Transcript
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WELCOME TO MY WELCOME TO MY PROJECT WORKPROJECT WORK

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Title:Title: STUDIES ON THE STUDIES ON THE PRODUCTION OF CRACKLE PRODUCTION OF CRACKLE

FINISH LEATHER FROM COW FINISH LEATHER FROM COW HIDEHIDE

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ACKNOWLEDGEMENTACKNOWLEDGEMENT

Man is the greatest creature of ALLAH. So I at first take the name of Man is the greatest creature of ALLAH. So I at first take the name of omnipotent ALLAH who has created me as a man and whose omnipotent ALLAH who has created me as a man and whose blessing directed me towards the accomplishment of this project blessing directed me towards the accomplishment of this project work. I also express my deepest respect to Institute Of Leather work. I also express my deepest respect to Institute Of Leather Engineering And Technology where I passed my several years of Engineering And Technology where I passed my several years of life.life.

I would like to express my deepest sense of gratitude and sincere I would like to express my deepest sense of gratitude and sincere appreciation to my respectable teacher and also to Professor Dr. appreciation to my respectable teacher and also to Professor Dr. Md. Idris Ali principal of Institute of Leather Engineering and Md. Idris Ali principal of Institute of Leather Engineering and Technology, Mr. Sobur Ahmed (Assistant Professor) Head of the Technology, Mr. Sobur Ahmed (Assistant Professor) Head of the Leather Engineering Department and thesis supervisor Md. Hanif Ali Leather Engineering Department and thesis supervisor Md. Hanif Ali (from whom I got instructions to finish this project work).(from whom I got instructions to finish this project work).

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I like to extend my heartily thanks to Mr. Abid Siddiquee who always I like to extend my heartily thanks to Mr. Abid Siddiquee who always helped me to finish the leather by giving practical help and technical helped me to finish the leather by giving practical help and technical information about different chemicals which should be used and information about different chemicals which should be used and which should not.which should not.

Finally, I owe a great homage to other teachers who are the assets Finally, I owe a great homage to other teachers who are the assets of this institute, thanks to the Librarian, all the stuffs of C.F.F.C. and of this institute, thanks to the Librarian, all the stuffs of C.F.F.C. and other laboratories who directly or indirectly helped me to complete other laboratories who directly or indirectly helped me to complete this project workthis project work

Sadman ProdhanSadman Prodhan

April, 2012April, 2012

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THE AIM OF THE PROJECT THE AIM OF THE PROJECT WORKWORK

The original purpose of this project work is the production of Crackle The original purpose of this project work is the production of Crackle finished leather.finished leather.

In the production of leather there are always some low quality raw hides In the production of leather there are always some low quality raw hides

and skins. These hides when tanned produces lower grade leather. This and skins. These hides when tanned produces lower grade leather. This lower grade leather never gets enough prices from the buyers. So providing lower grade leather never gets enough prices from the buyers. So providing a proper special effect may increase the value of these hides and skins.a proper special effect may increase the value of these hides and skins.

Split leathers are by product of the tanning industry. Due to quality and Split leathers are by product of the tanning industry. Due to quality and

fashion the quantity of splits produced often does not fulfill customer fashion the quantity of splits produced often does not fulfill customer demand. So there has been much experimental work to convert a split into a demand. So there has been much experimental work to convert a split into a product that looks and behaves like grain leather.product that looks and behaves like grain leather.

So I have decided to do this research work on the production of crackle So I have decided to do this research work on the production of crackle finished leather.finished leather.

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WHAT IS CRACKLE FINISH?WHAT IS CRACKLE FINISH?

Crackle is an interesting finish that gives the appearance of age on the Crackle is an interesting finish that gives the appearance of age on the surface of painted pieces. This finish is done by a commercial product and surface of painted pieces. This finish is done by a commercial product and requires two colors of pigment - one for the undertones and the other for requires two colors of pigment - one for the undertones and the other for the top.the top.

The crackle finish includes a base coat of latex paint that is applied on a The crackle finish includes a base coat of latex paint that is applied on a surface. A crackle coating is applied over the base coat and dried to tack surface. A crackle coating is applied over the base coat and dried to tack dry or completely dried, latex wood filler is applied over the crackle dry or completely dried, latex wood filler is applied over the crackle medium. As the latex wood filler dries, it forms islands or domains medium. As the latex wood filler dries, it forms islands or domains separated by cracks or valleys revealing glimpses of the underlying base separated by cracks or valleys revealing glimpses of the underlying base coat.coat.

