Transcriber Note
Emphasized text is displayed as _Italic_.
Except in tables where the characters ¼ and ½ were used,
whole and fractional numbers are shown like: 36-1/8.
THE
SILVERSMITH'S HANDBOOK
BY THE SAME AUTHOR, UNIFORM WITH THE PRESENT VOLUME.
_Ninth Impression, price 5s. net, cloth._
THE GOLDSMITH'S HANDBOOK,
CONTAINING
FULL INSTRUCTIONS FOR THE ALLOYING AND WORKING OF GOLD.
Including the Art of Alloying, Melting, Reducing, Colouring,
Collecting, and Refining; The Processes of Manipulation, Recovery of
Waste; Chemical and Physical Properties of Gold; with a New System
of Mixing its Alloys, Solders, Enamels, and other Useful Rules and
Recipes.
_Crown 8vo, price 3s. 6d. net, cloth._
THE
HALL-MARKING OF JEWELLERY,
PRACTICALLY CONSIDERED.
Comprising an account of all the different Assay Towns of the United
Kingdom, with the Stamps at present employed; also the Laws relating
to the Standards and Hall Marks at the various Assay Offices; and a
variety of Practical Suggestions concerning the Mixing of Standard
Alloys, and other Useful Information.
CROSBY LOCKWOOD & SON,
7, Stationers' Hall Court, Ludgate Hill, E.C.
THE
SILVERSMITH'S HANDBOOK
CONTAINING
FULL INSTRUCTIONS
FOR THE
_ALLOYING AND WORKING OF SILVER_
INCLUDING THE DIFFERENT MODES OF REFINING AND MELTING
THE METAL; ITS SOLDERS; THE PREPARATION OF IMITATION
ALLOYS; METHODS OF MANIPULATION; PREVENTION OF
WASTE; INSTRUCTIONS FOR IMPROVING AND
FINISHING THE SURFACE OF THE WORK
TOGETHER WITH OTHER USEFUL
INFORMATION AND MEMORANDA
By GEORGE E. GEE
GOLDSMITH AND SILVERSMITH
AUTHOR OF "THE GOLDSMITH'S HANDBOOK," "THE HALL-MARKING OF JEWELLERY,"
ETC. ETC.
Fifth Edition
[Illustration]
LONDON
CROSBY LOCKWOOD AND SON
7, STATIONERS' HALL COURT, LUDGATE HILL
1921
PRINTED BY
WILLIAM CLOWES AND SONS, LIMITED,
LONDON AND BECCLES.
PREFACE.
The object of this Treatise is to supply a want long felt in the Silver
Trade, namely, a work of reference from which workmen, apprentices,
and manufacturers, employing the material upon which it treats, may
find information which will be of assistance to them in the performance
of their daily duties, and by which their operations may be rendered
more successful. The Author was led to undertake the present work
from having had many opportunities, during his lengthened experience
in the art of silver-working, of observing the difficulties and
stumbling-blocks that are constantly to be met with in the manifold
branches of this important trade, by those _practically_ engaged in it,
and also by those persons who are desirous of acquiring a _thorough_
knowledge of the mechanical and manipulative details belonging to it.
To assist his object, numerous illustrations have been prepared for
this Treatise, with the view of rendering the various processes of the
art more readily comprehensible, and to save a lengthened or detailed
description of them.
The different modes of alloying and melting silver; its solders; the
preparation of imitation alloys; methods of working; the prevention
of waste; instructions for improving and finishing the surface of the
work, together with other useful information and memoranda--all these
have been carefully collected and placed in order in the body of the
work.
The Author has endeavoured, throughout, to present the contents (which
he has with some little difficulty and labour brought together) in
as practical and readable a form as is compatible with accuracy and
efficiency.
G. E. GEE.
PREFACE TO THE SECOND EDITION.
Since the publication of the first edition of this work important
changes have taken place in the commercial value of silver, its
present cost in the best markets being sixpence per ounce lower than
it was when this volume first appeared in 1877. This depreciation in
value has, of course, necessitated a thorough revision of the former
prices of the various alloys, solders, and other substances mentioned
throughout the work; and this has been done in order to render it the
more complete as a work of general reference, conveying correct and
useful information to the reader. The Author trusts that his endeavours
in this direction will be appreciated.
58, Tenby St. North, Birmingham.
_February, 1885_.
PREFACE TO THE FOURTH EDITION.
