John Phin.

The workshop companion. A collection of useful and reliable recipes, rules, processes, methods, wrinkles, and practical hints for the household and the shop online

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the acids of fruit, etc. It is also soluble in water containing
an excess of carbonic acid, and therefore dissolves rapidly in
the ordinary "soda" water that is so generally sold as a
beverage, for this fluid, in its pure state, consists solely of
water holding a large amount of carbonic acid in solution.
Consequently bottles and glasses of this liquid should not be
placed where there is any danger of spilling it on mantel
pieces, table i^ps, etc., PS it will infallibly destroy the ex-
quisite polish upon which the beauty of such articles of
furniture depends.

Finely carved articles of marble, when exposed to the rain
of our northern climates, are apt to suffer corrosion, and the
delicate tracery of the sculptor is soon lost. Therefore,
while marble answered very well in the comparatively dry
climates of Greece and Egypt, it is unsuited for statues, etc. ,
exposed to the open air, in England and America, the rainfall
in these countries being very great, and the moisture heavily
charged with carbonic and sulphurous acids.

In cleaning marble ornaments, etc., great care must be ex-
ercised .to use nothing corrosive like acids, chlorides, or
metallic salts, such as are usually recommended for removing
stains of inks and dyes from wood and textile fabrics. When
marble has been stained by ink or vegetable coloring matter,
the only way to remove it is to apply warm water abundantly
and for a long time. If the marble is very compact, and the
stain consequently quite superficial, the article may be
scraped and repolished, but of course this is applicable only
to objects which have plane surfaces, or those Avith simple
curves. Elaborately carved or sculptured objects could not
be so treated.

Greasy stains may be removed by covering them with a
paste of chalk and potash or soda. 'The alkali will convert
the grease into soap, which will be gradually absorbed by the
chalk and thus removed. In such cases, however, the stains,
especially if old, may require a long time and several repeti-
tions of the process. Alkalies (potash, soda and ammonia)
may be applied to marble without injuring it, and any stains
which they can remove may be taken out by their means.

garble is easily worked either on the bench or in the latuo



92 THE WORKSHOP COMPANION.

In the latter case, however, great care must be taken to avoid
anything like a heavy cut, since marble is so rigid and brittle
that if the cut be heavy the article is apt to be broken. The
only tool that can be used is a steel point, tempered to a
straw color. The tool requires frequent grinding, and when
it gets broad it must be forged over again, as a flat tool will
not turn marble at all.

For working and finishing marble on the bench the follow-
ing is the process : After the marble is sawn into slab, the
first operation is to grind it down with a flat coarse sandstone
and water, or with an iron plate, fed with fine sand and water,
until all the marks of the saw are perfectly removed ;
secondly, a fine sandstone is used with water until the
marks made by the first stone are removed; thirdly, a
finer sandstone is applied to work out the marks of the
former ; fourthly, pumice stone with water, and fifthly, snake
stone is used, and this last finishes what is called the
grounding.

Next comes the polishing, which is principally performed
with rollers of woolen cloth or list made to the size of about
three inches diameter. As the sixth process, a rubber is
charged with flour emery and a moderate degree of moisture ;
this rubber is worked uniformly over every part until the
marble acquires a kind of greasy polish; seventh ly, the work
is completed with a similar roll of cloth charged with putty
powder and water. Some prefer, as the polisher, an old
cotton stocking not made into a rubber, and in some few of the
more delicate works crocus is used intermediately between
the emery and the putty powder. It is necessary to wash
the marble after each operation, so that not a particle of the
previous polishing material may remain, otherwise the work
will be scratched.

The dull parts of sculpture are finished in four different
manners, or rather the complete process of smoothing is dis-
continued at various stages so as to form four gradations,
which may be described as follows :

First. The marble is sometimes left from the long and
very slender statuary's chisel, the reverse end of which is
formed with a sharp circular edge or ridge, just like a hollow
centre, in order that the metal hammer, which is of soft iron,
tin or zinc, may be slightly indented by the chisel, so as to
avoid its glancing off ; the chisel marks leave the surface



THE WOKKSHOP COMPANION. 93

somewhat rough and matted, intermediate between the
granular and crystalline character.

Secondly. For surfaces somewhat smoother, rasps are used
to remove the ridges left by the chisel ; the rasps leave a
striated or lined effect suitable for draperies, and which is
made more or less regular according to the uniformity of the
strokes, or the reverse.

Thirdly. Files are employed for still smoother surfaces of
the same character ; and it is to be observed that the files
and rasps are generally curved at the ends, to adapt them to
the curvilinear forms of the sculpture.

