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Файл:Processing Techniques for Different Furs. Tutorial
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Wet-salted skins go to the stage of preliminary washing at a temperature
of 25 ºС for 60 minutes in the presence of 0.5 g/dm
3
of Foryl LHTs-S. Then,
the skins are washed. After the washinf solution is drained out, the soaking
process is carried out at 25 ºС for 10–12 hours). The composition of the bath
is: Atezan LPV (1.0 g/dm
(0.3 g/dm
3
). Then, the skins are washed, sammed in a centrifuge, sheared,
and fleshed. Next, they are soaked again at 25 ºС for 10–12 hours. The composition of the bath is: Atezan LPV (1.0 g/dm
Preventol VB (Bayer) (0.3 g/dm
3
); Foryl LHTs-S (1.0 g/dm3); sodium carbonate
3
3
). Finally, the solution is drained out and
); Foryl LHTs-S (0.5 g/dm3);
the skins are washed and fleshed.
Before pickling, the operations of cleaning and degreasing are carried
out at a temperature of 38 ºС for 1.5 hours. The composition of the bath is:
Foryl LHTs-S (1.5 g/dm
After washing at 30 °C, the skins are sent to the stage of pickling (temperature – 30 °C, duration – 16–18 hours). 50.0 g/dm
added to the bath. After 30 minutes, 2.0 g/dm
60 minutes, 8.0 g/dm
3
); sodium carbonate (0.5 g/dm3).
3
3
3
of formic acid is added. After 60 minutes, sulfuric acid
of Pellan GLS is added. After
of sodium chloride is
is added into the bath. The pH at the end of pickling should be 2.8. After
pickling, the skins are ageing for 12 hours.
The next process is tanning. It is carried out at 25 °C for 14–18 hours.
To prepare the bath composition, 50.0 g/dm
ter 10 minutes, 2.0 g/dm
of Tannit LTSR is added. After 30 minutes, 8.0 g/dm
2.0 g/dm
3
of liquid Pellan GLH, and 2.0 g/dm3 of Tannit LSV are added.
3
of Pellan GLS is added. After 30 minutes, 6.0 g/dm3
After 3 hours, a second portion of a chromium tanning agent (12.0 g/dm
the same basicity is dosed. After 1 hour, 3.0 g/dm
3.0 g/dm
3
sodium bicarbonate (in four doses of 20 minutes) are added into
3
of sodium chloride is used. Af-
3
of 33% chromium salt,
3
3
of sodium formate and
) of
the bath. The pH at the end of tanning should be 3.8. After the solution is
drained out, the skins are washed and sent to the stage of ageing for 24–
48 hours. Next, the skins go to the stage of wet buffing. Further, neutralization is carried out at 35 ºС for 2 hours in the presence of sodium formate
(3.0 g/dm
3
) and sodium bicarbonate (2.5 g/dm3). The pH is 4.5 for a skin cut,
and 6.0 for working solution.
Next process is greasing. It is carried out at 50 ºС for 1.5 hours.
The composition of the bath is: Pellan GLH liquid (4.0 g/dm
(3.0 g/dm
3
); Sirial TIS (1.5 g/dm3); formic acid (0.5 g/dm3). The solution pH
3
); Sirial OFB
is 4.0. After washing, the skins are ageing for 12 hours. Then, they are
sammed, dried, moistened, staked, napped, and clipped. The operation of
hot-pressing is carried out once or twice at a temperature of 180 ºС in
the presence of Kutafix RF (100 cm
3
per 900 cm3 of water).
Next, haircutting, degreasing with perchlorethylene or trichlorethylene
for 6 minutes, drying, moisturizing, staking and buffing are performed.
These processes are followed by dyeing and greasing. Retanning is carried out at 35 ºС for 4 hours in the presence of 3.0 g/dm
liquid. After 30 minutes, 1.0 g/dm
LTSR are added. After 2 hours, a chrome tanning agent of 33% basicity is
dosed in an amount of 5.0 g/dm
3
of Sirial TIS and 5.0 g/dm3 of Tannit
3
. After 1.5 hours, 2.0 g/dm3 of sodium for-
3
of Pellan GLH
mate (pH 4.0) is added.