In issuing the present edition, a few introductory remarks are
necessary to explain that numerous revisions have been made in Chapters
VI. and VII. (by means of the Tables referred to below) regarding the
cost prices of the different alloys, solders, etc., which I trust will
increase the value of the book.
Through the repeal of the silver duty in the year 1890, a great
impetus has been given to the Silver industry of this country, and
notwithstanding the length of time that has elapsed since this book was
first published, a steady demand has continued for its possession by
workers in the precious metal trades--a fact which is gratifying to the
Author, not only because a reprint is again called for, but as showing
that the work has held its position, and may now justly claim to be a
standard authority on the subject of which it treats.
It has not been found necessary to interfere with the general
processes embodied in the book, as they are practically the same as
formerly; but as regards the commercial value of silver, there is
again a considerable depreciation[A] to record on the prices prepared
for the second edition in 1885, and it becomes imperative that this
depreciation should be dealt with in this new edition, in order to
bring the work up to date.
[A]
_s._ _d._
In 1877 fine silver cost 5 2 per ounce.
" 1885 " " 4 8 "
" 1906 " " 3 0 "
The market price of silver has for many years been of a very variable
nature, almost each day's prices showing a difference, so that it would
be impossible to provide the reader with an unvarying fixed price per
ounce. The best and most practical thing to do under the circumstances,
it seemed, was to carefully revise the different cost prices of the
alloys and solders specified in Chapters VI. and VII. and give them by
way of approximate Tables, compiled for each chapter separately. These
two Tables follow this Preface (making pp. ix. and x.) and will serve
as a ready reference for present workers in the silver trades. Thus,
by bringing the figures down to date, the work may still retain its
reliable character as a practical guide to the silversmith's workshop.
G. E. GEE.
58, Tenby St. North, Birmingham.
_January, 1907._
PUBLISHERS' NOTE TO FIFTH EDITION.
In February 1921 silver was quoted at 34-1/2_d._ to 36-1/8_d._, and it
is therefore sufficient to note that the prices at that date correspond
approximately to those current in 1907. It should be noted that the
melting of British gold and silver is prohibited, as well as their
export.
Table of Revised and Up-to-date Cost Prices of the Different Alloys in
Chapter VI.
+-----+----------------------+-------------------+---------------------+
|Page.| No. and quality of | Cost price 1885. | Cost price 1907 |
| | alloy. | | and 1921. |
+-----+----------------------+-------------------+---------------------+
| 61 | Old standard alloy | _For_ 4/4 per oz. | _read_ 2/9½ per oz.|
| 62 | New standard alloy | " 4/6 " | " 2/10½ " |
| 64 | No. 1, silver alloy | " 4/2 " | " 2/9 " |
| 64 | No. 2, silver alloy | " 3/9 " | " 2/5½ " |
| 65 | No. 3, silver alloy | " 3/6 " | " 2/3½ " |
| 65 | No. 4, silver alloy | " 3/3 " | " 2/1½ " |
| 66 | No. 5, silver alloy | " 3/2 " | " 2/0½ " |
| 66 | No. 6, silver alloy | " 3/1 " | " 2/- " |
| 67 | No. 7, silver alloy | " 3/- " | " 1/11 " |
| 67 | No. 8, silver alloy | " 2/10 " | " 1/10 " |
| 70 | French coinage alloy | " 4/2 " | " 2/9 " |
| 70 | French plate alloy | " 4/5 " | " 2/10 " |
| 70 | French 0·800 alloy | " 3/9 " | " 2/5½ " |
| 72 | German coinage alloy | 0·900 standard | " 2/9 " |
| 72 | German silver wares | | |
| | alloy | 0·950 1st standard| " 2/10¼ " |
| 73 | Ditto | 0·800 2nd " | " 2/5½ " |
| 73 | Ditto | 0·750 3rd " | " 2/3½ " |
+-----+----------------------+-------------------+---------------------+
This Table is based on the market price of fine silver being 3/- per
ounce.
Table of Revised and Up-to-date Cost Prices of the Different Solders in
Chapter VII.
