Practical tanning; a handbook of modern processes, receipts, and suggestions for the treatment of hides, skins and pelts of every description, including various patents relating to tanning, with specifications

Front matter

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Kx>;r —

Preface To The Second Edition

In presenting to the Leather Industry and to the dealers in, and the consumers and inspectors of, hides, skins, pelts and leather, as well as to the dyers of leather, this new, revised, enlarged, and systematically arranged edition of his Practical Tanning, the author has this to say, for himself and for his book :

Like its predecessor, this volume embraces the results of his own experience, his study and research, and the experiences of the many practical men with whom it has been his good fortune to come into association and consultation ; and the book has been so carefully and thoroughly revised throughout, as practically to be considered as having been rewritten. Nothing whatever has been incorporated into it that has previously appeared in any American or English book — his own alone excepted — and it is intended to present the newest and best American practice of this now great and progressive industry. He has diligently consulted the leading American trade papers and v/here it has been found possible, in the text, given due credit; but he would here acknowledge his special obligations to The Shoe and Leather Reporter.

This volume is, as its title implies, essentially a practical treatise, and the details of that practice are given with such clearness and precision, such absence of confusing technicalities, as is believed to demand nothing more . As a typical illustration of this thoroughness , the author would refer to the section devoted to Sheepskins. There will be found complete directions for handling these skins from the time they are received by the tanner or the wool-puller until they are turned out as finished leather.

In the Appendix will be found descriptions of various processes of tanning, unhairing, coloring and finishing skins and leather that have been recently patented by their inventors. These processes are given, not with the idea of advertising or recommending them, but rather to enable the reader to learn of processes that are a little out of the ordinary practice ; in which new materials are used or old ones employed vi PREFACE TO THE SECOND EDITION.

in new ways. Some of these processes[^are undoubtedly of value, while the value of others may bejquestioned. However, to read them, one and all, will, it is believed, add to the tanner's knowledge of his art.

The first edition of Practical Tanning having been received by the trade with such distinct favor ,^as"weirabroad as at home, it is believed that this one, so great an advance in value over its predecessor, must also prove a further help to the tanner, and a marked success generally.

In conclusion he would state that the volume has been supplied with such a full table of contents, and such an exhaustive index as to render references to any subject or detail in it prompt, easy and satisfactory.

L. A. F.

SECTION ONE. The Manttpactuee oe Side Leather

PAGE

Soaking green-salted hides; Most approved method of soaking; Object of the

soaking process. ...... .... 1

Effect of too long soaking on salted hides; Water for soaking; Softening hard

water; Effects of careless soaking ........ 2

Soaking dry hides; Unhairing sun-dried hides 3

Methods of liming; Liming for upper leather; Starting the liming process . 4

Washing the unhaired hides and after-treatment; Quantity of lime required . 5

Sulphide of sodium process .......... 6

Methods of bating; Bating with lactic acid ....... 7

Bating with a bacterial bate ... "...... 9

Commercial bates; Bating with chicken manure . . . . . .10

The piclding process; Pickling with sulphuric acid and salt . . . .11

Methods of splitting; Splitting out of lime . • 12

Splitting out of sulphate of alumina and salt pickle; Splitting after tanning;

Splitting out of acid pickle ......... 13

Processes of chrome tanning for side leather; Process for acid-pickled grains . 14

One-bath process for acid-pickled grains ....... 15

Process for alumina-pickled grains; Processes for unsplit sides . . .16 Mode of ascertaining when the hides are tanned; Eetanning; Washing and

' Practical methods of coloring chrome upper leather; Dyeing with natural dyestufls; Light tan; Dark tan . . . . . . . . .18

Ox-blood; Chocolate brown; Alizarine red-brown ...... 19

Alizarine brown ; Mordant for aniline colors ....... 20

Palmetto mordant; Peachwood-fustic mordant ...... 21

Gambler mordant; Use of tartar emetic. ....... 22

Dissolving aniline dyes; Titanium mordants ....... 23

Dyeing chrome side leather black; With logwood and bichromate of potash, 24 With logwood and titanium salts; With logwood and copperas; AVith logwood and nigrosine ........... 25

Fat-liquors for chrome side leather; Process of fat-liquoring . . . .26

Receipts for fat-liquors for colored or black leather and for chrome side

(vii)

Vlll CONTENTS.