After washing, neutralization is carried out at a temperature of 35 ºС for
1.5 hours. The composition of the bath is: Tannit KNS (2.0 g/dm
bicarbonate (2.0 g/dm
is carried out at 65 ºС for 2.0–2.5 hours. Doregal PEV is dosed into the bath
in an amount of 1.5 g/dm
(pH 4.5–5.0) is added. After 30 minutes, the dissolve Dorapel C dye is dosed.
After 1 hour, 1.5 g/dm
After washing, skin dyeing is carried out at a temperature of 30 ºС for 3.5
hours in the presence of ammonia (1.0 g/dm
GLH (1.0 g/dm
added. After 45 minutes, Coratil 4385 (0.5 g/dm
3
g/dm
), and Sirial TIS (2.0 g/dm3) are added into the bath. After 45 minutes,
85 % formic acid is dosed in two portions with an interval of 20—30 minutes
(1.0 g/dm
3
and 2.0 g/dm3, respectively). The solution pH is 3.6.
After washing, the skins are sent to the stage of hot-pressing, which is
carried out once or twice at 180–200 ºС. 200 cm
Antistatic L 6, 25 cm
700 cm
3
of water to prepare the working solution. Next, the operations of
3
, pH 5.0 for the skin cut). After washing, hair dyeing
3
. After 20 minutes, 0.2 g/dm3 of 85-formic acid
3
of formic acid is added. The solution pH is 3.5–3.8.
3
3
), Tannit LP 1 (1.0 g/dm3) and Doranil Fast P (x g/dm3) are
3
of Glanzlyuster S, 50 cm3 of alcohol are added to
). After 10 minutes liquid Pellan
3
), Pellan GLH liquid (3.0
3
of Kutafix RL, 25 cm3 of
3
); sodium
haircutting and sorting are carried out. Finally, the skins are delivered to
the warehouse.
42
43
1.2. Winter types of fur raw materials
Winter types of fur raw materials include skins of rabbits, dogs and domestic cats. The skins of these adult animals are of the highest quality in
winter.
1.2.1. Rabbit skins
The fur industry processes a large amount of rabbit skins. There are
about 60 breeds and breed groups of rabbits. Rabbit skins account for 10 to
15 % (by area) of semi-finished products produced by the fur industry. Depending on the fur quality, rabbit skins are divided into fur skins and wool
skins. The main features of fur skins are high elasticity of the hair. Wool
skins have a long, soft and slightly elastic hair.
Rabbit skins differ from the skins of white hares and European hares in
dense leather, short and elastic fur hair. They differ from the hides of domestic cats in the absence of a mane along the ridge and weak strength properties
of the leather. The quality of the skins depends on the breed of rabbits, as
well as the conditions of their feeding and keeping. Adult rabbits change their
fur twice a year: in spring and autumn.
The leather of rabbit skins vary greatly in thickness. The epidermis is
only 2–3 % of the thickness of the skin, while the dermis is 75–80 %. The papillary layer occupies one third, the rest is the reticular layer. The papillary
layer is penetrated by a large number of hair roots and contains many sebaceous glands. The mesh layer is formed by dense ligature of collagen fiber
bundles intertwined with each other and located mainly in the horizontal direction. The collagen fibers of the dermis are weakly intertwined and laid
parallel to the surface of the skin.
The fur hair is composed of guides, guard, intermediate and downy
hairs. Rabbit skins are widely used for manufacturing various fur products
due to their dense fur hair. These skins are used to imitate a cat, nutria, squirrel, ferret, etc. The number of hairs in 1 thousand pieces per 1 cm
2
ranges
from 13.4 for a nonpedigree animal to 17.0 for a chinchilla. The hair of
44
the rabbit skin is characterized by a strong development of the medulla and
Size
Area, sm2
Extra large
Large
Small
more than 1700
1300–1700
more than 900–1300
the fineness of the cortical layer, which determines the relatively low fastness
to wear of products from rabbit skins.
Preliminary processing. The skin is removed from the carcass with
a tube (removal in a layer is allowed), making an incision around the hock
joints of the hind legs and cutting the skin along the back of the legs through
the anus. Skinning begins with the hind legs. Rabbit skins are processed according to the special rules and preserved by the fresh-dry method.
Rabbit skins are sorted according to GOST 2136-87 and subdivided by
size, grade and group of defects.
By size, fur skins of rabbits of I and II grades are subdivided as follows:
The skins of III grade are not subdivided by size.
