In the manufacture of incendiary tubes (IT), only the OH that has been previously tested for the burning rate is used.
They check it like this: cut off the end of 10 – 15 cm from the bay (if the OSh bay is supposed to be used completely in this episode of blasting, the second end is cut off in the same way), then measure, cut off and ignite a 60 cm long segment of the OSh, marking in the second hand ignition time.
If the segment burns within the limits of 60 to 70 s, the OSH is suitable for use; if it burns faster or slower, the cord is considered unusable, and the entire bay is destroyed by burning.
In the manufacture of SP at the site of blasting, it is necessary, first of all, to prepare a segment of the OSH of the required length. The length of the OSH segment is determined when one explosive charge is detonated by the time required for the explosive to move to a safe distance from the charge (or to the shelter), and when several charges are detonated, the time required to ignite all incendiary tubes and for the subsequent departure of the explosive to a safe distance.
For blasting charges located, for example, in the ground, the length of the OSH segment must be such that the end of the cord with a length of at least 25 cm comes out of the ground for ease of ignition.
|With a dry sharp knife (preferably on a wooden lining and in one motion, so as not to soak the cut and not pour out the gunpowder from the core of the OSh), cut off a piece of the igniter cord of the required length so that the cut is at a right angle from one end, and at an angle as possible from the other sharper, but not less than 45°. The sharper the flammable end of the HO is cut off, the more the powder core is exposed, the more convenient the match will fall on it when ignited, and the more reliable the OH is ignited.|
|Then the CD is taken out of the box and its suitability is checked by inspection. If defects are found in it, they are rejected. If a speck has got into the CD, it is removed by lightly tapping the muzzle on the fingernail. It is forbidden to remove specks from the cartridge case of the CD with any objects (even a straw) so as not to cause detonation of the initiating explosive, and also to blow them out, since moisture can get into the detonator cap, which can moisten the core of the cord, and this will lead to failure of the incendiary tubes.|
|The end of the OSH, cut at a right angle, is carefully inserted into the sleeve of the CD until it stops in the cup. The cord must be inserted into the sleeve easily, without pressure and rotation, which can lead to an explosion of the CD. If the cord enters the sleeve too freely, the end is wrapped with one layer of electrical tape or paper.|
After that, to fix the CD on the igniter cord, the CD is crimped. To do this, take the cord in your left hand and, holding the CD with your index finger, apply a crimp with your right hand so that its lower surface is at the level of the sleeve cut, and even more conveniently, so that the sleeve cut protrudes 1-2 mm below the crimp surface – then it is easier to control single compression level.
Then the sleeve of the CD is crimped, after each pressing, opening the crimp and slightly turning the incendiary tube in the open crimp or turning the crimp around the still held ST. Increasing the force with each pressing, it is necessary to achieve the formation of an even annular neck on the sleeve of the CD, which ensures the strength of the connection of the CD and OSh. It is impossible to press with a crimp on the place of the CD where the explosive is placed.
Crimping CD can only be done by crimping. If there is no crimping, then the end of the OSh inserted into the CD should be wrapped with insulating tape or (if there is no tape) with paper so that the cord does not fall out of the sleeve under its own weight.
The correct articulation of the CA with the OH is a very important condition that ensures the failure-free operation of the blasting, therefore, in the manufacture of the ST, the following must be especially carefully observed:
- perpendicularity of trimming the end of the SH entered into the CD with respect to its axis
- tightly bringing this end of the cord to the KD cup
- strong enough, but without clamping, compression of the sleeve of the CD on the OSh
If the end of the cord inserted into the sleeve of the CD is cut obliquely or not brought to the cup, then the core of the cord will be at some distance from the hole in the cup, and sparks flying out of the end of the cord when it burns out, overcoming the air gap between the powder core of the cord and the initiating explosive the substance of the detonator cap, will lose their strength (force and pungency) and may not excite the detonation of the CD.
The weak fastening of the cord in the sleeve of the CD creates the possibility of the end of the cord moving away from the cup when handling the incendiary tube.
On the contrary, with a very strong compression with the formation of a deep neck on the sleeve, the powder core of the OH can be displaced (torn) by a highly compressed sheath of the cord, and its burning will end at the point of rupture; explosion of the CD will not occur.
When using incendiary tubes in damp places and during underwater explosions, the junction of the cord with the CD is covered with insulating tape.
If the incendiary tube is not used immediately, especially in wet weather, its free end is also covered with electrical tape, which is removed only before applying ST. If in this case there is no electrical tape, the ST should be made a few centimeters longer than the calculated value in order to cut off these few centimeters of the SB before use, which could be damp from the end even during short-term storage, for example, in a dry bag.
It is impossible to manufacture incendiary tubes in the places of storage and issuance of explosives, as well as closer than 25 m from the location of explosives and charges from them. OSh, KD and ST must not be placed on the ground even in dry weather. In rainy weather and during snowfall, incendiary pipes should be made under a canopy, in tents or under a cape. If several blasters are involved in the manufacture of incendiary tubes, they must be at least 5 m apart from each other.