To obtain a sharp small flame, the inner tube is moved closer to the outlet of the cap 4 and the air supply is increased. By removing the nozzle 5 from the outlet, you can get a very noisy, wide, high-temperature flame 8.

When lighting the soldering torch, first of all open gas tap, light the gas and after that turn on the air supply.

If there is no laboratory blower, then use it instead household vacuum cleaner, inserting a rubber stopper with a glass tube and a rubber hose into its outlet. A tee with a piece of rubber tube put on it and clamped with a screw clamp is placed near air valve 1 (see Fig. 37). This will allow excess air to be released when working with low airflow.

If the laboratory has a compressed air network, then the need for blowers naturally disappears.

Cutting glass tubes. To cut a glass tube with a diameter of no more than 12 mm, first make an incision or scratch in a selected place with a diamond, glass cutter or the edge of a triangular file. There is no need to cut the tube around the entire perimeter; one quarter of the circle is enough.

Repeated filing is not advisable, since it only weakens the effect of the first cut. Then take the receiver with both hands as shown in Figure 1, b. Vigorous bending of the tube in the direction opposite to the cut and its simultaneous stretching cause the tube to break along its circumference. It is recommended to pre-wet the incision site with water or an aqueous solution of soap. In this case, the glass breaks off more easily, and the edges of the break are smoother. If a file is used to apply a scratch, then the tube at the cut site should not be sawed, but only a scratch should be made.

To cut tubes with a diameter of more than 15 mm, a scratch is made along the entire circumference of the tube, and then a red-hot iron wire about 3 mm thick and bent in the form of a semicircle is drawn around the tube along the scratch. In this case, a deep crack almost always forms under the scratch, and the tube breaks easily. If a crack does not form, then the tube, after removing it from the wire, is quickly cooled by blowing strongly on the heated part or by directing a stream of air at it. It is more convenient to fix the iron wire in a tripod, heat it up, and then, placing a tube with a scratch on it, slowly rotate it along the cut. After some time the tube breaks.

Sometimes a tube with a diameter of 20-25 mm is cut in the same way as tubes with a diameter of less than 15 mm, but they are broken not by hand, but by placing it on the edge of the table, and the cut should be on top, and the sharp edge of the table should be on the bottom. With one hand they hold the end of the tube lying on the table, with the other they take its other end and, at the same time pulling and bending, break the tube.

Some chemists prefer a different method of breaking the cut tubes. Two asbestos cords of equal length are moistened with water and wrapped around the tube on both sides at the same distance (4-5 mm) from the circular cut, maintaining parallelism between the cords, otherwise the cut will be uneven. Then a sharp flame 7 of the soldering torch is directed to the place of the cut (see Fig. 1, a) and the tube is evenly rotated in the flame until an annular crack is formed. This method is used to cut glass tubes of any diameter from glass of any heat resistance.

If the laboratory has a diamond saw, then it will replace all the above devices for cutting glass tubes.

Thick-walled capillaries and glass rods with a diameter of 3 to 10 mm are cut in the usual way for fracture if their length exceeds 50-100 mm. To cut off a small part measuring 10 mm or less from the capillary, the capillary is placed on

Rice. 2. Bending a glass tube: a - heating in a flame " dovetail"; 6 - incorrectly bent tubes; c - ways to close one end of the tube

one of the sharp edges of the prism (Fig. 1, c) with the cut up so that the edge is exactly under the cut. Then, holding the long part of the capillary with your hand, sharply hit the part that needs to be cut off with a knife. The capillary breaks off exactly along the cut.

The cut edges of the tube are melted in a burner flame or carefully cleaned

a file with a fine notch. However, it is more convenient to grind off the edges. To do this, use an emery disc or emery powder. The powder moistened with water, oil or glycerin is placed on a thick glass plate. The tube to be ground is moved in a vertical position in a circular motion along the plate and at the same time the tube is carefully pressed against it. To obtain a smooth surface, the end of the tube is sanded using a finer sanding powder.

Bending tubes. Tubes with a diameter of up to 30 mm are bent on a gas burner with a wide flat flame, to obtain which a dovetail nozzle is put on the gas burner (Fig. 2, a). The tube is heated in such a flame over its entire width, rotating uniformly at a speed of approximately one revolution per 2 s. After softening, the tube is bent upward outside the flame. Before bending, the tube is stopped rotating in the flame and only heated bottom part softened glass. In this case, a certain amount of glass will flow down into the heated zone - the future outside bending This increases the thickness of the walls of the outer side of the corner. It is not recommended to bend a very softened tube, since a fold will form at the bend (Fig. 2, b). To avoid unevenness at the bend, one end of the tube is covered with a piece of asbestos wool or a piece of rubber tube with a glass rod before heating (Fig. 2, c). When bending the open end of the tube, do not blow too hard

air. Dents from inside The corner is eliminated by reheating the inside of the tube in a flame, blowing it up and leveling it, but the outer side of the corner should not be softened.

