nerfs_ (of sinews), 5 parts; fat drying oil, 5 parts; {25} powdered
turpentine, 3 parts; essence of turpentine, 2 parts. Dissolve the
glue _de nerfs_ on the water bath, add all the other substances, and
triturate intimately.
XV.—Copal varnish, 15 parts; powdered turpentine, 3 parts; essence
of turpentine, 2 parts; powdered fish glue, 3 parts; iron filings, 3
parts; ocher, 10 parts.
XVI.—To make a cement for cast iron, take 16 ounces cast-iron borings;
2 ounces sal ammoniac, and 1 ounce sulphur. Mix well and keep dry.
When ready to use take 1 part of this powder to 20 parts of cast-iron
borings and mix thoroughly into a stiff paste, adding a little water.
XVII.—Litharge 2 parts
Boiled linseed oil 2 parts
White lead 1 part
Copal 1 part
Heat together until of a uniform consistence and apply warm.
XVIII.—A cement for iron which is said to be perfectly waterproof and
fireproof is made by working up a mixture of equal weights of red lead
and litharge with glycerine till the mass is perfectly homogeneous and
has the consistency of a glazier’s putty. This cement is said to answer
well, even for very large iron vessels, and to be unsurpassable for
stopping up cracks in large iron pans of steam pipes.
«Cement for Metal, Glass, and Porcelain.»—A soft alloy is prepared by
mixing from 30 to 36 parts of copper precipitated in the form of a
fine brown powder, with sulphuric acid of a specific gravity of 1.85
in a cast-iron or porcelain mortar and incorporating by stirring with
75 parts of mercury, the acid being afterwards removed by washing with
water. In from 10 to 14 hours the amalgam becomes harder than tin, but
when heated to 692° F., it can be kneaded like wax. In this condition
it is applied to the surface to be cemented, and will fix them firmly
together on cooling.
Dissolve 1 drachm of gum mastic in 3 drachms of spirits of wine. In
a separate vessel containing water soak 3 drachms of isinglass. When
thoroughly soaked take it out of the water and put it into 5 drachms
of spirits of wine. Take a piece of gum ammoniacum the size of a large
pea and grind it up finely with a little spirits of wine and isinglass
until it has dissolved. Then mix the whole together with sufficient
heat. It will be found most convenient to place the vessel on a
hot-water bath. Keep this cement in a bottle closely stoppered, and
when it is to be used, place it in hot water until dissolved.
«Cements for Fastening Porcelain to Metal.»—I.—Mix equal parts of
alcohol (95 per cent) and water, and make a paste by incorporating
the liquid with 300 parts of finely pulverized chalk and 250 parts of
starch.
II.—Mix finely powdered burned lime, 300 parts, with powdered starch,
250 parts, and moisten the mixture with a compound of equal parts of
water and alcohol of 95 per cent until a paste results.
III.—Cement or plaster can be used if the surfaces are sufficiently
large; cement is the better article when the object may be exposed
to moisture or subjected to much pressure. A process which can be
recommended consists in mingling equal weights of chalk, brickdust,
clay, and Romain cement. These materials, pulverized and sifted are
incorporated with linseed oil in the proportion of half a kilo of oil
to 3 kilos of the mingled powder. The Romain or Romanic cement is so
designated from the district in France where the calcareous stone from
which it is prepared is found in considerable quantity. Although its
adhesive qualities are unquestioned, there are undoubtedly American
cements equally as good.
IV.—Acetate of lead, 46 1/2 parts by weight; alum, 46 1/2 parts by
weight; gum arabic, 76 parts by weight; flour, 500 parts by weight;
water, 2,000 parts by weight. Dissolve the acetate of lead and the alum
in a little water; on the other hand dissolve the gum arabic in water
by pouring, for instance, the 2 liters of boiling water on the gum
arabic reduced to powder. When the gum has dissolved, add the flour,
put all on the fire, and stir well with a piece of wood; then add the
solution of acetate of lead and the alum; agitate well so as to prevent
any lumps from forming; retire from the fire before allowing to boil.
This glue is used cold, does not peel off, and is excellent to make
wood, glass, cardboard, etc. adhere to metals.