PAGE

Tat-liquors for heavy English or storm grain leather, for colored leather, for grained chrome leather, either black or grained, and for colored or black

grain 28

Fat-liquors for dull finished leather, for leather colored with basic aniline colors, and for heavy grain chrome leather ...... 29

Fat-liquors for soft leather, colored or black, for chrome side leather, and for smooth glazed, boarded and dull finished leather . . . . .30

Finishing chrome side leather .... .... 31

Dull finish; Glazed finish; Boarded finish ....... 32

Finishes for chrome side leather; For glazed and bright boarded finish; Dull

.finish 33

Gun-metal finish; For oil or storm-grain leather; Another finish for heavy grain leather ............ 34

Finish for colored leather; Chrome side glove and mitten leather; Coloring for grain finish . . . . . . . . . . . .35

Mode of producing light and darker tan colors and a yellow shade; Fat-liquor receipt ............ 36

Finishing; Chrome bag and belt leather ....... 37

White side leather; Tanning with sulphate of alumina; Pickling; Preparation of the tan liquor .......... 38

Fat-liquoring with acid fat-liquor; Finishing . . ... . .39

White chrome leather; Treatment with flour; Preparation of a suitable fat-liquor; Finishing ........... 40

Another mode of preparing good white leather; Chrome side patent leather; Pickling and tanning .......... 41

Coloring and fat-liquoring . . . . . . . . . . 42

Staking and finishing ........... 43

Vegetable tanning processes for side leather; Material used for this purpose; Process of tanning; Tanning with hemlock and quebracho extracts . . 44

Tanning with quebracho and palmetto extracts 45

Tanning with palmetto extract ......... 46

Tanning with gambler; Combination process of tanning 47

Pressing and splitting; Ketanning processes ....... 48

Retanning with gambler and sumac; Eetannage for hemlock-tanned leather . 49 Retanning with palmetto extract, and in combination with quebracho; Addition of bisulphide of soda to the retanning liquor; Clearing the grain with alum and salt ............ 50

Coloring and finishing vegetable-tanned upper leather; Outline of the process; Application of fat-liquor .......... 51

Manner of handling all kinds of combination-tanned sides . . . .52

Fat-liquoring leather; Fat-liquor formulas ....... 53

Stuffing for imitation kangaroo and dull printed sides; Fat-liquor for hemlock-quebracho and quebracho-palmetto tanned leather . . . . .54

Fat-liquor for bright printed or boarded grains; Eeceipts for yellow flesh; Receipts for blue flesh . . . . . . . . . . .55

Finish for bright boarded grain leather 56

CONTENTS. ix

PAGE

Finishing bark-tanned kanguroo side leather. . . . . . .57

Preparation of a sig to be used on kangaroo sides, of a logwood liquor, and of

a black or striker; Coloring side leather ....... 58

Fat-liquor for colored Russia leather ; Process of preparing the sides for

Russia leather with sumac. ......... 59

Vegetable-tanned patent shoe tipping; Requirements of good strong tipping;

Tanning tipping hides .......... 60

Another retanning process ......... 61

Preparation of the retan liquor, and of the fat-liquor; Manufacture of bag

and case leather ........... 62

Bating; Pickling; Tanning .......... 64

Clearing and bleaching the grain ; Usual practice of bleaching leather . . 65 Bleaching and coloring; Finishing rough leather ...... 66

Preparation of the acid bath ......... 67

Finishing; Receipt for waterproof linish for colored bag and case leather;