To make U-shaped tubes with a diameter of up to 20 mm, the tube is heated with a soft, wide flame, constantly rotating and squeezing the length of the glass slightly more than when bending at an angle. Having received thickened walls, they stop rotating and, bending the tube slightly at an obtuse angle, heat the lower part of the thickened glass. Then the tube is removed from the flame and bent until U shape, holding the heated part down. After bending, the softened part is immediately inflated to a diameter equal to the diameter of the original tube. If the inside of the U-shaped tube is not completely level, then level it on a narrow burner flame, blowing it up and downsetting it.

During operation, the bend area sometimes begins to become cloudy (devitrification). Then a piece of asbestos wool, placed on an iron wire and soaked in a concentrated aqueous solution of sodium chloride, is introduced into the burner flame. The flame acquires a bright yellow color and the flow of NaCl vapor, hitting the cloudy part of the tube, forms fusible glass on its surface, stopping devitrification. Therefore, a glass with an aqueous solution of sodium chloride and a piece of asbestos wool on a wire should always be at hand.

The bent, still hot tube must be smoked in the luminous flame of the burner and placed on asbestos cardboard, protecting it from drafts.

Retracting the tubes and obtaining capillaries is carried out by heating the tube in the desired place while continuously rotating it until softened. If you need to get a capillary, then the tube is removed from the flame and slowly stretched with both hands. Depending on the degree of softening and the rate of stretching, capillaries with different thicknesses walls and diameter. The longer the heated part of the tube, the sharper the cone is obtained when stretched and, conversely, to tighten the tube steeply, it should be heated on a sharp burner flame (see Fig. 1, a). When the tube has cooled, it is cut off at in the right place and melted. When working with glass for the first time, it is recommended that when stretching the tube, hold it vertically, then there will be no danger that the capillary will bend.

Sealing the end of the tube. To seal, first pull off the end of the tube and cut off the resulting capillary 1 (Fig. 3, a). Then the resulting end of the tube is heated again with a sharp burner flame, rotating the tube and without removing it from the flame, the cone of the tube is melted as close as possible to its end (position 2).

Rice. 3. Soldering the end of the tube (a), connecting the tubes (b) and blowing out the ball (c)

After this, the end of the tube is heated in a noisy flame (see Fig. 1, o) and to eliminate the thickening at its end, carefully, using only the cheeks, air is blown into the tube until the correct rounded end is obtained (positions 3 and 4 in Fig. 3 , A). It is necessary to blow in air at a time when the glass is still soft enough and can be inflated.

If the sealed end is not inflated, but a thickening remains (position 3), it may burst when cooling or then after a while.

Connection of tubes. You can only solder the pipes of a loved one chemical composition, having approximately the same coefficient of volumetric expansion and the same softening temperature. Otherwise, the tubes cannot be soldered well or, when cooled, they again disintegrate at the soldering site. All glass tubes must be thoroughly washed and dried before soldering. Contaminated ends of the tubes should be cut off.

To connect, two tubes of the same diameter with evenly cut ends are melted in a burner flame simultaneously (position 2, Fig. 3, b). The second end of the tube, which is held in the left hand, should be closed with a stopper or asbestos swab. As soon as the ends of the tubes begin to narrow after softening, they are removed from the flame, carefully connected so that they form a straight line and pressed against each other. Then the junction is heated over a sharp flame and glass melt is collected (the wall is thickened) (position 3), after which the junction is slightly inflated by 3-5 mm larger diameter source tubes (position 4). This operation is carried out in order to level out the wall thickness as much as possible.

Work on wood and glass Korshever Natalya Gavrilovna

Cutting glass tubes various diameters

When it is necessary to cut a product such as a glass tube, proceed in the following way.

At the location of the required separation, the tube is ground with a file. If the diameter of the tube is more than 1 cm, you must first make a cut over the entire surface, that is, form an even ring. On glass tubes of smaller diameter, it is enough to make a linear cut. But to obtain a smoother cut edge, it is also advisable to grind the tube around. You need to break the treated tube carefully; it is better to wear mittens on your hands.

This text is an introductory fragment. From the book Rules for Electrical Installations in Questions and Answers [A manual for studying and preparing for a knowledge test] author Krasnik Valentin Viktorovich

Usage rate of the main types of insulators and insulating structures (glass and porcelain) Question. How should the utilization factor k of insulating structures composed of similar insulators be determined? Answer. Should be defined as k = ki

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There are several simple ways to trim the neck glass bottle. You may ask why is this necessary? From a beautiful cut bottle you can make a cool glass, a flower vase or a stand for various little things. But, before you start cutting beautiful bottles, I still recommend practicing on ordinary beer bars, since this business requires experience and some dexterity: it doesn’t always work out the first time.