Fourthly. For the smoothest of the dull or unpolished
surfaces, the faint marks left by the file are rubbed out with
Trent sand or silver sand and water, applied by means of a
stick of deal cut to a point, and rubbed all over the work in
little irregular circles, as a child would scribble on a slate,
and if the end of the stick is covered with two or three
thicknesses of cloth the marble receives a still rounder or
softer effect than from the naked stick, for which the cabbage
wood or partridge wood is sometimes used, and the end of the
stick is slightly bruised, so that the fibres of the wood may
assume the character of the stiff brush, known by artists as a
scrub."

Mr. Thomas Smith tells us that he has successfully copied
the minute roughness or granulation of the skin, by a kind of
etching which he was induced to try, by imagining that ho
could trace such a process to have been used in some of the-
most perfect of the ancient marbles that had not been exposed
to the open air. The w r ork having been smoothed with sand,
as above, he takes a hard, stubby brush and therewith dots
the marble with muriatic acid, and which quickly, yet par-
tially, dissolves the surface. The strength of the acid, which
must not be excessive, is tested upon a piece of waste marble;
the brush is hastily dipped in the acid, applied to the work,
quickly rinsed in water, and then used for removing the acid
from the marble. It is obvious the process calls for a certain
admixture of dexterity and boldness, and sometimes requires
several repetitions, the process occupying only a few minutes
each time.

Fifthly. The bright parts of sculpture. Few of the works
in sculpture are polished, and such as are, are required in the
first instance to pass through the four stages already explained



94 THE WORKSHOP COMPANION.

for producing the smooth but dull surface ; after which,
slender square pieces of the second gritstone and of snake-
stone are used with water as a pencil, and then fine emery
and putty powder on sticks of wood ; but the work is exceed-
ingly tedious, and requires very great care, that the artistical
character of the work, and any keen edges that may be re-
quired are not lost in the polishing.

Metals Polishing.

Metals are polished either by burnishing or buffing. The
process ot burnishing consists in rubbing down all the minute
roughnesses by means of a highly polished steel or agate
tool none of the metal being removed.

The action of the burnisher appears to depend upon two
circumstances ; first, that the harder the material to be
polished the greater lustre it will receive ; the burnisher is,
therefore, commonly made of hardened steel, which exceeds in
hardness nearly every metallic body. And secondly, its
action depends on the intimacy of the contact betwixt the
burnisher and the work ; and the pressure of the brightened
burnisher being, in reality, from its rounded or elliptical
section, exerted upon only one mathematical line or point of
the work at a time, it acts with great pressure and in a man-
ner distinctly analogous to the steel die used in making coin;
in which latter case the dull but smooth blank becomes in-
stantly the bright and lustrous coin, in virtue of the intimate
contact produced in the coining press between the entire
surface of the blank and that of the highly polished die.

It by no means follows, however, that the burnisher will
produce highly finished surfaces, unless they have been pre-
viously rendered smooth, and proper for the application of
this instrument, as a rough surface, having any file marks or
scratches, will exhibit the original defects, notwithstanding
that they may be glossed over with the burnisher which
follows every irregularity ; and excessive pressure, which
might be expected to correct the evil as in coining, only fills
the work with furrows, or produces an irregular indented
surface, which by workmen is said to be/V// of uttws.

Therefore, the greater the degree of excellence that is re-
quired in burnished works, the more carefully should they
be smoothed before the application of the burnisher, and this
s|)ou]4 also be cleaned on a buff stick with crocus, inv



THE WOBKSBOP COMPANION. 95

mediately before use ; and it should in general be applied
with the least degree of friction that will suffice. Cutlers
mostly consider that burnishers for steel are best rubbed on
a buff stick Avith the finest flour emery ; for silver, however,
they polish the burnisher with crocus as usual. Most of the
metals, previously to their being burnished, are rubbed with
oil to lessen the risk of tearing or scratching them, but for
gold and silver the burnisher is commonly used dry, unless
soap and water or skimmed milk are employed ; and for
brass furniture, beer or water, with or without a little vinegar,
is preferred for lubricating the burnisher.

Buffing is performed by rubbing the metal with soft leather,
which has been charged with very fine polishing powder.
The rubbing is sometimes done by hand, but more frequently
the buff is made into a wheel which revolves rapidly in a
lathe and the work is held against it.

The polishing powder that is selected must be chosen with
special reference to the metal that is to be buffed. Thus, for
steel and brass the best polishing powder is crocus or rouge,
which may be purchased of any dealer in tools, or may be
made by exposing very clean and pure crystals of sulphate of
iron to heat, according to the directions given hereafter under
the head of Polishing Powders. The hardest part of the
rouge must be selected, and great care must be taken to have
it clean and free from particles of dust and sand, which would
inevitably scratch the article to be polished and render it
necessary to again repeat #11 the previous processes of filing,
grinding, etc.

Soft metals like gold and silver may be polished with com-
paratively soft powders, such a* prepared chalk or putty
powder (oxide of tin).