+-----+---------------------------+-----------------+-------------------+
|Page.| Quality of solder. |Cost price 1885. | Cost price 1907 |
| | | | and 1921. |
+-----+---------------------------+-----------------+-------------------+
| 78 |Hardest silver solder |_For_ 3/9 per oz.|_read_ 2/5½ per oz.|
| 79 |Hard silver solder | " 3/6 " | " 2/3½ " |
| 79 |Easy silver solder | " 3/2 " | " 2/0½ " |
| 81 |Best silver solder | " 3/9 " | " 2/5½ " |
| 82 |Medium silver solder | " 3/6 " | " 2/3½ " |
| 82 |Easy silver solder | " 3/3 " | " 2/1½ " |
| 83 |Common silver solder | " 3/- " | " 1/11 " |
| 84 |Enamelling silver solder | " 3/9 " | " 2/5½ " |
| 84 | Ditto | " 3/2 " | " 2/0½ " |
| 84 |Filigree solder | " 3/9 " | " 2/5½ " |
| 85 |Quick-running silver solder| " 3/- " | " 1/11 " |
| 85 |Silver solder for chains | " 3/- " | " 1/11 " |
| 85 |Easy solder for chains | " 3/- " | " 1/11 " |
| 85 |Common silver solder | " 2/9 " | " 1/9 " |
| 86 |Common easy solder | " 2/9 " | " 1/9 " |
| 86 |Arsenic silver solder | " 3/9 " | " 2/5½ " |
| 86 | Ditto | " 3/6 " | " 2/3½ " |
| 86 |Easy silver solder | " 3/2 " | " 2/0½ " |
| 87 |Common easy silver solder | " 2/9 " | " 1/9 " |
+-----+---------------------------+-----------------+-------------------+
This Table is based on the market price of fine silver being 3/- per
ounce.
CONTENTS.
INTRODUCTORY CHAPTER.
Page
Silver a Precious Metal 1
Economy of Treatment 1
Working Silversmiths 2
English and Foreign Workmen 2
Technical Education 2
Pure Silver 3
Plate and Ornamental Wares 4
CHAPTER I.
_Silver._
Silver, Characteristics of 5
Silver for Filigree Work 5
Indian Filigree Workers 5
Malleability of Silver 6
Ductility of Silver 6
Test for Pure Silver 6
Silver known to the Ancients 6
Silver Currency 6
Polished Silver 7
Tarnishing of Silver 7
Density of Silver 7
Fusibility of Silver 7
Heating Power of Silver 7
Action of Silver under Great Heat 8
Hardness of Silver 8
Nitrate of Silver 8
Silver resists Aqua-regia 8
Chief Places of Filigree Manufacture 8
Chief Uses of Silver 9
Price of Silver, Commercial 9
Ores of Silver 9
Dissolution of Silver 9
Caustic Alkalies 10
Nitre 10
Vegetable Acids 10
CHAPTER II.
_Sources of Silver._
Silver-mining 11
Great Britain 11
British Isles' Yield of Silver 11
Spain 11
America 11
Native Silver 11
European Supplies of Silver 12
American Supply of Silver 12
The Richest Mine 12
State of the Jewellery Trade 12
Yield of Silver 13
Foreign Silver Currency 13
Chief Sources of British Silver 13
State in which it is found 14
CHAPTER III.
_The Assay of Silver Ores._
Silver and Mercury 15
Assaying of Silver Ores 16
Crucible Assay 16
Fluxes for Crucible Assay 16
Assay of Genuine Silver Ores 16
Carbonate of Soda 16
Dimensions of Crucible 16
Litharge 17
Preparation and Charge for Assay 17
Treatment in the Furnace 18
Casting-mould 18
Scorification Process 18
Fusing Cup or Scorifier 19
Special Form of Scorifier 19
Scorification Assay the Reverse of Crucible Assay 19
Charge for Scorification Assay 20
Advantages of the Process 20
Anthracite and its Object 21
Separation of the Silver from the Slag 21
Borax, use of, in Assaying 22
Continental Method of Assaying 22
Flux and Charge for Crucible 23
Details of the Process 23, 24
Skittle-pot 25
Cupellation 26
Cupel, its Mode of Manufacture 26
Cupel-mould 27
Assayer's Muffle 28
Cupel-tongs 28
Brightening 29
Sprouting 29
Weighing of Silver Assay 30
Chief Alloy of Silver 30
CHAPTER IV.
_The Cupellation of Silver Ores._
Test-ring 31
Preparation of Bone-ash 32
Defects in Bone-ash Cupel 33
Currents of Air to the Furnace 33
Withdrawal of the Silver from the Cupel 34
Removal of the Litharge, Manner of 35
Quantity of Alloy per Cupel 35
Purity of Silver after Cupellation 37
Ancient Method of Assaying 37
Dr. Lamborn on Assaying 38
Scriptural Testimony 37, 38
English System of Assay 39
CHAPTER V.