Depending on the quality of fur hair and skin, they are subdivided into
three groups. However, the main indicator of the skin grade is the quality of
fur hair (regardless of the season of slaughter of rabbits). In addition, the blue
color of the leather is also taken into account.
According to the defects, rabbit fur skins are divided into three groups.
Batching. Production batches of rabbit skins are selected according to:
– the size (extra large, large, medium, small);
– the skin thickness (with a thickness of up to 0.3; up to 0.5; up to 0.7
and over 0.7 mm);
– the imitation purposes.
When the skins are produced in natural form, the batches are selected
according to the breed (gray giant, black-brown, silver, veil-silver, Viennese
blue, chinchilla, Soviet marder, white giant, butterfly, mongrel); the grades
(highest, first and second grade); the groups of defects (normal, small and
medium defects).
When dyeing skins black for a cat, they are selected according to:
– the skins of pedigree and outbred rabbits of all colors, extra grade
normal, small and medium defect, as well as skins of I grade, normal, small
and partially medium defect;
– the skins of pedigree and outbred rabbit of all colors, second grade
normal and small defect.
,
,
45
When dyeing unshorn skins black, they are selected according to:
– the skins of mongrel and pedigree rabbit of the first and second grades;
– the skins of the third grade.
When dyeing rabbit skins to imitate the skin of nutria, the skins of white
color of the highest and first grades are selected.
The correct choice of a production batch is extremely important for
the quality implementation of technological processes of dressing, dyeing
and finishing. To calculate the batch size, equipment loading rate, as well as
the amount of chemical materials, the average weight of one skin is estimated
(from 125 to 290 g, depending on the size). When dressing rabbit skins,
the production batch usually consists of 3-4 thousand skins.
The skins selected for production batches are sent to the preliminary
processing operations including head trimming and ripping along the midline
of the belly on a DM3-30, shaking and weighing to determine the batch
weight.
Application. Rabbit skins are one of the main types of semi-finished fur
products. They are dyed in a variety of colors. Rabbit skins are divided into
four groups: undyed rabbits, dyed rabbit, fur sheared and dyed rabbit, epilated and dyed rabbit.
The processed skins of a fur rabbit are used in the fur industry both undyed and dyed. Rabbit skins are dyed to imitate the skins of more valuable
animals (fur seal, sable, mink, squirrel, otter, nutria, and polar fox). Light and
beautiful women's coats, children's fur coats, collars, hats and other products
are made from rabbit skins.
The skins should be dressed in a layer while maintaining their configuration and symmetrically straightened. The skins with skin thickness up to
0.5 mm may have a subcutaneous-muscular film on the rump, sides and
belly. Along with undyed and dyed skins, sheared skins (hair height is from
6 to 18 mm), sheared skins with a removed awn are produced.
Sorting. The processed rabbit skins are sorted according to GOST
2974-75. By color, the skins of an undyed rabbit are subdivided into white,
blue, chinchilla, silvery, veil-silvery, black-brown, gray-haired, variegated
and brown; dyed skins are subdivided into black, one-color, multi-colored.
The defects of processed rabbit skins are considered to be seams, bald
patches, holes, worn out places, group notches on shorn skins, deformed and
through hair, awn bite, spinal cord damage on the belly and sides, awn remnants on shorn skins with the awn removed.
Marking. Rabbit skins are marked in accordance with GOST 19878-
2014. In addition, digital symbols of the grade (I – 1, II – 2, III – 3) and
46
the group of defects (first – 1, second – 2, third – 3, fourth – 4) should be applied on the skin surface.
Rabbit skin processing technology. The last Standard technology for
processing rabbit skins was approved in 1992.
When processing rabbit skins, the fleshing process conducted after
soaking is complicated due to the skin weakness. About 40 % of skins is torn
during this process. Enzymatic soaking during fleshing of skins with thickness up to 0.7 mm has a number of advantages in comparison with the use of
surfactants. Enzymatic soaking accelerates and improves the processes of
watering and fleshing. In the case of processing rabbit skins without fleshing,
sodium sulfite is added to the soaking solution along with the enzyme to enhance the effect on the subcutaneous muscle film. The use of enzymatic
soaking in the presence of sodium sulphite without removing the subcutaneous film allows us to obtain uniform penetration of tanning and greasing
agents throughout the entire thickness of the skin.
