III.—Copper, 5 parts; nickel, 4 parts; zinc, 1 1/2 parts; antimony, 1
part; lead, 1 part; iron, 1 part; tin, 1 part.
«Cooper’s Pen Metal.»—This alloy is especially well adapted to the
manufacture of pens, on account of its great hardness, elasticity, and
power of resistance to atmospheric influences, and would certainly have
superseded steel if it were possible to produce it more cheaply than
is the case. The compositions most frequently used for pen metal are
copper 1 part, platinum 4, and silver 3; or, copper 21, platinum 50,
and silver 36.
Pens have been manufactured, consisting of several sections, each of
a different alloy, suited to the special purpose of the part. Thus,
for instance, the sides of the pen are made of the elastic composition
just described; the upper part is of an alloy of silver and platinum;
and the point is made either of minute cut rubies or of an extremely
hard alloy of osmium and iridium, joined to the body of the pen by
melting in the flame of the oxyhydrogen blowpipe. The price of such
pens, made of expensive materials and at the cost of great labor, is of
course exceedingly high, but their excellent qualities repay the extra
expense. They are not in the least affected by any kind of ink, are
most durable, and can be used constantly for years without showing any
signs of wear.
The great hardness and resistance to the atmosphere of Cooper’s alloys
make them very suitable for manufacturing {75} mathematical instruments
where great precision is required. It can scarcely be calculated how
long a chronometer, for instance, whose wheels are constructed of this
alloy, will run before showing any irregularities due to wear. In the
construction of such instruments, the price of the material is not to
be taken into account, since the cost of the labor in their manufacture
so far exceeds this.
«PEWTER.»
This is an alloy of tin and lead only, or of tin with antimony and
copper. The first is properly called pewter. Three varieties are known
in trade:
I (Plate Pewter).—From tin, 79 per cent; antimony, 7 per cent; bismuth
and copper, of each 2 per cent; fused together. Used to make plates,
teapots, etc. Takes a fine polish.
II (Triple Pewter).—From tin, 79 per cent; antimony, 15 per cent; lead,
6 per cent; as the last. Used for minor articles, syringes, toys, etc.
III (Ley Pewter).—From tin, 80 per cent; lead, 20 per cent. Used for
measures, inkstands, etc.
According to the report of a French commission, pewter containing more
than 18 parts of lead to 82 parts of tin is unsafe for measures for
wine and similar liquors, and, indeed, for any other utensils exposed
to contact with food or beverages. The legal specific gravity of pewter
in France is 7.764; if it be greater, it contains an excess of lead,
and is liable to prove poisonous. The proportions of these metals may
be approximately determined from the specific gravity; but correctly
only by an assay for the purpose.
«SILVER ALLOYS:»
«Aluminum Silver.»—Aluminum and silver form beautiful white alloys
which are considerably harder than pure aluminum, and take a very high
polish. They have the advantage over copper alloys of being unchanged
by exposure to the air, and of retaining their white color.
The properties of aluminum and silver alloys vary considerably
according to the percentage of aluminum.
I.—An alloy of 100 parts of aluminum and 5 parts of silver is very
similar to pure aluminum, but is harder and takes a finer polish.
II.—One hundred and sixty-nine parts of aluminum and 5 of silver make
an elastic alloy, recommended for watch springs and dessert knives.
III.—An alloy of equal parts of silver and aluminum is as hard as
bronze.
IV.—Five parts of aluminum and 1 part of silver make an alloy that is
easily worked.
V.—Also aluminum, 3 parts, and silver, 1 part.
VI. Tiers-Argent.—This alloy is prepared chiefly in Paris, and used
for the manufacture of various utensils. As indicated by its name
(one-third silver), it consists of 33.33 parts of silver and 66.66
parts of aluminum. Its advantages over silver consist in its lower
price and greater hardness; it can also be stamped and engraved more
easily than the alloys of copper and silver.
VII.—This is a hard alloy which has been found very useful for the
operating levers of certain machines, such as the spacing lever of
a typewriter. The metal now generally used for this purpose by the
various typewriter companies is “aluminum silver,” or “silver metal.”