When metals are to be polished in the lathe the process is
very simple. After being turned or filed smooth the article
is still further polished by means of fine emery and oil, ap-
plied with a stick, and in the case of rods or cylinders, a sort of
clamp is used so that great pressure can be brought to bear
on the part to be polished. The work must be examined
from time to time to see that all parts are brought up equally
to the greatest smoothness and freedom from scratches, and
as fast as this occurs polishing powder of finer and finer
quality is used, until the required finish is attained.

In polishing metals or anv other hard substance^ by



96 THE WOBKSHOP COMPANION.

abrasion, the great point is to bring the whole surface up
equally. A single scratch will destroy the appearance of the
finest work, and it cannot be removed except by going back
to the stage to which it corresponds, and beginning again
from that point. Thus, if in working with a smooth file we
make a scratch as deep as the cut of a bastard file, it is of
no use to try and remove this scratch with the smooth file,
we must go back, and taking a bastard file make the surface
as even as possible with it, and afterwards work forward
through fine files and polishing powders.

Mirrors.

As it is frequently convenient to be able to silver a piece of
glass for a special purpose, we quote from Faraday's work on
Chemical Manipulation, the following directions for perform-
ing this operation :

A piece of clean, smooth tinfoil, free from holes, is to be
cut to the same size as the glass and laid upon a couple of
sheets of filtering or blotting paper folded into quarters. A
little mercury is to be placed on the foil, and rubbed over it
with a hare's foot, or with a ball of cotton slightly greased
with tallow, until the whole of the upper surface of the leaf
be amalgamated and bright. More mercury is then to be
added, until the quantity is such as to float over the tinfoil.
A piece of clean -writing paper, with smooth edges, is to be
laid upon the mercury, and then the glass surface, previously
well cleaned, is to be applied to the paper. The paper is to
be drawn out from between the mercury and the glass, while
a slight but steady pressure is to be applied to the latter.
As the paper recedes it carries all air and dirt with it from
between the glass and the metal, which come into perfect
contact.

The mirror is now made, and may be used for an experi-
ment ; but there is still much more mercury present than is
required to make the definite and hard amalgam of tin con-
stituting the usual reflecting surface. If it be desired to re-
move this excess, the newly-formed mirror must be put under
the pressure of a flat board, in a slightly -inclined position,
and loaded with weights.

The success of this operation will be found to depend
chiefly upon the care exercised in cleaning the glass.

g Glass Mirrors for Optical Purposes. This is best



THE WOBKSHOP COMPANION. 97

by depositing pure silver on the glass. The light
reflected from a mirror made thus has somewhat of a yellowish
tinge, but photometric experiments show that from 25 to 30
per cent, more light is reflected than from the old mercurial
mirrors.

Where ammonium aldehyde can be obtained, there is no
doubt that this is the best and most economical process,
whether used on a large or a small scale. But those who
have not had considerable experience in the laboratory can-
not always prepare this compound.

The next best process is based upon the reduction of
metallic silver from its ammoniacal solution by salts Of tartar.
After a trial of several formulas of this kind, all of them more
or less simple, as well as efficacious, the following has been
found to yield the bast results in the shortest time.

Silvering Solution. In 1 ounce of distilled or pure rain
water, dissolve 48 grains of crystalized nitrate of silver.
Precipitate by adding strongest water of ammonia, and con-
tinue to add the ammonia drop by drop, stirring the solution
with a glass rod, until the brown precipitate is nearly, but
not quite redissolved. Filter, and add distilled water to
make 12 fluid drachms.

Reducing Solution. 1 Dissolve in 1 ounce of distilled or
very clean rain water, 12 grains of potassium and sodium
tartrate (Eochelle or Seignette salts). Boil, in a flask, and
while boiling add 2 grains crystalized nitrate of silver dis-
solved in 1 drachm of water. Continue the boiling rive or
six minutes. Let cool, filter, and add distilled water to make
12 fluid drachms.

To Silver. Provision must be made for supporting the
glass in a perfectly horizontal position at the surface of the
liquid. This is best done by cementing to the face of the
mirror three nice hooks by which it may be hung from a
temporary framework easily made out of a few sticks.

The glass to be silvered must be cleansed by immersing
it in strong nitric acid, washing in liquor potassse, and thor-
oughly rinsing with distilled water. If the glass has had
mercurial amalgam on it, it will probably be necessary to
clean the back with rouge. On having this surface per-
fectly, chemically clean, depends in a great measure the suc-
cess of the operation.

Having arranged the contrivance for suspending the glass



08 THE WORKSHOP COMPANION.

so that it may be at exactly the rig-lit height in the vessel
that is to receive the solution, remove this vessel and pour
into it enough of equal quantities of the two solutions to fill
it exactly to the previously ascertained level. Stir the solu-
tions so that they will become thoroughly mixed, and replace
the glass to be silvered, taking great care that the surface to
be silvered shall come in contact with the silvering fluid ex-
actly at all points. The glass plate should be rinsed carefully
before replacing, and should be put in while wet. Great care
should be taken that no air bubbles remain on the surface of
the solution, or between it and the surface to be silvered.