A crackle glaze or varnish is a finish which creates a crackled effect. Many A crackle glaze or varnish is a finish which creates a crackled effect. Many people use crackle glazes for antiquing, because peeling, crackled paint has people use crackle glazes for antiquing, because peeling, crackled paint has an old-fashioned look which goes especially well with restored furniture. an old-fashioned look which goes especially well with restored furniture. Crackle g1azes can be used on a wide range of things including pottery, Crackle g1azes can be used on a wide range of things including pottery, furniture- picture frames, and even walls, a number of craft stores sell furniture- picture frames, and even walls, a number of craft stores sell materials for crackle glazing, and we can also accomplish the effect with a materials for crackle glazing, and we can also accomplish the effect with a few supplies we probably already have around the house.few supplies we probably already have around the house.

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When a crackle glare is made, one color is laid down as a base coat When a crackle glare is made, one color is laid down as a base coat and allowed to dry before a crackling medium is painted over it. and allowed to dry before a crackling medium is painted over it. Once this medium dries, another coat of color is applied and cracks Once this medium dries, another coat of color is applied and cracks and peels start to appear almost immediately. To seal a crackle we and peels start to appear almost immediately. To seal a crackle we place a clear varnish or polyurethane sealer can be used. This place a clear varnish or polyurethane sealer can be used. This sealer also halts the crackling process so that the second layer of sealer also halts the crackling process so that the second layer of color doesn't flake off entirely. color doesn't flake off entirely.

Since the underlying color shows through, many people try to use Since the underlying color shows through, many people try to use coordinating colors when they apply a crackle glaze. Contrasting coordinating colors when they apply a crackle glaze. Contrasting colors can also work quite nicely, like a dark under layer and a lighter colors can also work quite nicely, like a dark under layer and a lighter over-layer. If we aren't sure about how two colors will look together, over-layer. If we aren't sure about how two colors will look together, we can test them on a small area of the piece to make sure that they we can test them on a small area of the piece to make sure that they look goodlook good

Once they dry, we can also use a medium like gold, silver, or copper Once they dry, we can also use a medium like gold, silver, or copper paint for one of the layers for a richer look. paint for one of the layers for a richer look.

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If we cannot track down a crackling medium, we can also use white If we cannot track down a crackling medium, we can also use white glue. White glue acts as a layer of resist, preventing the second layer glue. White glue acts as a layer of resist, preventing the second layer of paint from fully adhering. This will create a more mottled effect; we of paint from fully adhering. This will create a more mottled effect; we can also use wax as a resist for a crackle finish. If we are working can also use wax as a resist for a crackle finish. If we are working with pottery, we use a glaze which has been designed to crack, and with pottery, we use a glaze which has been designed to crack, and follow the directions closely.follow the directions closely.

The crackle glaze effect is sometimes called craqueleure and in fine The crackle glaze effect is sometimes called craqueleure and in fine art it is sometimes used as a tool to date artworks and establish their art it is sometimes used as a tool to date artworks and establish their provenance. Forgers spend lifetimes mastering the art of a properly provenance. Forgers spend lifetimes mastering the art of a properly crackled final layer of paint in the hopes that their works will pass crackled final layer of paint in the hopes that their works will pass muster by art inspectors: a dedicated forger may infuse a craqueleure muster by art inspectors: a dedicated forger may infuse a craqueleure with dust and particulates from an old piece of art from the right with dust and particulates from an old piece of art from the right region in case an art inspector decides to chemically analyze the region in case an art inspector decides to chemically analyze the finish.finish.

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Objects of Crackle finish:Objects of Crackle finish:

To make a fashionable article.To make a fashionable article. To enrich physical outlook of lower grade leather.To enrich physical outlook of lower grade leather. To recover the faults on leather surface, Crackle finish is useful and To recover the faults on leather surface, Crackle finish is useful and

effective.effective. To upgrade glossy property.To upgrade glossy property. The maximum utilization of leather byproduct (e.g. split) is ensured by The maximum utilization of leather byproduct (e.g. split) is ensured by

crackle finish.crackle finish. Improve the water resistance of the leather. I.e. the finish should not Improve the water resistance of the leather. I.e. the finish should not

discolor or swell and hence protect the leather and retain its good discolor or swell and hence protect the leather and retain its good appearance.appearance.

Render the leather light fast.Render the leather light fast. Render the leather heat fast.Render the leather heat fast. Render the leather fast to alkalis.Render the leather fast to alkalis. Render the leather fast to acids.Render the leather fast to acids.

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Procedure of Crackle FinishProcedure of Crackle Finish We use Acrylic paint of two colors, one for the top color and another for We use Acrylic paint of two colors, one for the top color and another for

the base color that will show through the cracks. This can be any the base color that will show through the cracks. This can be any combination, but a dark and light contrast works well.combination, but a dark and light contrast works well.