«Cement for Leather and Iron.»—To face a cast-iron pulley with leather
apply acetic acid to the face of the pulley with a brush, which will
roughen it by rusting, and then when dry apply a cement made of 1 pound
of fish glue and 1/2 pound of common glue, melted in a mixture of
alcohol and water. The leather should then be placed on the pulley and
dried under pressure. {26}
«Amber Cements.»—I.—To solder together two pieces of yellow amber,
slightly heat the parts to be united and moisten them with a solution
of caustic soda; then bring the two pieces together quickly.
II.—Dissolve in a closed bottle 75 parts of cut-up caoutchouc in 60
parts of chloroform. Add 15 parts of mastic and let the mixture stand
in the cold until all has dissolved.
III.—Moisten the pieces to be joined with caustic potash and press
them together when warm. The union is so perfect that no trace of the
juncture is visible. A concentrated alcoholic solution of the rosin
over the amber, soluble in alcohol, is also employed for this purpose.
Another medium is a solution of hard and very finely powdered copal in
pure sulphuric ether. Coat both fractures, previously well cleaned,
with this solution and endeavor to combine them intimately by tying or
pressing.
IV.—In 30 parts by weight of copal dissolve 30 parts by weight of
alumina by means of a water bath. Bathe the surface to be cemented with
this gelatinous liquid, but very slightly. Unite the fractures and
press them together firmly until the mixture is dry.
«Acid-Proof Cements for Stoneware and Glass.»—I.—Mix with the aid of
heat equal weights of pitch, rosin, and plaster of Paris.
II.—Mix silicate of soda to a paste with ground glass.
III.—Mix boiled oil to a paste with china clay.
IV.—Mix coal tar to a paste with pipe clay.
V.—Mix boiled oil to a paste with quicklime.
VI.—Mix with the aid of heat: Sulphur, 100 pounds; tallow, 2 pounds;
rosin, 2 pounds. Thicken with ground glass.
VII.—Mix with the aid of heat: Rosin, 2 pounds; sulphur, 2 pounds;
brickdust, 4 pounds.
VIII.—Mix with the aid of heat 2 pounds of india rubber and 4 pounds of
oiled oil. Thicken with 12 pounds of pipe clay.
IX.—Fuse 100 pounds of india rubber with 7 pounds of tallow. Then make
to a paste with dry slaked lime and finally add 20 pounds of red lead.
X.—Mix with the aid of heat: Rosin, 24 pounds; red ocher, 8 pounds;
boiled oil, 2 pounds; plaster of Paris, 4 pounds.
«Acid-Proof Cement for Wood, Metals, etc.»—
I.—Powdered asbestos 2 parts
Ground baryta 1 part
Sodium water-glass solution 2 parts
Mix.
II.—To withstand hot nitric acid the following is used:
Sodium water-glass solution 2 parts
Sand 1 part
Asbestos 1 part
Mix.
III.—Asbestos 2 parts
Sulphate of barium 3 parts
Silicate of sodium 2 parts
By mixing these ingredients a cement strong enough to resist the
strongest nitric acid will be obtained.
IV.—If hot acids are dealt with, the following mixture will be found to
possess still more resistant powers:
Silicate of sodium (50° Baumé) 2 parts
Fine sand 1 part
Asbestos 1 part
Both these cements take a few hours to set. If the cement is wanted to
set at once, use silicate of potassium, instead of silicate of sodium.
This mixture will be instantly effective and possesses the same power
of resistance as the other.
«Directions for Repairing Broken Glass, Porcelain, Bric-à-Brac.»—Broken
glass, china, bric-à-brac, and picture frames, not to name casts,
require each a different cement—in fact, several different cements.
Glass may be beautifully mended to look at, but seldom so as to be
safely used. For clear glass the best cement is isinglass dissolved in
gin. Put 2 ounces of isinglass in a clean, wide-mouthed bottle, add
half a pint of gin, and set in the sun until dissolved. Shake well
every day, and before using strain through double lawn, squeezing very
gently.
Spread a white cloth over the mending table and supply it with plenty
of clean linen rags, strong rubber bands, and narrow white tape,
also a basin of tepid water and a clean soft towel. Wash the broken
glass very clean, especially along the break, but take care not to
chip it further. Wet both broken edges well with the glue, using a
camel’s-hair pencil. Fit the break to a nicety, then slip on rubber
bands length- and cross-wise, every way they will hold. If they will
not hold true as upon a stemmed {27} thing, a vase or jug or scent
bottle, string half a dozen bands of the same size and strength upon a
bit of tape, and tie the tape about neck or base before beginning the
gluing. After the parts are joined slip another tape through the same
bands and tie it above the fracture; thus with all their strength the
bands pull the break together. The bands can be used thus on casts of
china—in fact, to hold anything mendable. In glass mending the greater
the pressure the better—if only it stops short of the breaking point.