The proportions are given as follows:
Copper 57.00
Nickel 20.00
Zinc 20.00
Aluminum 3.00
This alloy when used on typewriting machines is nickel-plated for the
sake of the first appearance, but so far as corrosion is concerned,
nickeling is unnecessary. The alloy is stiff and strong and cannot be
bent to any extent without breaking, especially if the percentage of
aluminum is increased to 3.5 per cent; it casts free from pinholes and
blowholes; the liquid metal completely fills the mold, giving sharp,
clean castings, true to pattern; its cost is not greater than brass;
its color is silver white, and its hardness makes it susceptible to a
high polish.
«Arsenic.»—Alloys which contain small quantities of arsenic are
very ductile, have a beautiful white color, and were formerly used
in England in the manufacture of tableware. They are not, however,
suitable for this purpose, on account of the poisonous character of the
arsenic. They are composed usually of 49 parts of silver, 49 of copper,
and 2 of arsenic.
«China Silver.»—Copper, 65.24 per cent; tin, 19.52 per cent; nickel,
13.00 per cent; silver, 2.05 per cent.
«Copper-Silver.»—When silver is alloyed with copper only one proportion
is known which will give a uniform casting. The proportion is 72 per
cent silver to 28 per cent copper. With more silver than 72 per cent
the center of a cast bar will be {76} richer than the outside, which
chills first; while with a less percentage than 72 per cent the center
of the bar will be poorer and the outside richer than the average. This
characteristic of silver-copper alloys is known to metallurgists as
“segregation.”
When nickel is added to the silver and copper, several good alloys may
be formed, as the following French compositions:
I II III
Silver 33 40 20
Copper 37–42 30–40 45–55
Nickel 25–30 20–30 25–35
The whitening of alloys of silver and copper is best accomplished by
annealing the alloy until it turns black on the surface. Cool in a
mixture of 20 parts, by weight, of concentrated sulphuric acid to 1,000
parts of distilled water and leave therein for some time. In place of
the sulphuric acid, 40 parts of potassium bisulphate may be used per
1,000 parts of liquid. Repeat the process if necessary.
«Copper, Silver, and Cadmium Alloys.»—Cadmium added to silver
alloys gives great flexibility and ductility, without affecting the
white color; these properties are valuable in the manufacture of
silver-plated ware and wire. The proportions of the metals vary in
these alloys. Some of the most important varieties are given below.
Silver Copper Cadmium
I. 980 15 5
II. 950 15 35
III. 900 18 82
IV. 860 20 180
V. 666 25 309
VI. 667 50 284
VII. 500 50 450
In preparing these alloys, the great volatility of cadmium must be
taken into account. It is customary to prepare first the alloy of
silver and copper, and add the cadmium, which, as in the case of the
alloys of silver and zinc, must be wrapped in paper. After putting it
in, the mass is quickly stirred, and the alloy poured immediately into
the molds. This is the surest way to prevent the volatilization of the
cadmium.
«Silver, Copper, Nickel, and Zinc Alloys.»—These alloys, from the
metals contained in them, may be characterized as argentan or German
silver with a certain percentage of silver. They have been used for
making small coins, as in the older coins of Switzerland. Being quite
hard, they have the advantage of wearing well, but soon lose their
beautiful white color and take on a disagreeable shade of yellow, like
poor brass. The silver contained in them can be regained only by a
laborious process, which is a great drawback to their use in coinage.
The composition of the Swiss fractional coins is as follows:
20 centimes 10 centimes 5 centimes
Silver 15 10 5
Copper 50 55 60
Nickel 25 25 25
Zinc 10 10 10
«Mousset’s Alloy.»—Copper, 59.06; silver, 27.56; zinc, 9.57; nickel,
3.42. This alloy is yellowish with a reddish tinge, but white on
the fractured surface. It ranks next after Argent-Ruolz, which also
contains sometimes certain quantities of zinc, and in this case may be
classed together with the alloy just described. The following alloys
can be rolled into sheet or drawn into wire:
I II III
Silver 33.3 34 40.0
Copper 41.8 42 44.6
Nickel 8.6 8 4.6
Zinc 16.3 16 10.8
«Japanese (Gray) Silver.»—An alloy is prepared in Japan which consists
of equal parts of copper and silver, and which is given a beautiful
gray color by boiling in a solution of alum, to which copper sulphate
and verdigris are added. The so-called “mokum,” also a Japanese alloy,
is prepared by placing thin plates of gold, silver, copper, and the
alloy just described over each other and stretching them under the
hammer. The cross sections of the thin plates obtained in this way show
the colors of the different metals, which give them a peculiar striped
appearance. Mokum is principally used for decorations upon gold and
silver articles.