_The Alloys of Silver._
Silversmith's Alloys 40
Filigree Work 40
Alloy 41
Amalgam 41
Metals employed in the Industrial Arts 41
Metals, their various Characteristics 41
Principal Alloys of Silver 42
Copper 42
Characteristics of Copper 43
Protoxide of Copper 44
Action of Acids on Copper 44
Bean-shot Copper for Alloying 44
Chemical name for Copper 44
Nickel 45
Cronstedt 45
Density of Nickel 45
Ductility of Nickel 45
Malleability of Nickel 45
Fusibility of Nickel 45
Nickel Coinage 45
Nickel Alloys 46
Electro-plate 46
Zinc 46
Spelter 46
Zinc in Silver Solder 46
Annealing of Zinc 47
Specific Gravity of Zinc 47
Spelter used by Jewellers 47
Tarnishing of Zinc 47
Malleability of Zinc 48
Ductility of Zinc 48
Tenacity of Zinc 48
Tin 48
Ancient Workers in Tin 48
Density of Tin 48
Christianity and Tin 48
Fusibility of Tin 48
Dissolving of Tin 48
Tin alloyed with Gold 49
Tin alloyed with Silver 49
Tin in Silversmith's Solders 49
Vapours of Tin injurious to Gold 49
Malleability of Tin 49
Ductility of Tin 49
Tenacity of Tin 49
Scientific Name for Tin 50
Table of Metallic Elements 50
Melting-points of the Principal Metals 51
Physical Properties of the Principal Metals 51
CHAPTER VI.
_Various Qualities of Silver._
Mechanical Uses of Silver 52
Filigree Work 52
Birmingham 52
London 52
Indian 53
Chief Places of Filigree Manufacture 53
Continental Cheap Labour 54
Hand-made Articles 54
Process of Workmanship 55
Maltese Filigree 55
Chinese and Japanese Filigree 56
Filigree of Norway and Sweden 56
Filigree working, Necessity for Pure Metal 56
Old Method of making Filigree 57
Twisting of the Wire 58
Lathe, Use of 58
Flattening of Twisted Wire for Filigree 59
New Method of preparing Filigree Wire 59
English Standards for Silver 60
English Coinage 61
Standard Silver Alloy 61
Alloy for Hall-marking 62
Standard Alloy of the Highest Quality 62
Standard Alloy for Hall-marking 62
Alloy commonly used in England 63
Qualities used by English Silversmiths 63
Drawbacks to Hall-marking 63
Method of calculating the Qualities of Silver 63
Silver Alloy No. 1, cost 4_s._ 7_d._ per oz. 64
" No. 1, differently calculated 64
" No. 2, cost 4_s._ 1_d._ per oz. 64
" No. 2, differently calculated 64
" No. 3, cost 3_s._ 10_d._ per oz. 65
" No. 3, differently calculated 65
Silver Alloy No. 4, cost 3_s._ 7_d._ per oz. 65
" No. 4, differently calculated 65
" No. 5, cost 3_s._ 6_d._ per oz. 66
" No. 5, differently calculated 66
" No. 6, cost 3_s._ 3_d._ per oz. 66
" No. 6, differently calculated 66
" No. 7, cost 3_s._ 2_d._ per oz. 67
" No. 7, differently calculated 67
" No. 8, cost 3_s._ per oz. 67
" No. 8, differently calculated 67
Instructions in the Preparation of Alloys 68
Copper for Alloying 68
French Standards 69
Silver Ware 69
Coinage 69
French Alloy for Coinage 70
French Alloy for Plate 70
French Alloy for Silver Ware 70
Instructions in the Preparation of these Alloys 70
German Standards 71
Silver Ware 71
Coinage 71
Silver Alloy for the German Coinage 72
Alloy for Plate 72
Alloys for Silver Wares 72, 73
Law on the Manufacture of Silver Wares 73
Remedy allowed in Fineness 73
Government Exports 73
Guarantee Marks 73
CHAPTER VII.