Properly made the isinglass cement is as clear as water. When the
pieces fit true one on the other the break should be hardly visible, if
the pressure has been great enough to force out the tiny bubbles, which
otherwise refract the light and make the line of cleavage distressingly
apparent. Mended glass may be used to hold dry things—as rose leaves,
sachets, violet powder, even candies and fruits. But it will not bear
to have any sort of liquid left standing in it, nor to be washed beyond
a quick rinsing in tepid water. In wiping always use a very soft towel,
and pat the vessel dry with due regard to its infirmities.
Mend a lamp loose in the collar with sifted plaster of Paris mixed to a
very soft paste with beaten white of egg. Have everything ready before
wetting up the plaster, and work quickly so it may set in place. With
several lamps to mend wet enough plaster for one at a time. It takes
less than 5 minutes to set, and is utterly worthless if one tries
working it over. Metal work apart from the glass needs the soldering
iron. Dust the break well with powdered rosin, tie the parts firmly
together, lay the stick of solder above the break, and fetch the iron
down on it lightly but firmly. When the solder cools, remove the melted
rosin with a cloth dipped in alcohol.
Since breakables have so unhappy a knack of fracturing themselves in
such fashion they cannot possibly stand upright, one needs a sand box.
It is only a box of handy size with 8 inches of clean, coarse sand in
the bottom. Along with it there should be some small leaden weights,
with rings cast in them, running from an ounce to a quarter pound. Two
of each weight are needed. In use, tapes are tied to the rings, and
the pair of weights swung outside the edges of the box, so as to press
in place the upper part of a broken thing to which the tapes have been
fastened.
Set broken platters on edge in the sand box with the break up. The
sand will hold them firm, and the broken bit can be slapped on. It
is the same with plates and saucers. None of these commonly requires
weighting. But very fine pieces where an invisible seam is wanted
should be held firm until partly set, then have the pair of heaviest
weights accurately balanced across the broken piece. The weights are
also very useful to prop and stay topheavy articles and balance them so
they shall not get out of kilter. A cup broken, as is so common with
cups, can have the tape passed around it, crossing inside the handle,
then be set firmly in the sand, face down, and be held by the hanging
weights pulling one against the other.
The most dependable cement for china is pure white lead, ground
in linseed oil, so thick it will barely spread smoothly with a
knife. Given time enough to harden (some 3 months), it makes a seam
practically indestructible. The objection to it is that it always shows
in a staring white line. A better cement for fine china is white of egg
and plaster. Sift the plaster three times and tie a generous pinch of
it loosely in mosquito netting. Then beat the egg until it will stick
to the plaster. Have the broken edge very clean, cover both with the
beaten egg, dust well with the plaster, fit together at once, tie,
using rubber bands if possible, wrap loosely in very soft tissue paper,
and bury head and ears in the sand box, taking care that the break lies
so that the sand will hold it together. Leave in the box 24 hours.
After a week the superfluous plaster may be gently scraped away.
«General Formulas for Cements for Repairing Porcelain, Glassware,
Crockery, Plaster, and Meerschaum.»—I.—An excellent cement for joining
broken crockery and similar small articles can be made by melting 4 or
5 parts of rosin (or, better still, gum mastic) with 1 part of beeswax
in an iron spoon or similar vessel. Apply while hot. It will not stand
great heat.
II.—An excellent cement for porcelain and stoneware is obtained by
mixing 20 parts of fish glue with an equal weight of crystallizable
acetic acid and evaporate the mixture carefully to a syrupy consistency
so that it forms a gelatinous mass on cooling. For use the cement thus
obtained is made liquid again by heating and applied to the fracture
with a brush. The pieces should now be pressed firmly together, by
winding a twine tightly around them, until the cement has hardened.