«Silver-Zinc.»—Silver and zinc have great affinity for each other, and
alloys of these two metals are therefore easily made. The required
quantity of zinc, wrapped in paper, is thrown into the melted and
strongly heated silver, the mass is thoroughly stirred with an iron
rod, and at once poured out into molds. Alloys of silver and zinc can
be obtained which are both ductile and flexible. An alloy consisting of
2 parts of zinc and 1 of silver closely resembles silver in color, and
is quite ductile. With a larger proportion of zinc the alloy becomes
brittle. In preparing the alloy, a somewhat larger quantity of zinc
must be taken than the {77} finished alloy is intended to contain, as a
small amount always volatilizes.
«Imitation Silver Alloys.»—There are a number of alloys, composed of
different metals, which resemble silver, and may be briefly mentioned
here.
I.—Warne’s metal is composed of tin 10 parts, bismuth 7, and cobalt 3.
It is white, fine-grained, but quite difficult to fuse.
II.—Tonca’s metal contains copper 5 parts, nickel 4, tin 1, lead 1,
iron 1, zinc 1, antimony 1. It is hard, difficult to fuse, not very
ductile, and cannot be recommended.
III.—Trabuk metal contains tin 87.5, nickel 5.5, antimony 5, bismuth 5.
IV.—Tourun-Leonard’s metal is composed of 500 parts of tin and 64 of
bell metal.
V.—Silveroid is an alloy of copper, nickel, tin, zinc, and lead.
VI.—Minargent. Copper, 100 parts; nickel, 70 parts; tungsten, 5 parts;
aluminum, 1 part.
VII.—Nickel, 23 parts; aluminum, 5 parts; copper, 5 parts; iron, 65
parts; tungsten, 4 parts.
VIII.—Argasoid. Tin, 4.035; lead, 3.544; copper, 55.780; nickel,
13.406; zinc, 23.198; iron, trace.
SOLDERS: See Solders.
«STEEL ALLOYS: See also Steel.»
«For Locomotive Cylinders.»—This mixture consists of 20 per cent steel
castings, old steel springs, etc.; 20 per cent No. 2 coke iron, and
60 per cent scrap. From this it is stated a good solid metal can be
obtained, the castings being free from honeycombing, and finishing
better than the ordinary cast-iron mixture, over which it has the
advantage of 24 per cent greater strength. Its constituents are:
Silicon, 1.51; manganese, 0.33; phosphorus, 0.65; sulphur, 0.068;
combined carbon, 0.62; graphite, 2.45.
Nickel steel is composed of nickel 36 per cent, steel 64 per cent.
Tungsten steel is crucible steel with 5 to 12 per cent tungsten.
«STEREOTYPE METAL.»
Lead 2 parts
Tin 3 parts
Bismuth 5 parts
The melting point of this alloy is 196° F. The alloy is rather costly
because of the amount of bismuth which it contains. The following
mixtures are cheaper:
I II III IV
Tin 1 3 1 2
Lead 1 5 1.5 2
Bismuth 2 8 3 5
Antimony — — — 1
«TIN ALLOYS:»
«Alloys for Dentists’ Molds and Dies.»—I.—Very hard. Tin, 16 parts;
antimony, 1 part; zinc, 1 part.
II.—Softer than the former. Tin, 8 parts; zinc, 1 part; antimony, 1
part.
III.—Very hard. Tin, 12 parts; antimony, 2 parts; copper, 1 part.
«Cadmium Alloy, about the Hardness of Zinc.»—Tin, 10 parts; antimony, 1
part; cadmium, 1 part.
«Tin-Lead.»—Tin is one of those metals which is not at all susceptible
to the action of acids, while lead, on the other hand, is very easily
attacked by them. In such alloys, consequently, used for cooking
utensils, the amount of lead must be limited, and should properly
not exceed 10 or 15 per cent; but cases have been known in which the
so-called tin contained a third part, by weight, of lead.
Alloys containing from 10 to 15 per cent of lead have a beautiful
white color, are considerably harder than pure tin, and much cheaper.