_Silver Solders: their Uses and Applications._
The Act of Soldering 74
Cause of Inferior Manufactures 74
Tin in Solders 75
Filed Solders 76
Zinc in Silver Solder 76
Solders made with Copper and Silver 76
Hard Silver Solders 77
Medium Solders 77
Easy Solders 77
Connections for Soldering 77
Flux for Soldering 77
Fusibility of Silver Solders 78
Hardest Silver Solder, cost 4_s._ 1_d._ per oz. 78
Ditto, differently calculated 79
Medium Silver Solder, cost 3_s._ 10_d._ per oz. 79
Ditto, differently calculated 79
Easy Silver Solder, cost 3_s._ 5_d._ per oz. 79
Ditto, differently calculated 80
Remarks on Silver Solders 80
Composition for Solder 81
Best Hard Solder, cost 4_s._ 1_d._ per oz. 81
Ditto, differently calculated 81
Medium Solder, cost 3_s._ 10_d._ per oz. 82
Ditto, differently calculated 82
Easy Solder, cost 3_s._ 7_d._ per oz. 82
Ditto, differently calculated 82
Common Solder, cost 3_s._ 3_d._ per oz. 83
Ditto, differently calculated 83
Directions on the Melting of Solders 83
Solder for Enamelling, cost 4_s._ 1_d._ per oz. 84
" " cost 3_s._ 6_d._ per oz. 84
Easy Solder for Filigree Work 84
Quick Running Solder, cost 3_s._ 3_d._ per oz. 85
Silver Solder for Chains, cost 3_s._ 3_d._ per oz. 85
Easy Solder for Chains, cost 3_s._ 3_d._ per oz. 85
Common Silver Solder, cost 3_s._ per oz. 85
Common Easy Solder, cost 3_s._ per oz. 86
Arsenic Solder, cost 4_s._ 1_d._ per oz. 86
Silver Solder with Arsenic, 3_s._ 10_d._ per oz. 86
Easy Silver Solder, cost 3_s._ 6_d._ per oz. 86
Common Easy Solder, cost 3_s._ per oz. 87
Another Common Solder 87
Very Common Solder 87
Directions in the Preparation of Solders 87
Drossy Solders 88
Mode of Soldering Gold and Silver 88
Pallion Solder 88
Blowpipes 89
Solder-dish and Charger 89
Soft Solder 90
Art in Soldering 90
Solder for Filigree 91
Lemaille Solder 91
English Filigree Workers 91
Sprinkle Borax 92
Special Soldering Flux 92
Boiling-out Pickle 93
CHAPTER VIII.
_On the Melting of Silver._
Directions on Melting 94
Weighing Metal for the Crucible 94
Crucibles 95
Best Crucibles to employ 95
Fluxes: their Action on Crucibles 96
Fluxes employed in Melting 96
Testing the Soundness of a Crucible 97
Mixing various Metals for melting 97
Zinc a fusible Metal 98
Charcoal 99
Bad working Material 99
Plumbago Crucible for Melting 99
Tongs for Melting 100
Ingot-mould 100
Flux and the Pouring of Molten Metal 101
Protoxide of Zinc 102
Scrap Silver 102
Carbonate of Soda 102
Dissolving Impurities 103
Lead and Tin in Silver 103
Sal-ammoniac 103
Lemel 103
Mixture prepared for Crucible 104
Burning of Lemel 104
Skittle-pot for Lemel 104
Melting of Lemel 105
Another Mode of melting Lemel 106
Crucible for Lemel 106
Pouring of Lemel from Crucible 107
CHAPTER IX.
_On the Working of Silver._
Rolling Silver 108
Annealing Silver 109
Irregularities in Rolling-mills 110
Messrs Kemp's Mill 110, 111
Table of the Cost of Silver-rolling 112
Slitting Rollers 112
Breaking-down Rollers 112
Wire-rolling 113
Wire-drawing 113
Draw-plate 114
Draw-bench 110, 115
Draw-tongs 115
Drum used by Wire-drawers 115
Fine Wire-drawing 115, 116
Wire-drawer's Punch and Hammer 117
Wrought Work 118
Sparrow-hawk 119
Raised Work 120
Cement for Chasers 121
Snarling-tools for Raising 122
Art in the Silver Trade 123
Burnished Silver Work 124
Silver Filigree Work 125
Stamped or Struck-up Work 126
Press 127
Plain Solid Work 127
Chain Bracelets 128
Present State of Silver Trade 128
Silver, Liability to become tarnished 129
Enamelling 129
Galvanic Ring 129
Mode of preparing Ring 129, 130
Hollow Silver Work 131
Stamping-press 132
Spinning 134, 135
Polishing 135
Water-of-Ayr Stone 136
Polishing-lathe 137
Washing-out Mixture 138
CHAPTER X.