III.—For luting vessels made of glass, {28} porcelain, etc., which
are to be used to hold strong acids, a mixture of asbestos powder,
water glass, and an indifferent powder (permanent white, sand, etc.)
is recommended. To begin with, asbestos powder is made into a pulp
with three or four times the quantity (weight) of a solution of soda
water glass (of 30° B.). The same is exceedingly fat and plastic, but
is not very well suited for working, as it shrinks too much and cracks
when drying. By an addition of fine writing sand of the same weight
as the asbestos used, the mass can be made less fat, so as to obviate
shrinking, without detracting from the plasticity. Small vessels were
molded from it and dried in the air, to be tested afterwards. Put in
water, the hardened mass becomes soft again and falls apart. Brought
into contact, however, with very strong mineral acids, it becomes even
firmer and withstands the liquid perfectly. Concentrated nitric acid
was kept in such small vessels without the mass being visibly attacked
or anything penetrating it. The action of the acid manifestly has the
effect that silicic acid is set free from the water glass in excess,
which clogs up the pores entirely and contributes to the lutation.
Later on, the mass cannot be dissolved by pure water any more. The mass
is also highly fireproof. One of the molded bodies can be kept glowing
in a Bunsen gas flame for about half a day after treatment with acid,
without slagging in the least. For many purposes it ought to be welcome
to have such a mass at hand. It cannot be kept ready for use, however,
as it hardens a few hours after being prepared; if potash water glass
is used, instead of the soda composition, this induration takes place
still more quickly.
IV.—Cement for Glass, Porcelain, etc.—
Isinglass (fish glue) 50 parts
Gum ammoniac 4 parts
Gum mastic 2 parts
Alcohol, 95 per cent 10 parts
Water, q. s.
Soak the isinglass in cold water over night, or until it has become
swollen and soft throughout. In the morning throw off any superfluous
fluid and throw the isinglass on a clean towel or other coarse cloth,
and hang it up in such a way that any free residual water will drain
away. Upon doing this thoroughly depends, in a great measure, the
strength of the cement. When the gelatin has become thoroughly drained
put it into a flask or other container, place it in the water bath and
heat carefully until it becomes fluid, being careful not to let it come
to a boil, as this injures its adhesive properties (the same may be
said in regard to glues and gelatins of all kinds). Dissolve the gums
in the alcohol and add the solution to the gelatin after removing the
same from the water bath, and letting it cool down to about 160° F.
Stir well together or mix by agitation.
The following precautions must be observed: 1. Both surfaces to be
joined must be absolutely clean, free from dust, dirt, grease, etc.
2. Where the cement is one that requires the application of heat
before use, the objects to be united should also _be heated to a point
at least as high as the melting point of the cement_. Otherwise, the
cement on application is chilled and consequently fails to make a
lasting joint. 3. The thinner the layer of cement the stronger the
joint; avoid, therefore, using too much of the binding material. Cover
both surfaces to be united, coapt them exactly, and press together as
closely as possible. In this manner the thinnest possible layer is
secured. 4. Bind the parts securely together, and let remain without
loosening or attempting to use the article for 2 or 3 days or longer. A
liquid cement acquires its full strength only after evaporation of the
fluids used as solvents, and this can occur only from the infinitesimal
line of exposed surface.
V.—Liquid Porcelain Cement.—Fish glue, 20 parts; glass acetic acid, 20
parts; heat together until the mass gelatinizes on cooling.
VI.—Take 1 ounce of Russian isinglass, cut in small pieces, and bruise
well; then add 6 ounces of warm water, and leave it in a warm place
for from 24 to 48 hours. Evaporate the resulting solution to about 3
ounces. Next dissolve 1/2 ounce of mastic in 4 ounces of alcohol,
and add the mastic solution to the isinglass in small quantities at a
time, continuing the heat and stirring well. While still hot strain the
liquid through muslin.
VII.—For optical glasses, Canada balsam is employed, the two pieces
being firmly pressed together. After a while, especially by humidity,
punctures will form, and the glass is separated by a mist of varying
reflexes, while in certain climates the heat will melt the balsam. For
all other glass articles which require only simple treatment, such as
knobs of covers, plates, etc., silicate of potash is excellent.
VIII.—Glass Cement.—Dissolve in 150 parts of acetic acid of 96 per
cent, 100 {29} parts of gelatin by the use of heat, and add ammonium
bichromate, 5 parts. This glue must be kept away from the light.
IX.—White glue 10 parts
Potassium bichromate 2 parts
Water 100 parts
The glue is dissolved in a portion of the water by the aid of heat,
the bichromate in the remainder, and the liquids mixed, the mixing
being done in a feebly lighted place, and the mixture is then kept
in the dark. It is applied in feeble light, being reliquefied by
gentle heat, and the glass, the fractured pieces being tightly clamped
together, is then exposed to a strong light for some time. By this
exposure the cement becomes insoluble. This is waterproof cement for
glass.