So, I’ll tell you the most simple ways cut off the neck of a glass bottle.

Method 1 - use a glass cutter

Here you will need a glass cutter. Can be used factory model or make it yourself. Design homemade device may be different: the main thing is that the bottle and the cutting element are securely fixed, but the bottle rotates freely.

Important! When cutting, you need to make one pass: this will ensure the most even edge.
Next, you need to prepare hot (boiling water) and cold (with ice) water. First we pour along the cutting line hot water so that the glass warms up well.

After this, immediately pour over the bottle cold water.

Due to temperature contraction, the glass should break off along the preliminary cut line. If this does not happen, the procedure must be repeated (douse it first with hot and then with cold water).

Method 2 - candle flame

This method will require a candle and a piece of ice (you can use a container of very cold water). To break off the neck, draw a straight line on the bottle with a marker, along which the glass warms up well above the candle.

The cutting line is then cooled with ice, after which the glass is cracked by lightly tapping it.

Method 3 - nargev from friction

Another way to break off a bottleneck is to use frictional heating on the glass. To do this, put two plastic ties, which serve as limiters. Three turns of twine are wound between them, after which the twine begins to move forward/backward by the free ends.

After 2–3 minutes, when the glass is hot enough, the bottle is placed in cold water, and when lightly tapped, chipping occurs along the heating line.

If you make a small cut on the bottle with a glass cutter before rubbing with twine, then you do not need to use cold water: the glass will crack when heated on its own.

Method 4 - installation with filament

This method will require a transformer, for example, with microwave oven with the secondary winding removed, instead of which three turns of a powerful power cable are installed.
The free ends of the wire are closed through a thick wire. The stand (base) must be heat-resistant and dielectric.

The next step is to connect the transformer to the electrical network. When you turn on the transformer, the filament will heat up: a bottle is applied to it and gradually rotates. When the glass is heated, the neck along the heating line will disconnect, so you need to make sure that the heating is uniform and along the same line.

Method 5 - burning rope

This method requires natural twine and some refined lighter gasoline. A piece of twine is cut to the length required to wrap around the bottle at least 3 times. This piece of string is then soaked in gasoline until it is completely saturated.

Twine soaked in gasoline is wound around the bottle in the place where it is necessary to chip and set it on fire.

When the gasoline has almost burned out, the bottle is lowered into cold water, where the temperature difference causes the glass to burst along the heating line.

Method 6 - use specialized equipment

This method is to use electric machine for cutting tiles. The diamond blade cuts well and evenly thick glass. It is recommended to work with gloves, a protective mask and goggles, as glass dust is very dangerous. The advantage of using a cutter is the ability to cut the bottle into small pucks, which is not possible with other methods.

... We cut out the bottom of the bottle, I advise you to take 2.3 bottles to practice. I drew lines all over the body of the bottle with a glass cutter and circled the bottom several times, both at the bottom and on the sides, and hit it with a hammer, covering it with newspaper...
I broke off the excess with a glass cutter, this bottom is not good, but there is no other photo.

Raw edges can be hidden in structural units monocle:

***

Option 2:

There is another simple way - cutting glass scissors in water, I used it in my work
With enough experience, you can cut very decent circles.

Option 3:

A simple method for cutting “rounds” from glass is offered in the publication “”

... It turned out that cutting out the glass was as easy as shelling pears. We take the glass, roughly cut it with a glass cutter, bite it with it, then according to the template in a bowl of water with an emery stone we finish it off.

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Option 4:

in his project he cuts out “round pieces” with a special drill:


... The crown is clamped into the chuck drilling machine, the cutting line is immersed in water and at the minimum possible three hundred revolutions per minute, with uniform pressure on the crown, the prepared glass turns into the required goggle round.
After three minutes of leisurely drilling, I got two neat disks of the desired diameter and color. The edges of the discs were processed on a sheet sandpaper with moisture, after which I received completely “branded” glass of three millimeters thickness! It must be said that in the absence of a drilling machine, the successful use of crowns of a similar diameter, in hand power tool, almost impossible.




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I would really like to finish in an original way processing plexiglass, although it does not apply directly to glass, but the method is very good, without straining you can even make lenses:
I spied him at his work

Glue the glass onto a special device. The device is made from a square with Velcro intended for laying wiring, and a bolt.

Drill! And about the skin - in - in - in - life!

result:

Now about tubes, bottles, jars and the like:

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First, about the markings, because it will determine how even your rings will be and how long you will “tinker” with finishing the planes.
Wrap a wide strip of paper (with a straight edge) tightly around your workpiece, as shown in the photo, and draw a line on the glass with a marker (along the edge of the paper):


Now let's start cutting.
Advice: The cutting area must be moistened generously with water.. Everyone will choose their own options, from lowering the workpiece into water, to a thin stream or periodic dipping.
The better the wetting, the cleaner the seam and the fewer chips along the edge.
***

Method 1:

Using a glass cutter and gas burner separates the bottom of a bottle in a master class
...We apply a circular mark using a glass cutter. Accuracy is not so important, the main thing is to try to make the cut continuous... I repeat, we do not need a perfectly even cut, our task is simply to separate the bottom from the bottle.