Let us apply the base coat of desired acrylic paint. Let dry.Let us apply the base coat of desired acrylic paint. Let dry. Spray or roller coat one coat of crackle glaze over base coat. Let dry for Spray or roller coat one coat of crackle glaze over base coat. Let dry for

20 minutes to one hour.20 minutes to one hour. Brush on the top color of acrylic. The moisture of the top coat of paint Brush on the top color of acrylic. The moisture of the top coat of paint

will instantly activate the glaze, and the top coat will crackle. The wetter will instantly activate the glaze, and the top coat will crackle. The wetter the top coat the more crackle. the top coat the more crackle.

We make a sample of different color combinations for future reference. We make a sample of different color combinations for future reference. Try adding some water to the top coat of acrylic to see the difference in Try adding some water to the top coat of acrylic to see the difference in crackling.crackling.

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NoteNote

Success of crackle finish mostly depends on the drying of film after Success of crackle finish mostly depends on the drying of film after finishing coat. Here in sample (1) I dried the film in open air while in finishing coat. Here in sample (1) I dried the film in open air while in sample (2) I used the dryer to dry the finish coat quickly. As a result, sample (2) I used the dryer to dry the finish coat quickly. As a result, it is evident that the first sample consists of small crackles while the it is evident that the first sample consists of small crackles while the other one got larger crackles. other one got larger crackles.

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PHYSICAL TESTPHYSICAL TESTData for tensile strength, elongation at break Data for tensile strength, elongation at break

Tensile strength Tensile strength

sample vertical Horizontal

Tensile strength In unit (N)

Elongation at break in(%)

Tensile strength In unit (N)

Elongation at break in (%)

1 230 49 254 52

2 198 43 210 49

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Data for stitch tearing strengthData for stitch tearing strength

Sample No Thickness (mm)

Tearing load (kg)

Stitch tearing strength (kg/cm)

1 2

1.21.1

2220

183.3181.8

Standard for shoe upper: Stitch tear strength = Min. 60-120 kg/cm

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Data For Tearing StrengthData For Tearing Strength

Sample-1Sample-1

Perpendicular- 45.45 Kg/cmPerpendicular- 45.45 Kg/cm

Parallel- 54.54 Kg/cmParallel- 54.54 Kg/cm

Sample- 2Sample- 2

Perpendicular- 40.90 Kg/cmPerpendicular- 40.90 Kg/cm

Parallel- 50.00 Kg/cmParallel- 50.00 Kg/cm

Standard Value- 40 Kg/cmStandard Value- 40 Kg/cm

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Data for dry and wet rub fastnessData for dry and wet rub fastness

Dry rub fastness (grey scale reading) Wet rub fastness (grey scale reading)

sample 64 rev.

128 rev.

256 rev.

612 rev.

1024 rev.

16 rev.

32 rev.

64 rev.

128 rev.

256 rev.

1 5 5 5 5 4 5 5 4 4 4

2 5 5 5 4 4 4 4 4 3 3

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CHEMICAL TESTCHEMICAL TESTDATA FOR CHROMIC OXIDE CONTENT DETERMINATIONDATA FOR CHROMIC OXIDE CONTENT DETERMINATION

Sample No % Of Chromic oxide content

1 2

Standard value 2.5-4.0%

3.5% 2.9%

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DATA FOR ASH CONTENT DETERMINATIONDATA FOR ASH CONTENT DETERMINATION

Sample No % Of Ash content

1 2

Standard value 2.0%

2.8% 2.3%

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SamplesSamples

sample 1 sample 2sample 1 sample 2

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CONCLUSIONCONCLUSION

Crackle finish is a finishing effect that easily attracts any buyer. So it Crackle finish is a finishing effect that easily attracts any buyer. So it can be widely used in leather industry with profitable aspect. can be widely used in leather industry with profitable aspect.

On the other hand, Split leathers are byproducts of the tanning On the other hand, Split leathers are byproducts of the tanning industry. Normally the Splits produced are often used to industry. Normally the Splits produced are often used to manufacture suede. Due to quality and fashion the quantity of splits manufacture suede. Due to quality and fashion the quantity of splits produced often exceeds customer demand and there has been produced often exceeds customer demand and there has been much experimental work to convert a split into as good as a original much experimental work to convert a split into as good as a original grain leather.grain leather.

But in our country, there is less room and limited machineries to But in our country, there is less room and limited machineries to control the quality of these leather.control the quality of these leather.

I hope necessary steps would be taken which will help to occupy the I hope necessary steps would be taken which will help to occupy the domestic and international market.domestic and international market.

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Thanks For Your Thanks For Your Patience.Patience.


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