Finish for colored and russet leather ........ 68

Seasoning which gives a nice black luster that is lasting; Finishing imperfect

grains into patent tipping; Retanning . . . ' . . . .69

Fat-liquoring; Manufacture of Goodyear welting; Hides from which the best

welting is made; Tannage suitable for welting ...... 70

Bleaching to remove stains; Materials largely used as welting and their

How to prepare hides for tanning into lace leather; Hides for lace leather;

Preparation of the hides; Pickling ........ 72

Tanning; Yellow lace leather; Method of making leather especially suitable

for belt, shoe and leather laces . . . . ". . . . .73

Another way to tan the leather ......... 75

Fat-liquor for lace leather; Oiling and iinishing . . . . . .76

Alum-tanned lace leather .......... 77

Dubbing used to stuff the leather and mode of stuffing . . . . .78

Old method of making lace leather; Preparation of lace leather that is soft

Another composition for lace and whip leather; Stuffing alum- tanned hides,

dried and moistened ........... 80

Raw hide lace leather; Preparation of the tanning liquor; Another process . 81 Other methods of making lace leather; Tawed lace leather . . . .82

Picker leather; Liming .......... 83

Stuffing; Tanning and finishing splits; Source of splits . . . . .85

Retanning rough splits; Working splits into Goodyear; Softening and stuffing heavy splits ........... 87

Stuffing for wax splits; Finish for the back . . . . . . .88

Soap black; Flour paste 89

Finishing splits into Goodyears, chair splits, etc. ...... 90

X CONTENTS.

SECTION TWO. The Manufacture or Sheepskin Leather

Soaking sheep pelts; Methods of removing the wool

Formulas for depilatory liquors ....

Liming after removal of the wool; Sulphide of sodium process . . .95

. 96 . 97

93 94 for chrome tanning . 99

. 100

. 101

. 102

for this purpose . . 10.3

Methods of drenching sheepskins .

Another method; Drenching with bran .

Pickling with sulphuric acid and salt .

Pressing the grease from pickled sheepskins; Processes

Tanning with sulphate of alumina and chrome liquor

FoiTuula for preliminary tawing ....

Manner of tanning pickled sheepskins .

Dyeing chrome-tanned sheepskins black, and formulas

Process of giving the skins a tannin mordant, and coloring the flesh sides blue

and the grain sides black . . . . . . . . . .104

Dyeing black and refinishing sheepskins that have been colored and finished;

Fat-liquore for chrome-tanned sheep and lambskin leather. . . . lO-'i

Methods of coloring chrome-tanned sheepskins; Mordant for aniline dyes;

Tanning material most commonly used in dyeing sheepskins; Tan colors on

Chocolate-brown on sheepskins 109

Brown on sheepskins; Anilines valuable in dyeing chrome-tanned skins. . 110 Ox-blood or wine color on sheepskins . . . . . . . .111

Dye for shoe and glove leather; Brown on shoe and glove leather . . .112

Green on chrome sheep leather 113

Yellow glove and mitten leather, and formulas for the purpose; Coloring

chi'ome-tanned sheepskins after fat-liquoring; Preparation of the mordant;

Formula for coloring 114

Finishing black-glazed sheepskins; Clearing the grain; Formula for seasoning. 115

Formulas for seasonings for glazed finish 116

Good way to clear the grain of greasy matter; Seasoning for dull finish; Finishing colored sheepskins; Formulas for seasonings . . . . .117 Good seasoning for black glazed sheepskins; Glazed finish on colored sheepskins. 118 Finishing sheepskin glove 'leather and various methods for the purpose. . 119