Many alloys of tin and lead are very lustrous, and are used for
stage jewelry and mirrors for reflecting the light of lamps, etc. An
especially brilliant alloy is called “Fahlun brilliants.” It is used
for stage jewelry, and consists of 29 parts of tin and 19 of lead. It
is poured into molds faceted in the same way as diamonds, and when seen
by artificial light, the effect is that of diamonds. Other alloys of
tin and lead are employed in the manufacture of toys. These must fill
the molds well, and must also be cheap, and therefore as much as 50 per
cent of lead is used. Toys can also be made from type metal, which is
even cheaper than the alloys of tin and lead, but has the disadvantage
of readily breaking if the articles are sharply bent. The alloys of tin
and lead give very good castings, if sharp iron or brass molds are used.
Lead 19 parts
Tin 29 parts
This alloy is very bright and possesses a permanent sheen. It is
well adapted for the making of artificial gems for stage use. It is
customary in carrying out the process to start with two parts of tin
and one part of lead. Tin is added until a sample drop which is allowed
to fall upon an iron plate forms a mirror. The artificial gems are
produced by {78} dipping into the molten alloy pieces of glass cut to
the proper shape. The tin coating of metal which adheres to the glass
cools rapidly and adheres tenaciously. Outwardly these artificial gems
appear rough and gray, but inwardly they are highly reflective and
quite deceptive when seen in artificial light.
If the reflective surfaces be coated with red, blue, or green aniline,
various colored effects can be obtained. Instead of fragile glass the
gems may be produced by means of well-polished pieces of steel or
bronze.
«Other Tin-Lead Alloys.»—Percentage of lead and specific gravity.
P. C. S. G.
0 7.290
1 7.316
2 7.342
3 7.369
4 7.396
5 7.423
6 7.450
7 7.477
8 7.505
9 7.533
10 7.562
11 7.590
12 7.619
13 7.648
14 7.677
15 7.706
16 7.735
17 7.764
18 7.794
19 7.824
20 7.854
21 7.885
22 7.916
23 7.947
24 7.978
25 8.009
26 8.041
27 8.073
28 8.105
29 8.137
30 8.169
31 8.202
32 8.235
33 8.268
34 8.302
35 8.336
36 8.379
37 8.405
38 8.440
39 8.476
40 8.512
41 8.548
42 8.584
43 8.621
44 8.658
45 8.695
46 8.732
47 8.770
48 8.808
49 8.846
50 8.884
60 9.299
70 9.736
80 10.225
90 10.767
100 11.370
«Tin Statuettes, Buttons, etc.»—
I.—Tin 4 parts
Lead 3 parts
This is a very soft solder which sharply reproduces all details.
Another easily fusible alloy but somewhat harder, is the following:
II.—Tin. 8 parts
Lead 6 parts
Antimony 0.5 part
«Miscellaneous Tin Alloys.»—I.—Alger Metal.—Tin, 90 parts; antimony, 10
parts. This alloy is suitable as a protector.
II. Argentine Metal.—Tin, 85.5 per cent; antimony, 14.5 per cent.
III.—Ashberry metal is composed of 78 to 82 parts of tin, 16 to 20 of
antimony, 2 to 3 of copper.
IV. Quen’s Metal.—Tin, 9 parts; lead, 1 part; antimony, 1 part;
bismuth, 1 part.
«Type Metal.»—An alloy which is to serve for type metal must be readily
cast, fill out the molds sharply, and be as hard as possible. It is
difficult to satisfy all these requirements, but an alloy of antimony
and lead answers the purpose best. At the present day there are a great
many formulas for type metal in which other metals besides lead and
antimony are used, either to make the alloy more readily fusible, as
in the case of additions of bismuth, or to give it greater power of
resistance, the latter being of especial importance for types that are
subjected to constant use. Copper and iron have been recommended for
this purpose, but the fusibility of the alloys is greatly impaired by
these, and the manufacture of the types is consequently more difficult
than with an alloy of lead and antimony alone. In the following table
some alloys suitable for casting type are given:
Lead Antimony Copper Bismuth Zinc Tin Nickel
I 3 1 — — — — —
II 5 1 — — — — —
III 10 1 — — — — —
IV 10 2 — 1 — — —
V 70 18 2 — — 10 —
VI 60 20 — — — 20 —
VII 55 25 — — — 20 —
VIII 55 30 — — — 15 —
IX 100 30 8 2 — 20 8
X 6 — 4 — 90 — —
The French and English types contain a certain amount of tin, as shown
by the following analyses:
English Types French Types
I II III
Lead 69.2 61.3 55.0 55
Antimony 19.5 18.8 22.7 30
Tin 9.1 20.2 22.1 15
Copper 1.7 — — —
Ledebur gives the composition of type metal as follows:
I II III IV
Lead 75 60 80 82
Antimony 23 25 20 14.8
Tin 22 15 — 3.2
WATCHMAKERS’ ALLOYS: See Watchmakers’ Formulas.