X.—Diamond Glass Cement.—Dissolve 100 parts of fish glue in 150 parts
of 90 per cent alcohol and add, with constant stirring, 200 parts of
powdered rosin. This cement must be preserved in absolutely tight
bottles, as it solidifies very quickly.
XI.—To unite objects of crystal dissolve 8 parts of caoutchouc and 100
parts of gum mastic in 600 parts of chloroform. Set aside, hermetically
closed, for 8 days; then apply with a brush, cold.
XII.—To make a transparent cement for glass, digest together for a week
in the cold 1 ounce of india rubber, 67 ounces of chloroform, and 40
ounces of mastic.
XIII.—A mixture of traumaticin, a solution of caoutchouc in chloroform,
and a concentrated solution of water glass make a capital cement for
uniting articles of glass. Not only is the joint very strong, but it
is transparent. Neither changes of temperature nor moisture affect the
cement.
XIV.—A transparent cement for porcelain is prepared by dissolving 75
parts of india rubber, cut into small pieces, in a bottle containing
60 parts chloroform; to this add 15 parts green mastic. Let the
bottle stand in the cold until the ingredients have become thoroughly
dissolved.
XV.—Some preparations resist the action of heat and moisture a short
time, but generally yield very quickly. The following cement for glass
has proven most resistant to liquids and heat:
Silver litharge 1,000 parts
White lead 50 parts
Boiled linseed oil 3 parts
Copal varnish 1 part
Mix the lead and litharge thoroughly, and the oil and copal in the
same manner, and preserve separately. When needed for use, mix in
the proportions indicated (150 parts of the powder to 4 parts of the
liquid) and knead well together. Apply to the edges of the glass, bind
the broken parts together, and let stand for from 24 to 48 hours.
XVI.—To reunite plaster articles dissolve small pieces of celluloid in
ether; in a quarter of an hour decant, and use the pasty deposit which
remains for smearing the edges of the articles. It dries rapidly and is
insoluble in water.
XVII.—To Mend Wedgwood Mortars.—It is easy enough to mend mortars so
that they may be used for making emulsions and other light work which
does not tax their strength too much. But a mended mortar will hardly
be able to stand the force required for powdering hard substances. A
good cement for mending mortars is the following:
_a._—Glass flour elutriated 10 parts
Fluorspar, powdered and elutriated 20 parts
Silicate of soda 60 parts
Both glass and fluorspar must be in the finest possible condition,
which is best done by shaking each in fine powder, with water allowing
the coarser particles to deposit, and then to pour off the remainder,
which holds the finest particles in suspension. The mixture must be
made very rapidly by quick stirring, and when thoroughly mixed must be
at once applied. This is said to yield an excellent cement.
_b._—Freshly burnt plaster of Paris 5 parts
Freshly burnt lime 1 part
White of egg, sufficient.
Reduce the first two ingredients to a very fine powder and mix them
well; moisten the two surfaces to be united with a small quantity of
white of egg to make them adhesive; then mix the powder very rapidly
with the white of egg and apply the mixture to the broken surfaces. If
they are large, two persons should do this, each applying the cement
to one portion. The pieces are then firmly pressed together and left
undisturbed for several days. The less cement is used the better will
the articles hold together.
_c._—If there is no objection to dark-colored cement, the very best
that can be used is probably marine glue. This is made thus: Ten parts
of caoutchouc or india rubber are dissolved in 120 parts of benzine
or petroleum naphtha, with {30} the aid of a gentle heat. When the
solution is complete, which sometimes requires from 10 to 14 days,
20 parts of asphalt are melted in an iron vessel and the caoutchouc
solution is poured in very slowly in a fine stream and under continued
heating, until the mass has become homogeneous and nearly all the
solvent has been driven off. It is then poured out and cast into
greased tin molds. It forms dark brown or black cakes, which are very
hard to break. This cement requires considerable heat to melt it; and
to prevent it from being burnt it is best to heat a capsule containing
a piece of it first on a water bath until the cake softens and begins
to be liquid. It is then carefully wiped dry and heated over a naked
flame, under constant stirring, up to about 300° F. The edges of the
article to be mended should, if possible, also be heated to at least
212° F., so as to permit the cement to be applied at leisure and with
care. The thinner the cement is applied the better it binds.