Flesh-finished chrome sheepskins; Skins used for the pui'pose; Tanning the

skins 120

Treatment after tanning; Coloring and fat-liquoring 121

Drenching and pickling sheepskins with formic acid ; Mixture of formic and

lactic acids; Bran di-enching 122

Mode of pickling; Pickling with acetic acid . . . . . . .123

Sheepskins for jacket leather; Pressing to remove the grease; Tanning the

Coloring and finishing; Formula for the finish; White sheep leather . . 125

Preparation of the tanning liquor 126

Sulphated oil or acid fat-liquor, and its use; Tanmng with alum and salt . 127

CONTENTS. XI

PAGE

Preparation of a tanning solution; Another way to tan with alum and salt . 128 ^^^nother good way of tanning sheep and lambskins . . . . .129

White chrome-tanned sheep leather; Pickling sheep and lambskins . . 130 Tanning white sheep leather; Bleaching liquor ...... 131

Treatment with flour; Fat-liquors for these skins 132

Finishing chrome-tanned skins; White Napa leather, and modes of tanning it. 133 Original process of tanning white Napa leather ...... 134

Tanning with alum, sumac and oak bark; Preparation of the tanning liquor. 135 Coloring black Napa leather; Use of direct blue paste for coloring the flesh

side blue; Preparation of a good sig ........ 136

Coloring alum-tanned leather; Preparation of a so-called nourishment . . 137

Washing the skins for coloring; Chamois leather, and its production . . 138 Oiling and beating the skins; Finishing processes . . . . .139

Various methods of treating the skins . . . . . . . .140

Coloring chamois skins, and a practical method for the purpose . . .141

Bleaching chamois skins; Removal of the excess of oil; Prepar? an of the

bleaching liquor ........... 142

Preparation of sulphurous acid; Sheepskin-fleshers, and mode of tanning them. 143

Tanning with basic alumina liquor; Fat-liquoring 144

Tanning with ahmi, salt, egg-yolk, and flour; Chrome-tanned fleshere . . 145 A process for sheepskin fleshers to be used in the manufacture of gloves, for

Vegetable-tanned sheepskins; Hemlock tannage . Most satisfactory way of tanning ....

Use of oak liquors; Quebracho tannage

Combination tannage .

Modes of tanning .......

Sumac tannage; Sheepskins for upholstering pui-poses;

sheepskins into what is called Spanish leather for furniture and automobiles. 152 Methods of coloring vegetable-tanned sheepskins; Washing and sorting the

skins; Good way to color the skins; Use of titanium-potassium oxalate in

leather coloring . . . . . . . . . . .154

Ih^eing the skins black . . . . . . . . . . .155

Method of handling the skins for soft, black leather; Advantage of dyeing

with logwood and titanium salts ........ 156

Coloring with aniline dyes; Ox-blood ........ 157

Oxblood on vegetable-tanned skins; Brown . . . . . . .158

Red; Shades of tan, green, yellow, brown, etc. . . . . . . 159

Treatment for dark greasy skins; Fat-liquoring . . . . . .160

Seasonings for colored skins .......... 161

Finish for embossed sheepskins; Methods of embossing; Skivers . . . 162 Use of skivers; Drenches for the grains ....... 163

Pickling liquor; Materials for tanning skivers and modes of tanning . . 165 Finishing skivere . . . . . . . . . . . .166

Roller leather; Qualities required of roller leather; Tanning the skins . . 167 Tanning woolskins; Soaking, washing and scouring ..... 168

XU CONTENTS.

Tanning; Preparation of tanning paste .

Bleaching; Degreasing .....

Tanning with gambier; Chrome-tanned woolskins

Practical method for this pui"pose ....

Paste for the flesh; Coloring ....

Good shade of tan ; Tanning with alum, salt and hemlock extract

Dyeing woolskins black .......

SECTION THEEE.

The Manufacture of Calf Leathers.