To reduce the negative effect of sodium sulfite on the strength of hair
fixation, sodium sulfite is added to the solution 6 hours before unloading
the skins (with a total treatment duration of 16–24 hours). The elimination of
the fleshing, unloading, carrying and stacking of skins reduces the cycle time
and complexity of processing. As the number of torn skins decreses, their
yield increases.
Until 1927, according to the standard methods of processing rabbit
skins, the process of tanning was not carried out and the main operation was
picking.
For a better fiber separation of bundles, the process of softening with
enzymatic preparations acting on carbohydrates is carried out. Enzymatic
softening allows us to obtain softer rabbit skins compared to non-enzymatic
methods. Non-enzymatic methods of processing use sulfuric acid or acetic
acid pickling, since softening removes more carbohydrates and non-collagen
proteins than other types of processing.
Before softening, preliminary pickling is carried out using dilute solutions of acetic acid and sodium chloride in order to provide the skin with
the optimal pH value for the action of the enzyme and increase the permeability of the fibrous structure of the dermis. Softening is carried out at a temperature of 38 ºС and the enzyme (for example, maltamamorin P2X) concentration of 1–2 g/dm
3
. Sodium chloride (20 g/dm3) and an antiseptic (1 g/dm3)
are added to the softening solution. The latter inhibits the growth of bacteria
that weaken the action of enzymes. The process lasts for 24 hours.
47
Enzymatic softening is recommended by the Standard technology, since
pre-pickling and softening, as well as further processes (pickling – tanning –
fattening) can be carried out without unloading semi-finished products.
Therefore, we can conduct all processes in one process unit. The softening
solution can be used many times. The use of enzymatic softening is costeffective due to the significant improvement in product quality. In addition,
sheepskins, wool sheepskins, and mink are also softened.
When processing rabbit skins with a skin thickness of more than
0.7 mm, the processes are carried out separately according to the scheme:
pickling – ageing – samming – stickling – tanning – ageing – samming –
stickling – staking – fattening.
Rabbit skins with defects are sorted in separate batches. They may account for up to 5 % of the total number of skins. For such skins, additional
soaking is provided. Typically, it is carried out in a tank or bath.
Skins with a thickness of more than 0.7 mm are drummed before soaking. The process is carried out in sawdust mixed with water and a wetting
agent for 4–6 hours. The wettinf agent is Tetrapol (Baron) SAF. The bath
contains 50 kg of raw materials, 50 kg of sawdust, 10–20 dm
3
2 dm
of Tetrapol. Then the process of shakinis performed for 30 minutes.
3
of water, and
The temperature for soaking is reduced to 25 ºС.
Russian Research Institute of Fur Industry has developed the following
scheme for processing rabbit skins. All processes in liquid solutions are carried out at the float rate 15. The first process is soaking. The process is conducted at a temperature of 25–30 ºС for 12–16 hours. The composition of
the bath is: sodium chloride (20.0 g/dm
FH (0.5 g/dm
out and sent for degreasing at 38 ºС for 3 hours. Deareasing solution contains: Lanem (2.0 g/dm
3
); Effect M (1.0 g/dm3). Then, the raw materials is squeezed
3
); Anticolor B (4.0 g/dm3). After draining and wash-
3
); Gamma 1 (2.0 g/dm3); Preparation
ing, unsealing the legs, fleshing, and sorting are carried out. After that,
the skins are soaked again at 25–30 ºС for 12–14 hours. The composition of
the bath is: sodium chloride (20.0 g/dm
3
); Gamma 1 (1.0 g/dm3). Then,
the solution is drained out and the skins go to the dressing process.
Pickling is carried out at 35 ºС for 16–18 hours. The composition of
the bath is: sodium chloride (50.0 g/dm
Mehsinol (2.0 g/dm
3
); formic acid (8.0 g/dm3). At the end of pickling, the op-
3
); Gamma 2 (1.0 g/dm3);
eration of ageing (12-48 hours), samming, drumming, staking and stickling
are carried out.
Tanning is carried out at 35 ºС for 16–20 hours. The composition of
the bath is: sodium chloride (50.0 g/dm
3
); Gamma 3 (0.5–1.0 g/dm3);
48
Mexinol (2.0 g/dm3). After 1 hour, chrome tanning agent is added (5.0–
6.0 g/dm3); after 2 hours, sodium bicarbonate is added (1.5–2.0 g/dm3). Sodium bicarbonate is added in two steps to pH 3.8–3.9. After 2 hours, aluminum-potassium alum is added (20.0 g/dm3).