_Enriching the Surfaces of Silver._
Production of the best and richest Surface 139
Oldest Method for Whitening 140
East Indian Silversmiths 141
Indian Mode of Whitening Silver 142
Another Mode of Whitening 142
Boiling-out Pan 143
Boiling-out Mixture 143, 144
Our Mode of Whitening 145
Surface Refining of Silver 146
Brown Colour on Silver Goods 146
Common Articles of Silver 147
Whitening Powder or Mixtures 147
Nitrate of Silver Mixture 148
Improving the Colour of Electro-plate 149
Electro-plating 149
Discoverer of Electro-plating 149, 150
Constant Battery 150
Best Battery for Plating 151
Strength of Battery Solution 151
Bunsen's Battery 152
Exciting Mixture for Battery 152
Zinc Amalgamation 153
Conducting Wires 154
Preparation of Plating Solution 155
Cyanide Solution 156
Black Cyanide 157
Strength of Plating Solution 157, 158
Inferior Plating Solution 159
Recovery of Silver from Plating Solutions 160
Scratch-brushing 161
Scratch-brush Lathe 161
Burnishing Silver Work 161, 162
Oxidizing Silver Work 163
Solution No 1. 163
Solution No 2. 164
Solution No 3. 164
Producing various Shades 165
CHAPTER XI.
_Imitation Silver Alloys._
Melting Imitation Alloys 166
Common Silver Alloy 167
Another 167
Another 168
Another 168
Another 168
Another 168
Another 169
Another 169
Another 169
Another 169
Another 170
Another 170
Chinese Silver 170
Imitation Silver 170
Another 171
Another 171
Another 171
Another 171
White Alloy 172
Clark's Patent Alloy 172
White Alloy 172
Alloy with Platinum 172
Alloy with Palladium 173
Uses for Imitation Alloys 173
Characteristics of Imitation Alloys 174
CHAPTER XII.
_Economical Process._
Working Loss 175
Lowest Estimate Real Loss 175
Total Working Loss 176
Shop Floors 177
Waste-saving Precautions 177, 178
Treatment of Waste 178
Burning of Polishings 179
Treatment of Waste Liquids 180
Processes for the Recovery of Silver from Waste Waters 180, 182
Chloride of Silver 183
Aqua-regia 183
Precipitating Silver in Waste Waters 183
Solution for Precipitation 184
Sediment in Collecting-vessels 185
CHAPTER XIII.
_Licences and Duties._
Acts of the Legislature 186
43 George III., c. 69 186
6 George I., c. 11 187
31 George II., c. 32 188
32 George II., c. 14 188
24 George III., c. 53 188
37 George III., c. 90 188
44 George III., c. 98 189
55 George III., c. 185 189
Table of Various Duties 189
Manufactured Plate 190
Remarks on the Licence Question 191, 196
Act of Parliament in Licences 193
Clause of Act 193, 194
Tax or Licence unjustly Assessed 195, 196
CHAPTER XIV.
_Useful Information for the Trade._
Silversmith's Alloys 197
Silver Wares 197
Cleaning Plate 198
Imitation Silver 198
Another 198
Removing Gold from Silver Articles 198
Oxidizing Silver 198
Dipping Mixture 199
Silver Powder for Copper 199
Powder for Silver 200
To protect the Polish of Metals 200
Silver-stripping Mixture 200
Stripping Silver 201
Soft Solder 201
Soldering Fluid 201
Dissolving Silver 202
Dissolving Silver Alloy 202
Dissolving Copper 202
Dissolving Soft Solder 202
Dissolving Silver Solder 202
Dissolving Sealing-wax 202
Resist Varnish 202
Plate Powder 202
Electro-plating Soft Solder 202
Another Recipe 203
Testing Silver Wares 203
Another Test 204
Perchloride of Iron 205
Aluminium Alloy 205
New Alloy 205
Removing Gold from Silver Wares 205
Silver Plating Fluid 206
Plate-cleaning Powder 206
Solder for Aluminium 206
CHAPTER XV.