Importance of the beamhouse work; Soaking of green-salted skins for chrome

Benefit derived from the use of borax in the soaks; Danger in using old stale

soaks 180

Soaking dry skins; Importance of keeping the skin-substance intact . . 181 Methods of liming and bating calfskins; Liming in arsenic limes . . . 182 Preparing the skins with lime and sulphide of sodium; Various methods employed in liming ........... 184

New process of liming skins ^. ......... 186

Bating or drenching; Bating with lactic acid; Bating with a fermented lactic

acid bate 187

Fermentative bating with lactic acid . . . . . . . .188

Bating with bran ; Bating with manure . . . . . . . .189

Pickling; Process of chrome-tanning; One-bath process . . . . . 191

One-bath process with sulphate of alumina and sal soda. .... 192

Two-bath process of tanning. . . . . . . . . .193

How to color chrome-tanned calfskins; Preparation of the leather for the reception of aniline dyes; Application of the dyes. . . . . .194

Washing the skins ........... 195

Gambier and fustic mordant; Gambier mordant; Quermos extract mordant . 196 Sumac mordant; Palmetto mordant ........ 197

Clearing the grain and setting the color with tartar emetic; Receipts for oxblood shades ............ 198

Alizarine brown on chrome calfskins; Chocolate brown with dyewoods and aniline dyes ............ 200

Light and dark tan shades; How to dissolve aniline dyes .... 202

Process of coloring after fat-liquoring; How to dye chrome-tanned calfskins black; Dyeing with logwood and titanium salts ...... 203

Dyeing with logwood and bichromate of potash ; Dyeing with logwood and copperas; Dyeing with aniline black ........ 204

Fat-liquors for black and colored chrome-tanned sheepskins .... 205

Oiling and drying the leather ......... 208

Dampening and staking; Glazed finish; Border or box finish .... 209

Smooth dull finish ; Seasoning for glazed finish ...... 210

Gun-metal finish; Sea.soning for chrome-colored calfskins . . . .211

CONTENTS.

xm

Calfskin glove and mitten leather; Sorting and liming the skins; Process of bating .........

Pickling the skins; Two-bath chrome system of tanning.

Tan shades on glove and mitten leather

Light yellow on glove and mitten leather

Chrome wax calf leather; Skins for this purpose; Retanning

Fat-liquoring ........

Blacking; Paste ........

Finish, and its preparation; Vegetable tannages for calfskin upper leather Gambler tannage .......

Dongola leather ........

Tanning with palmetto; Q.uebracho and palmetto tannage; nage .........

Qiiebracho and hemlock extracts tannage; Receipts for fat-, table-tanned calf leather ......

Giving two applications of fat-liquor ....

Sumac mordant for colors ......

Titanium mordant for colors ......

Coloring and finishing of vegetable and combination-tanned calfskins; Preparations for blue and yellow flesh ......... 228

229 230 231 232 233

Quebracho tanliquors for vege-

219 221

223 225 226

Dyeing leather upon the grain, and materials used ....

Receipts for strikers; Dyeing with logwood and titanium salts

Russet and fancy leather calfskins; Preparation of the skins for this object

Bating, and materials employed for this purpose .....

Vegetable tanning processes; Tanning with quebi-acho extract Tanning with hemlock and quebracho exti-acts combined, and with quebracho and palmetto extracts; Fat-liquoring ........ 234

Tat-liquors; Preparation for coloring ........ 235

Black leather 237

Finishing; Bleaching hemlock-tanned skins; Light russet color on leather . 238 Preparation of the bleaching liquor, and of the fustic liquor .... 239 Dark msset color on leather .......... 240

SECTION FOUR. The C^oiiOKiNG ajstd Tanning of India-tanned Skins

Use of India-tanned skins; Washing the skins ...... 241

Importance of thorough washing ......... 242

Coloring the skins ........... 243

Dyeing the skins black ........... 244

Black glazed finish; Receipts for seasoning ....... 245

Smooth dull finish and receipt for seasoning; Finish for colored skins . . 246 Various ways of finishing India -tanned skins; Retanning with chrome liquor. 247 Finishing India-tanned leather into book-binding leather; Shaving and coloring the skins . 248

XIV CONTENTS.