At the end of tanning, the semi-finished product goes to ageing (24–
72 hours). Then, the operations of samming, drumming, staking, stickling,
and greasing are carried out.
The semi-finished product is greased by brushing Mexinol
(400.0 g/dm3). The consumption of emulsion for a skin is 20–40 cm3. After
that, the skins are sent to ageing for 2–4 hours. Further processing is carried
out according to the current technology before the drumming process.
The process of drumming is carried out by Gamma 7 (7.0 g/skin) for
3.0–3.5 hours. This is followed by shaking and stacking. Then, drumming is
carried out again for 2.5 hours in the presence of Gamma 7 (5.0 g/skin) and
Antistatic M (2.0 g/skin).
Further processing is carried out according to the current technology.
Aluminum processing of rabbit skins. Pulkra (Boehme) has developed
a technology for processing rabbit skins using aluminum and chromium compounds at the tanning stage.
The skins are sent to the stage of soaking. Process parameters: temperature – 25 ºС, float rate – 15, duration – 16–18 hours. Sodium chloride
(10.0 g/dm3), Atezan LPV (2.0 g/dm3), Foryl PC / EDS (1.0 g/dm3), and 30 %
formalin (0.2 g/dm3) are added to water. Then, the raw materials are sammed
and sent to fleshing.
This is followed by rinsing and degreasing. Degreasing is carried out at
a float rate of 15 and a temperature of 35 ºС for 60–90 minutes. The composition of the bath is: Foryl PC / EDS (2.0 g/dm3); Coratil BLN (1.0 g/dm3);
sodium carbonate (1.0 g/dm3). Then, the process of samming is carried out.
After that, the skins are sent to the dressing operations.
The pickling process is carried out at a float rate of 15 and at a temperature of 35 ºС. 60.0 g/dm3 of sodium chloride is added to the water. After
60 minutes, 3.0 g/dm3 of Pellan GLS is added. After 60 minutes, 10.0 g/dm3
of 85 % formic acid is added. Finally, after 30 minutes, 3.0 g/dm3 of Tannit
AGS is added to the solution. pH at the end of the pickling process is 2.6.
The process takes 14–16 hours. At the end of the process, the skins are ageing
for 12 hours.
Tanning is carried out at a float rate of 15 and at a temperature of 35 ºС.
40.0 g/dm3 of sodium chloride is added to the tanning bath. After 10 minutes
0.5 g/dm3 of 85 % formic acid (pH 3.2–3.3) is added. After 15 minutes,
49
6.0 g/dm3 of Tannit AGS is dosed. After 30 minute, 2.0 g/dm3 of Tannit VGS
is added. After 60 minutes, 3.0 g/dm
30 minutes, 1.0 g/dm
3
of sodium bicarbonate is added to the solution.
3
of Pellan GLS is added. After
The process duration is 16–18 hours; pH at the end of the process is 3.6.
Next, the semi-finished product is sammed and sent to trimming on
a disc knife. Brushing greasing is carried out at a temperature of 35 ºС in
the presence of Pellan FSN (1:3). Then, the process of drying is carried out.
Then, the process of wet drumming ids carried out Kutafix LGF and water
for 100 kg of sawdust for 120 minutes. Next, the semi-finished product is
shaken, stacked and drummed.
Dry drumming is carried out for 240 minutes in 1.0–1.5 dm
LGF, 1.0 dm
3
of Softymol CPH per 100 kg of sawdust. After that, the semi-
3
of Kutafix
finished product is shaken, stacked and sent to further processes and finishing operations.
Chrome prosessing of rabbit skins. The skins are sent to the stage of
soaking. Process parameters: temperature – 25 ºС, float rate – 15, duration –
16–18 hours. 10.0 g/dm
1.0 g/dm
3
of Foryl PK / EDS, 0.2 g/dm3 of 30 % formalin are added to the
3
of sodium chloride, 2.0 g/dm3 of Atezan LPV,
water. The skins are not unloaded until morning. Then the raw materials are
sammed and sent to the stage of fleshing.