«WHITE METALS.»
The so-called white metals are employed almost exclusively for
bearings. (See Anti-friction Metals under Alloys.) In the technology of
mechanics an accurate distinction is made between the different kinds
of metals for bearings; and they may be classed in two groups, red
brass and white metal. The {79} red-brass bearings are characterized by
great hardness and power of resistance, and are principally used for
bearings of heavily loaded and rapidly revolving axles. For the axles
of large and heavy flywheels, revolving at great speed, bearings of red
brass are preferable to white metal, though more expensive.
In recent years many machinists have found it advantageous to
substitute for the soft alloys generally in use for bearings a
metal almost as hard as the axle itself. Phosphor bronze (q. v.) is
frequently employed for this purpose, as it can easily be made as hard
as wrought or cast steel. In this case the metal is used in a thin
layer, and serves only, as it were, to fill out the small interstices
caused by wear on the axle and bearing, the latter being usually made
of some rather easily fusible alloy of lead and tin. Such bearings are
very durable, but expensive, and can only be used for large machines.
For small machines, running gently and uniformly, white-metal bearings
are preferred, and do excellent work, if the axle is not too heavily
loaded. For axles which have a high rate of revolution, bearings made
of quite hard metals are chosen, and with proper care—which, indeed,
must be given to bearings of any material—they will last for a long
time without needing repair.
WHITE METAL FOR BEARING.
──────+───────────────────────+──────+────────+──────+──────+──────+──────
│ │ Tin │Antimony│ Zinc │ Iron │ Lead │Copper
──────+───────────────────────+──────+────────+──────+──────+──────+──────
I │German, light loads │ 85.00│ 10.00 │ — — │ — — │ — — │ 5.00
II │German, light loads │ 82.00│ 11.00 │ — — │ — — │ — — │ 7.00
III │German, light loads │ 80.00│ 12.00 │ — — │ — — │ — — │ 8.00
IV │German, light loads │ 76.00│ 17.00 │ — — │ — — │ — — │ 7.00
V │German, light loads │ 3.00│ 1.00 │ 5.00│ — — │ 3.00│ 1.00
VI │German, heavy loads │ 90.00│ 8.00 │ — — │ — — │ — — │ 2.00
VII │German, heavy loads │ 86.81│ 7.62 │ — — │ — — │ — — │ 5.57
VIII │English, heavy loads │ 17.47│ — — │ 76.14│ — — │ — — │ 5.62
IX │English, medium loads │ 76.70│ 15.50 │ — — │ — — │ — — │ 7.80
X │English, medium loads │ 72.00│ 26.00 │ — — │ — — │ — — │ 2.00
XI │For mills │ 15.00│ — — │ 40.00│ — — │ 42.00│ 3.00
XII │For mills │ — — │ 1.00 │ 5.00│ — — │ 5.00│ — —
XIII │For mills │ — — │ 1.00 │ 10.00│ — — │ 2.00│ — —
XIV │Heavy axles │ 72.70│ 18.20 │ — — │ — — │ — — │ 9.10
XV │Heavy axles │ 38.00│ 6.00 │ 47.00│ — — │ 4.00│ 1.00
XVI │Rapidly revolving axles│ 17.00│ 77.00 │ — — │ — — │ — — │ 6.00
XVII │Very hard metal │ 55.00│ — — │ — — │ 70.00│ — — │ 2.50
XVIII │Very hard metal │ 12.00│ 82.00 │ 2.00│ — — │ — — │ 4.00
XIX │Cheap metal │ 2.00│ 2.00 │ 88.00│ — — │ — — │ 8.00
XX │Cheap metal │ 1.50│ 1.50 │ 90.00│ — — │ — — │ 7.00
──────+───────────────────────+──────+────────+──────+──────+──────+──────
Other white bearing metals are:
XXI.—Tin, 8.5; antimony, 10; copper, 5 parts.
XXII.—Tin, 42; antimony, 16; lead, 42 parts.