PAGE

Coloring to obtain marble effects ......... 249

Giving grain or the morocco finish to the leather ...... 250

Uses of the splits taken from India-tanned leather; Skins for boarded gi*ains. 251 Ooze or suede leather; Properties and uses of this variety of leather; Skins suitable for the purpose; Methods used in finishing India-tanned ooze leather ............. 252

Chrome leather from India-tanned kips; Eetanning and finishing this kind of

Washing the kips ............ 254r

Coloring and finishing the leather; Patent tipping from India-tanned kips . 255

SECTION FIVE. The Manufacture of Goatskin Leather

Soaking the skins; Loosening the hair; Liming ...... 257

New process for liming goatskins; Bating; Essential qualities of goatskin leather ............. 259

Bating with bird dung; Preparation of a chicken manure bate . . . 260 Test for determining when the skins are bated ; Apparatus for bating . . 261 Manipulation of the skins after bating; Bating \\dth formic and lactic acids . 262 Bating with puerine; Pickling with acid and salt; Beamhouse process for cabretta skins. ............ 263-

Process of tanning goatskins; Tanning by the two-bath process . . . 265-

Preparation of the second bath . 266

Washing the skins 267

Method of acid tanning different from the regular two-bath process . . 268 Another patented method .......... 269

Tanning with one-bath processes ......... 270

Tanning with sulphate of alumina, sal soda and chrome liquor; Tanning with sulphate of alumina and chrome liquor . . . . . . .271

Method of keeping skins for some time after they are bated .... 272

Methods of dyeing goatskins black; Dyeing with logwood and titanium salts; Dyeing with logwood and bichromate of potash; Dyeing with logwood, acetic acid and nitrate of iron ......... 273

Dyeing with logwood, permanganate of potash, and iron liquor . . . 274 Dyeing with logwood and copperas; Processes of coloring chrome-tanned goatskins; Most common method of coloring with aniline dyes .... 275

Preparation of the skins for dyeing; Temperature of the coloring solutions . 276 Sumac mordant; Garabier mordant ........ 277

Fustic mordant; Palmetto mordant; Other mordants; Clearing the grain of grease ............. 278

Dyeing with natural dyestufis; Light tan; Dark tan ..... 279

Ox-blood shade; Chocolate brown; Dyeing with aniline dyes; Keceipts for some popular shades ........... 280

Water for dyeing; Coloring after fat-liquoring with sulphonated oil . . 281 Fat-liquors for colored and black goatskins ....... 282.

CONTENTS. XV

PAGK

Receipts for fat-liquors ........... 283

Oiling, drying and staking . " . . . . . . . . . 285

Clearing the grain of grease and receipts for this purpose; Receipts for seasonings for glazed finish ........... 287

Dull finish 289

Processes for white goat leather; Tanning with sulphate of alumina . . 290

Tanning with alum, flour and salt ........ 291

Mocha castor glove leather; Liming, drenching and tanning the skins for this

Treatment for colored skins .......... 293

SECTION SIX. Chkome-Tanned Sole Leather

Most essential points to be observed in the manufacture of this leather; Selection of hides; Soaking the hides ........ 294

Bating; Pickling 296

Processes of pickling with sulphate of alumina and salt, and with sulphuric acid and salt; Methods of tanning ........ 297

Tanning hides pickled with alumina and salt ...... 298

Tanning liquor for acid pickled stock; Fat-liquoring and water-proofing the

leather; Chrome-tanned harness leather; Precautions in handling the hides. 299 Liming; Bating; Preparation of chicken manure bate ..... 300

Bating with lactic acid; Pickling; Processes of tanning .... 301

Blacking and stuflang; Preparation of the logwood liquor and of the stuffing. 303 Finishing the leather; Chrome-tanned belt and strap leathers; Hides for this purpose; Tanning the butts ......... 304

Fat-liquoring the tanned butts, and preparations for this puipose; Eetanning the trimmings ............ 305

Strap leather; Beamhouse treatment and tanning; Fat-liquoring; Finishing, and preparation of the finish for this pui-pose ...... 306