Then, the operations of rinsing and degreasing are carried out. Degreasing is carried out at a float rate of 15 and at a temperature of 35 ºС for 60–
90 minutes. 2.0 g/dm
3
of Foryl PK / EDS and 1 g/dm3 of sodium carbonate
are added into water. After that, the skins are sammed and sent to the stage
of pickling.
The process of pickling is carried out at a float rate of 15 and at a temperature of 35 ºС for 16–18 hours. 60.0 g/dm
the water. After 60 minutes, 3.0 g/dm
60 minutes, 10.0 g/dm
30 minutes, 3.0 g/dm
3
of 85% formic acid is added. Finally, after
3
of Tannit AGS is added. pH at the end of the pickling
3
of sodium chloride is added to
3
of Pellan GLS is added. After
process is 2.6. Then, the skins are ageing for 12 hours.
The process of tanning is carried out at a float rate of 15 and at a temperature of 35 ºС for 16–18 hours. 40.0 g/dm
the solution. After 10 minutes, 0.5 g/dm
is dosed. After 15 minutes, 3.0 g/dm
30 minutes, 1.5 g/dm
3
of Tannite HC is added. After 30 minutes 5.0 g/dm3
of chromium salt with a basicity of 33 % is added. After 30 minutes, the second portion of chromium salt (5.0 g/dm
3.0 g/dm
3
of Pellan GLS is added. After 60 minutes, 1.0 g/dm3 of sodium
3
of sodium chloride is added to
3
of 85 % formic acid (pH 3.2–3.3)
3
of Tannit AG is dosed. After
3
) is added. After 90 minutes,
50
bicarbonate is added to the solution. The skins are not unloaded until morning; pH at the end of the process is 3.8.
Then, the operations of rinsing are carried out at a float rate of 15, a temperature of 35 ºС for 15 minutes. 0.5 g/dm3 of Foryl PK / EDS and 0.5 g/dm3
of 60 % acetic acid are dosed into the water. The value of pH at the end of
the process is 3.9. After rinsing, the skins are sammed and sent to the stage
of stacking using a disc knife.
The next stage of brushing greasing is carried out at a temperature of
35 ºС in the presence of Pellan FSN (1:3). Next stage is drying, followed by
wet drumming. The operation of drumming is carried out for 120 minutes in
3.0 dm3 of Kutafix LGF and water for 100 kg of sawdust. After that, the
semi-finished product is shaken and stacked.
Dry drumming is carried out for 240 minutes in 1.0–1.5 dm3 of Kutafix
LGF and 1.0 dm3 of Softymol CPH per 100 kg of sawdust. After that,
the semi-finished product is shaken, stacked and sent for further finishing
operations.
Lowenstein has developed a chrome-alumina tanning technology for
rabbit skins with fatliquoring in a tanning bath.
First, the skins should be cut. The heads and tails are trimmed. Then the
skins go to soaking, which is carried out at 30 ºС for 24 hours. 25.0 g of sodium
chloride, 1 cm3 of Wetter HAC, and 1.5 g of Elbro 100-C are added to 1 dm3
of water. After soaking, the operation of fleshing is carried out.
Then, the operation of washing (only for oily skins) is carried out at 32 °C
for 30 minutes. 2.0 g of De-Sol-A and 1.0 g of sodium carbonate are added to
1 dm3. The bath is rotated for 10 minutes, then it stops for 15 minutes and
roates again for 5 minutes. Then, the solution is drained out.After that, rinsing
is carried out with clean water at a temperature of 32 ºС for 10 minutes.
The operation of pickling is carried out at 32 ºС for 16–18 hours. 50.0 g
of sodium chloride, 2 cm3 of Super Lotana A, 2 cm3 of formic acid are dosed
into 1 dm3. The bath is rotated for 15 minutes and then stops overnight. After that, the skins are sammed and sent to stickling (for heavy skins).
The next process is tanning. It is carried out at a temperature of 32 ºС
for 16–18 hours. 60.0 g of sodium chloride, 40.0 g of aluminum alum, 5 cm3
of 40 % formalin, 1 cm3 of El-Cro-Tan, 5 cm3 of Tanning Oil G, 1 cm3 of
Liquid Brightener C (only for white skins) are added to 1 dm3 of water.
The bath is rotated for half an hour and then stops overnight. Then, the semifinished product is sammed.
The next operation is drumming. It is carried out after complete drying
in clean sawdust for half an hour, until the hair is free from excess fat. Then,
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