XXIII.—Tin, 72; antimony, 26; copper, 2 parts.
XXIV.—Tin, 81; antimony, 12.5; copper, 6.5 parts.
«White Metals Based on Copper.»—
I.—Copper, 65 parts; arsenic, 55 parts.
II.—Copper, 64 parts; arsenic, 50 parts.
III.—Copper, 10 parts; zinc, 20 parts; nickel, 30 parts.
IV.—Nickel, 70 parts; copper, 30 parts; zinc, 20 parts.
V.—Nickel, 60 parts; copper, 30 parts; zinc, 30 parts.
VI.—Copper, 8 parts; nickel, 4 parts; zinc, 4 parts.
VII.—Copper, 10 parts; nickel, 5 parts; zinc, 5 parts.
VIII.—Copper, 8 parts; nickel, 3 parts; zinc, 4 parts.
IX.—Copper, 50 parts; nickel, 25 parts; zinc, 25 parts.
X.—Copper, 55 parts; nickel, 24 parts; zinc, 21 parts.
XI.—Copper, 55 parts; nickel, 24 parts; zinc, 16 parts; iron, 2 parts;
tin, 3 parts.
IX, X, and XI are suitable for tableware.
XII.—Copper, 67 parts, and arsenic, 53 parts.
XIII.—Copper, 63 parts, and arsenic, 57 parts.
XII and XIII are bright gray, unaffected by the temperature of boiling
water; they are fusible at red heat.
«White Metals Based on Platinum.»—
I.—Platinum, 1 part; copper, 4 parts; or platinum, 1 1/2 parts;
copper, 3 1/2 parts.
II.—Platinum, 10 parts; tin, 90 parts; or platinum, 8 parts; tin, 92
parts.
III.—Platinum, 7 parts; copper, 13 parts; tin, 80 parts.
IV.—Platinum, 2 parts; steel, 98 parts.
V.—Platinum, 2.5 parts; steel, 97.5 parts.
IV and V are for gun metal.
«Miscellaneous White-Metal Alloys.»—
I.—For lining cross-head slides: Lead, 65 parts; antimony, 25 parts;
copper, 10 parts. Some object to white metal containing lead or zinc.
It has been found, however, that lead and zinc have properties of great
use in these alloys.
II.—Tin, 85 parts; antimony, 7 1/2 parts; copper, 7 1/2 parts.
III.—Tin, 90 parts; copper, 3 parts; antimony, 7 parts. {80}
«ZINC ALLOYS:»
«Bidery Metal.»—This is sometimes composed of 31 parts of zinc, 2
parts of copper, and 2 parts of lead; the whole is melted on a layer
of rosin or wax to avoid oxidation. This metal is very resistive; it
does not oxidize in air or moisture. It takes its name from the town of
Bider, near Hyderabad (India), where it was prepared for the first time
industrially for the manufacture of different utensils.
Other compositions of Indian Bidery metal (frequently imitated in
England) are about as follows:
P.C. P.C. P.C.
Copper 3.5 11.4 16
Zinc 93.4 84.3 112
Tin — 1.4 2
Lead 3.1 2.9 4
Erhardt recommends the following as being both ductile and hard:
Zinc 89 to 93
Tin 9 to 6
Lead 2 to 4
Copper 2 to 4
The tin is first melted, and the lead, zinc, and copper added
successively.
«Zinc-Nickel.»—Zinc, 90 parts; nickel, 10 parts. Used in powder form
for painting and cloth printing purposes.
«Platine for Dress Buttons.»—Copper, 43 parts; zinc, 57 parts.
«UNCLASSIFIED ALLOYS:»
«Alloys for Drawing Colors on Steel.»—Alloys of various composition are
successfully used for drawing colors on steel. To draw to a straw color
use 2 parts of lead and 1 part of tin, and melt in an iron ladle. Hold
the steel piece to be drawn in the alloy as it melts and it will turn
to straw color. This mixture melts at a temperature of about 437° F.
For darker yellow use 9 parts of lead to 4 parts of tin, which melts at
458° F. For purple, use 3 parts of lead to 1 part of tin, the melting
temperature being 482° F. For violet, use 9 parts of lead to 2 parts of
tin, which melts at 494° F. Lead without any alloy will draw steel to a
dark blue. The above apply to steel only since iron requires a somewhat
greater heat and is more or less uncertain in handling.