SECTION SEVEN. The Manufacture of Genuine Kangaroo Leather

Properties of kangaroo skins, and their derivation; Softening and soaking kangaroo and wallaby skins ......... 307

Use of sulphide of sodium in the soak; Liming ...... 308

Bating and drenching; Bating with bacterial bate ..... 310

Bating with lactic acid; Bating with bi-an ....... 311

Pickling; Chrome-tanned kangaroo leather; Two-bath process . . . 312 One-bath process ............ 313

Methods of dyeing kangaroo skins; Receipts for dyeing the skins black . . 315 Fat-liquor formulas . . . . . . . . . . .317

XVI CONTENTS.

Oiling and drying the leather; Staking and tacking; Finishing; Di-essing for glazed finish ............ 319

Vegetable-tanned kangaroo skins; Quebracho-tanned kangaroo Combination-tannages ........

Finishing combination-tanned leather . . . .

Dongola tannages .........

Yellow flesh on quebracho or combination-tanned leather. Blue or black flesh on quebracho or combination-tanned leather; A patented method of finishing kangaroo leather. ....... 32o

SECTION EIGHT. Methods of Bleaching Leather

Bleaching sole leather; Wyandotte Tannei*s Alkali and Wyandotte Tanners Soda; Laws governing the results of bleaching; Consumption of bleaching material by sole leather tanners. . . . . . . . . 327

Apparatus for bleaching; Amount of alkali required for bleaching. . . 328 Invariable action of an alkali; Calculation of the amount of alkali to keep the bleach strength at its full efficiency ........ 329

On what the amount of alkali required depends; Bleaching bag, strap and collar leather; Single-bleach formula. . . . . . ... 330

Double bleach; Kinse liquor . . . . . . . . . .331

Production of a still lighter color; Bleaching with sumac, boi^ax and sulphuric acid . . . . . . . . . . . . 332

Bleaching with sugar of lead and sulphuric acid ...... 333

Bleaching with gold dust washing powder and acid ..... 334

Bleaching with hydrosulphites; Pi'eparation of hydrosulphites . . . 335 Bleaching with bisulphite of soda, with sodium peroxide, and with pemianganate of potash ............ 336

Bleaching, stufling and finishing russet skirting leather. .... 337

Bleaching with borax and lactic acid ........ 338

Clearing leather with alum and salt . . . . . . . . 339

Bleaching with oxalic acid . . . . . . . . . . 340

Bleaching chrome leather; Bleaching with tanning material, alkali and acid. 341 Amount of alkali to be added to the solution of tanning material; Constitution of the acid bath ........... 342

Procedure in bleaching hemlock-tanned sole leather ..... 343

Maintaining the acidity of the acid bath; Advantages of this mode of ti"eatment ............. 344

Method of bleaching sole leather by hand; Bleaching and finishing russet

Colorless dressing for russet leather ........ 34(i

Bleaching mill-stuffed harness leather ........ 347

CONTENTS. XV 11

PA(iK

SECTION NINE. The Tanning of Furs and Hair Skins

Dry tanning; Preparation of the tanning paste 349

Good formula for the tanning paste; Tanning with bran, alum and salt . 350

Tanning with gambler, alum and salt; Washing greasy skins . . . 351

Chrome-tanned furs and hair skins; A good tanning process for this purpose. 352 Another process; Pickling the skins; Preparation of the tanning bath . . 353 Another good tanning process ......... 354

Oiling alum-tanned skins; Tanning dogskins . . . . . . 355

Keceipt for deodorizing furs and skins; How to clean furs; Cleaning dark

Tanning of hides for robes, coats, etc.; Soaking the hides; Use of borax and

of salt solution for softening 357

Ti-eatment of hides in a partially tanned condition; Alum and salt process . 358 Dressing or cutting down to a light substance; Eetanning .... 359 Combination-tannage; Softening and cleaning the hides .... 360