Foreign Silver Standards 207
French Work, Duty on 208
Continental Silversmiths 209
French Style of Work 209
German Style of Work 210
Indian Style of Work 210
Austrian Style of Work 211
English Style of Work 211
Index 212
THE
SILVERSMITH'S HANDBOOK.
INTRODUCTORY CHAPTER.
In reviewing the rise and progress of the silversmith's beautiful and
interesting art, in its relation to the manufacture of articles of
personal ornament and luxury at home and abroad, we may observe at the
outset, that the material of which they are composed differs widely
in character from that employed by the ordinary "metalsmiths" and the
manufacturer of "electro-plated wares." Silver, the material of which
we are now treating, being a precious metal and of considerable value,
it is essentially necessary that the most careful means be exercised in
dealing with it from the commencement--that is, from the pure or fine
state--and also that the utmost economy be observed in reference to the
kind of mechanical treatment to which it is subjected in the production
of the silversmith's work, in order to prevent too great a quantity of
waste or loss of material. For it should be borne in mind that silver,
like gold, begins to lose, in one way or another, every time it is
touched; therefore, carefulness and economy will be the characteristics
of our teaching, so far as regards the present subject.
The vast majority of working silversmiths know very little of the
physical and chemical properties of the metal they employ, and still
less of the comparison it bears with other metals in the field of
science; and this want of scientific knowledge is nowhere more apparent
than in our own country, where the English workman, in art education,
is much behind the foreigner; and yet we have some of the finest and
best workmen, in their _special_ branches, in the whole world. The
English workman believes that if the work is worth doing at all, it
is worth doing well; and we have no hesitation in saying, that, if a
good technical education were afforded, concerning the precious metal
trades, he would scarcely have an equal, and certainly no superior,
abroad, in art workmanship, both in respect to the display of good
taste and judgment, combined with a knowledge of design, so far as
the exercise of these qualities is compatible with the manufacture of
articles specially designed for use and ornament.
The object of the information we are about to supply is to enable
the practical silversmith to become a perfect master of his art or
profession; and such a condition, when once achieved, will be found
of considerable assistance to him in the various kinds of manufacture
that present themselves; so that he will know how to begin a piece of
work and when to leave it off; be able to remedy a defect in the metal
when required, as well as be in a position to form an opinion as to the
relative treatment of its different alloys; all of which invariably
require different treatment.
We shall commence by describing the characteristics of _fine silver_,
carefully narrating the distinctive features of its alloys; then
give an account of the processes employed, mechanical and chemical,
in the silversmith's workshop; and conclude by pointing out the
difference between English and foreign work in regard both to style and
workmanship.
It may be thought by the reader, if uninitiated in the art, that
the costly plate and other articles made from the precious metal
are manufactured from entirely _pure_ silver, and therefore that
they possess absolute freedom from alloy; but this is not the case.
Pure silver being far too soft to stand the necessary wear and tear
of (metallic) life, it is mixed with some other metal, to give it
increased hardness. In the manufacture of plate and ornamental wares
the metal employed is always copper, in various proportions, thus
forming different commercial qualities; and of these we shall speak
hereafter. Our first object is to treat of the chemical and physical
properties of the pure metal.
CHAPTER I.
Silver.
Pure silver is, next to gold, the finest metal, but of a smoother and
more polished nature. It may be said to be almost infinitely malleable,
but it will not so easily yield or extend under the hammer as fine
gold. As a malleable metal, however, it stands next to it in this
respect. It is characterized by its perfectly white colour, being the
whitest of all the metals. It is harder than gold, yet in a pure state
it is so soft that it can easily be cut with a knife. On account of its
extreme softness, when in a pure state, it is employed for filigree
work, being utterly devoid of that elastic power which is found in the
metal when alloyed. It is for this reason that the Indian filigree
workers, who are the finest in the world, are so very particular about
the absolute purity of the metal before commencing the manufacture of
their artistic work; all of which is exceedingly beautiful.
It is reported that fine silver is capable of being beaten into leaves
of less than one-hundred-thousandth part of an inch in thickness.
For the accuracy of this statement we cannot vouch, never having had
occasion to try the experiment; its employment in that form being
unknown in the ordinary industrial pursuits. Fine silver is extremely
ductile, and may be drawn into the very finest wire without breaking,
and almost without annealing. Its purity can be partly ascertained by
the latter process; for perfectly fine silver never changes colour by
heat, whereas when it contains alloy it blackens if heated in contact
with a current of air, and soon hardens in wire-drawing.
