necessary for processing a powder consisting of a mix of a mummy, ohry, graphite, whitewash and an ultramarine.
Ornaments of facades of the buildings, executed under bronze very effectively look. A paint of the necessary tone receive from a mix of oil paints of different colours and equal parts of turpentine and sikkativa. A product coat and dry up. Then a few wax dissolve in turpentine and put over a paint. The bronze powder which a thin layer put on drying up wax in advance should be prepared. A brush with which help a product cover with a powder, it is necessary to moisten in the kindled wax. That the ornament has got characteristic for bronze metal shine, it process a soft rag.
There is one more way of reception colouring under bronze. For its application on a detail put drying oil. A bronze powder oxidise a solution ljapisa, and put this mix on a surface after vpityvanija drying oils. In the end of work a product cover with wax and wipe a soft rag.
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