Tanning of calfskins and other hair skins . . . . . . • 361

SECTION TEN. MlSCEIiLANEOITS PROCESSES OP TaNNING, CoEOEING AND FINISHING LEATHER

How to make and use acid fat-liquor; Acid fat-liquor of castor oil . . 362

Acid fat-liquor of neatsfoot and cod oils 363

How to use the acid-treated oils; How to color chrome-tanned skins with

sumac and aniline dyes; Method of mordanting ..... 365

Another method of preparing the skins for aniline coloring; Process of dyeing. 366 Eetanning with gambler and sumac; Good retanning liquor for harness and

other leathei-s • • 367

Retanning of bark and extract-tanned leather; Retanning with sumac; Tanning with gambler, sumac and oak extract ...... 368

Process of coloring chrome leather after fat-liquoring, described by Mr.

Charles Lamb 369

Degreasing skins and leather; Removal of the natural grease in sheepskins . 371 Removal of the natural grease from pickled sheepskins; Treatment with naphtha . . .... ....... 372

Purification of skins from gummy matters due to the use of an unsuitable oil, 373 Method of degreasing leather and degreasing plant; Degreasing of sheepskins; W. Eitnei''s vicAvs on this subject . . . . . . . . 374

Mode of degreasing sheepskins in Argentina ....... 375

Constitution of sheepskin fat; Retanning degreased sheepskins . . . 376 Pigskin leather; Washing and degreasing pigskins ..... 377

Unhairing, liming and bating pigskins ........ 378

Tanning pigskins; Quebracho tannage ........ 379

Tanning with siimac, oak bark and alum 380

XVlll CONTENTS,

pagf:.

Treatment with sumac after tanning; White pigskins ..... 381

Mode of tanning white pigskin leather ........ 382

Treatment of dry hides and skins; Loss by prolonged soaking; Means for hastening the process of soaking ........ 383

Advantages of sulphide of sodium as a softener; Prevention of decay . . 384 Office of any material that is used to remove the hair; Process of using sulphide of sodium upon dry hides 385

Treatment of skins for some kind of leather 386

Preparation of goatskins for tanning; Manipulation of hides for sole leather . 387 Plumping dry hides that are to be split after unhairing; Titanium mordants on chrome and vegetable-tanned leather; Compounds of antimony as mordants ............. 388

Distribution of titanium in nature; Characteristics of titanium . . . .389

Advantages of titanium mordants. ........ 390

Examples for one hundred pounds diy vegetable-tanned, and for one hundred pounds of wet chrome-tanned goat, sheep, calf skins, etc.; Titanium for black leathers with logwood ......... 391

Examples for one hundred pounds of dry vegetable-tanned skins, and for one

hundred pounds of wet chrome-tanned leather 392

Blacks with aniline colors; Example for two hundred and fifty pounds of dry vegetaWe-tanned skins lightly retanned ; Remarkable properties of titanium potassium oxalate ........... 393

Notes on the manufacture and application of fat-liquors; Importance of the discovery and application of the fat-liquors to the success of the chrome leather industry; Pui-pose of the fat-liquor; Use of oil in the old days of

bark-tanned leather 394

Robert Foederer probably the inventor of the emulsified fat-liquor; Definition

of an emulsion; Emulsifying agents; Use of soap as an emulsifying agent . 395 Sulphonated oils; Turkey oil and the use of castor oil in its preparation; vSul-

phonating fatty acids 396

Sulphonating linseed oil and oleic acid; Casein and its use as an emulsifying

agent; Egg yolk as a constituent of fat-liqiaoi-s 397

Potash soaps as a soap constituent of fat-liquor; Objections to soda soaps; Test

for distinguishing between potash and soda soaps 398

Fig soap; Objections to rosin oil; Alkalinity or acidity of fat-liquoi-s . . 399 Removing spots and stains from leather, and various methods for this purpose. 400 How to retan chrome leather ......... 402

How to test neatsfoot oil; Cold test; Maumene test 404