Silver was a metallic element known to the ancients, and it is
repeatedly mentioned in the Holy Scriptures. In the time of the
patriarchs we read of it as having been constantly employed in the
transactions of nations, and that it was in use as a standard of value;
thus forming a circulating medium for the purpose of exchange. This
function it has always continued to fulfil down to the present day,
except that since the year 1816 it has not been so employed in the
English currency. However, as token money, it is everywhere recognised
as a circulating medium of trade. The Egyptian symbol for silver was
represented by Fig. 1, relating to the moon; in modern chemistry it is
understood by _ag._ from the Latin name _argentum_, denoting silver.
[Illustration: _Luna._ Fig. 1.
Egyptian mark for Silver.]
Fine silver is capable of receiving a polish scarcely inferior in
lustre to that of highly polished steel, and in this state it reflects
more light and heat than any other metal, without any perceptible
change of colour for some considerable time. It is chiefly on this
account, as well as its resistance to oxidation in air and water, that
it is used for such a variety of purposes, not only of ornament and
luxury, but also in a domestic way. Silver, unlike gold, cannot resist
the influence of sulphuretted hydrogen, from the action of which it
very soon becomes much tarnished if left exposed in damp rooms, &c.
Silver ranks next to gold in point of ductility and malleability.
When pure, its density, or specific gravity, lies between 10.47 and
10.50, taking water as 1, according to the degree of compression it
has received by rolling and hammering. It is fusible at a full red
heat, or about 1873° Fahr. It is a metal having a very low radiating
power for heat; hence silver wire of given dimensions retains and
conducts heat better than a similar piece of another metal; for the
same reason, a liquid contained in a silver vessel retains its heat
much longer than if placed in one made of some other substance. Silver
volatilises when subjected to a very great temperature in the fire,
emitting rather greenish fumes. It loses between 2/21sts and 3/25ths,
in proportion to its impurity, of its absolute weight in air when
weighed in water. In point of tenacity it occupies the fifth position
among the useful metals. In hardness it lies between copper and gold;
and a small addition of the former substance considerably increases
this quality, in which state it is largely employed in the arts. Nitric
acid is the proper solvent for silver, as it dissolves it with the
greatest ease and rapidity, forming _nitrate_ of silver, which is much
used for medical purposes, and in art. Sulphuric and hydrochloric acids
act upon it but slowly in the cold. Silver resists partially the best
aqua-regia, probably on account of the dense chloride which forms on
the surface of the metal, from the action of the hydrochloric acid in
the mixture of aqua-regia.
Fine silver is largely used in the industrial and commercial arts,
in the manufacture of silver lace and fine filigree work; the latter
branch being more commonly practised in India, Sweden, Norway, and
some parts of Germany, where labour is cheap, than in England. This
class of silversmith's work takes a long time to produce, and as
labour forms the chief item of its cost, this, not unnaturally, acts
as a great drawback in the extension of the art of very fine filigree
working, in all its intricate variety, in countries where labour is
dear. To this subject we shall subsequently refer again in detail.
Fine silver, with a small proportion of alloy, is largely used by all
nations for purposes of coinage. It amalgamates with nearly all the
metals, but is principally used in alloys suitable to the watchmaker's
and silversmith's art. The purchasable price of fine silver for
manufacturing purposes, which in 1884 was 4_s._ 8_d._ is now, 1921,
3_s._ per ounce, troy weight, varying however in value according to the
total amounts purchased; for which see refiners' and assayers' charge
lists, to be procured at the offices of any bullion dealer. The silver
ores of commerce have generally an intermixture of a small quantity
of gold, and sometimes instances have occurred in which it has been
employed in manufactures without a proper chemical investigation; and
in such cases the loss resulting from the omission would have amply
paid the expenses of the process.
Exposed to the action of hot and concentrated sulphuric acid, silver
dissolves, setting free sulphurous acid. By the application of this
process--which is one of the most advantageous methods--silver may
readily be separated from gold, sulphuric acid having no action upon
the latter metal. With the exception of gold, silver perhaps more
perfectly resists the action of the _caustic alkalies_ and the powerful
effects of _nitre_ (saltpetre) than any other metal, if we omit
platinum from the list of elements at present known to metallurgical
chemistry. For reasons such as these its superiority for the
manufacture of utensils for culinary and other domestic purposes is at
once apparent, and because it is a metal upon which _vegetable acids_
produce no effect.