For the next stage, we will need a propane torch, with the flame of which we will evenly heat the line left by the glass cutter, smoothly rotating the bottle around its axis... The operation must be carried out with gloves and your eyes must be protected with goggles!
If heating proceeds correctly, the process is accompanied by crackling sounds and stops after we hear a muffled click, indicating that the bottle is divided in two by a crack.


***

method 2:

Trou for his project in the competition cut rings with a cutting disc with diamond coating:
But even with such useful tool I follow a few simple rules:
A). Abundant wetting during cutting.
b). To avoid chipping on the back side of the workpiece, I I cut the workpiece on both sides(of course, if it is possible to get to the cutting site).


And if you are the happy owner of a tubular drill and diamond-coated burs, you can cut holes in glass of even “non-traditional” shapes:


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method 3:

Valery (), on the website of our sister cities (tekhnari.ru), found his own way of cutting a fluorescent lamp tube.
Here is a link to his master class. And a few photos to make it clear what we are talking about:


And what happened in the end:


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method 4:

He practices an interesting way of cutting off a light bulb bulb for his
The method is worthy of attention, because part of the base remains on the flask - both beautiful and practical:


***

An exotic, ancient method - we cut out a “spiral” from a bottle

I won’t write anything, I have nothing to add:



***

Drilling holes:

***

example 1:

Pavel () drilled holes with a diamond core bit with a diameter of 4 mm:

Cutting glass tubes, rods, bottles, blanks and flat glass is one of the most common operations in laboratory and glassblowing work. In most cases it precedes all glassblowing operations. Only a correctly cut tube is suitable for further processing (soldering tubes, melting the ends of tubes, soldering extensions, etc.). The cross-section of the end of a correctly cut tube should be strictly perpendicular to its length, and not have any jagged or fibrous parts, as well as short cracks located at a slight angle to the cut site. Depending on the diameter of the tube or workpiece, various ways cutting

Rice. 27. Cutting tubes for fracture

Cutting tubes for fracture. This method is used to cut tubes with a diameter of 20-23 mm and glass rods. In this case, the glass tube is placed on the edge of the table and its protruding part is held with the left hand. In the simplest case, the tube is simply clamped in the left hand. A knife (cutter) made of hard alloy or a sharp file with a fine notch is taken in the right hand. Having placed a cutter or file on the tube in the intended place strictly perpendicular to the length, with your left hand you rotate the tube towards yourself by about a quarter of the diameter (Fig. 27, a). To reduce the surface tension at the cut site, the tube can be moistened with water or a soap solution.

The incision can be made using another method. With your right hand (the tube is clamped in your left hand), place the knife on the tube and, with a slight downward pressure, make a scratch, then push the knife back up, without removing it from the tube, and back down towards you. This creates an even cut equal to a quarter of the diameter of the tube. The incision can be made differently by placing one end of the tube on the right knee and pressing the other end with the left hand to the left leg.

Glassblowers often use the following technique to apply a mark. The glass tube to be cut is grasped tightly with the left hand, holding it between the thumb and index fingers. Take a cutter or file in your right hand (Fig. 27, b). Pillow thumb The right hand should rest against the sharp edge of the file. Then the tube is tightly clamped between the sharp edge of the file and the thumb and a slight turn is made: right hand- towards yourself, and with your left - away from you, making a slot on the surface of the tube.

Beginners learning how to cut glass should use this technique with great caution, since with strong pressure the tube, especially a thin-walled one, can break and injure your hand. After applying the mark, the tube is taken in both hands with the mark; up so that the mark is at the same distance from the right and left hands, and smoothly, stretching the tube in different directions, break it (Fig. 27, c). If the tube does not break, make a second mark on the old mark using one of the indicated methods and break it again. To reduce surface tension, the slot mark is moistened with water. The tube breaks more easily. While students become proficient at cutting pipes, this operation should be done with their hands wrapped in a towel or rag to prevent cuts. When cutting, glass rods are broken with a sharp movement so that burrs do not form on the ends.

If it is necessary to cut the tube close to its end, use the following technique. A deep cut is made on the tube with a cutter, the tube is placed on the edge of the edge of a metal prism or on the edge of a triangular file with the mark facing up. It is necessary to ensure that the scratch applied to the glass falls exactly against the sharp edge of the prism. Then, with a light blow of a knife or file on the short end, it is cut.

Glass rods can be cut in the same way by placing the short end of the rod on the corner of the table.