Now set the vessel in the sun for a few minutes, if the
weather be warm, or by the fire, if it be cold, as a tempera-
ture of 45 to 50 C. (113 to 122 Fab.) is most conducive
to the rapid deposition of a brilliant, firm and even film of
silver. The fluid in the sunlight soon becomes inky black,
gradually clearing as the silver is reduced, until when ex-
hausted it is perfectly clear. The mirror should be removed
before this point is reached, as a process of bleaching sets
up if left after the fluid is exhausted. From 20 to 80 minutes,
according to the weather, purity of chemicals, etc., is re-
quired for the entire process.

When the mirror is removed from the bath, it should be
carefully rinsed with distilled water from the wash bottle,
and laid on its edge on blotting paper to dry. When per-
fectly dry, the back should be varnished with some elastic
varnish and allowed to dry. The wires and cement can now
be removed from the face, and the glass cleaned with a little
fledget of cotton and a minute drop of nitric acid, taking
great care that the acid does not get to the edges or under
the varnish. Rinse, dry and the mirror is finished.

Silver Amalgam for Mirrors. The great objections to
mirrors coated with pure silver are the yellow character of
the reflected light, and the fact that such mirrors are apt to
be affected by sulphur. M. Lenoir has invented a process
which is said to avoid these difficulties. The glass is first
silvered by means of tartaric acid and ammoniacal nitrate of
silver, or by the process described in the preceding section,
and is then exposed to the action of a weak solution of double
cyanide of mercury and potassium. When the mercurial
solution has spread uniformly over the surface, fine zinc dust
is powdered over it, which promptly reduces the quicksilver,



THE WORKSHOP COMPANION. 99

And permits it to form a white and brilliant silver amalgam,
adhering strongly to the glass, and which is affirmed to be
free from the yellowish tint of ordinary silvered glass, and
not easily affected by sulphurous emanations.

Care of Looking Glasses. When looking glasses are ex-
posed to the direct rays of the sun or to very strong heat
from a fire the amalgam is apt to crystallize antl the mirror
loses its brilliancy. If a mirror is placed where the rays of
the sun can strike it, it should be covered in that part of the
day during which it is exposed.

The best method of cleaning looking glasses is as follows :
Take a newspaper, fold it small, dip it into a basin of clean
cold water. When thoroughly wet squeeze it out as you do
a sponge ; then rub it pretty hard all over the surface of the
glass, taking care that it is not so wet as to run down in
streams ; in fact, the paper must only be completely moist-
ened or dampened all through. Let it . rest a few minutes,
then go over the glass with a piece of fresh newspaper till it
looks clear and bright. The i asides of windows may be
cleaned in the same way ; also spectacle-glasses, lamp-glasses,
etc. White paper that has not been printed on is better;
but in the absence of that, a very old newspaper, on which
the ink -has become thoroughly dried, should be used.
Writing paper will not answer.

Nickel.

This is by far the most valuable metal that has been
brought into notice during the past few years. It has been
long familiar to chemists, and as a component of German
silver, electrum, and similar alloys, it has been in common
use, but as an unalloyed coating for other metals it has only-
been employed for about ten years.

It is hard, not easily corroded by acids, and, tinlike silver,
it is entirely unaffected by sulphur. In addition to these
valuable qualities it has one of special importance in some
cases, and that is the ease with which a nickel surface slides
over any other smooth body. Hence, for the sliding parts of
telescopes, microscopes, etc., it has come into very general
use, and it is not improbable that it will prove of great value
in the case of slide valves, pistons, etc.

Nickel is almost always applied as a coating by the electro-
plating process, for instructions in which art we must refer



100 THE WORKSHOP COMPANION.

our reaaers to any good work on the art of electro-metal-
lurgy.

A foreign journal gives the following directions for nickel
plating Avithout a battery : To a solution of five to ten per
cent, of chloride of zinc, as pure as possible, add sufficient
sulphate of nickel to produce a strong green color, and bring
to boiling in a porcelain vessel. The piece to be plated,
which must be perfectly bright and free from grease, is in-
troduced so that it touches the vessel as little as possible.
Ebullition is continued from 30 to 60 minutes, water being
added from time to time to replace that evaporated. During
ebullition nickel is precipitated in the form of a white and
brilliant coating. The boiling can be continued for hours
without sensibly increasing the thickness of this coating.
As soon as the object appears to be plated it is washed in
water containing a little chalk in suspension, and then care-
fully dried. This coating may be scoured with chalk, and is
very adherent. The chloride of zinc and also the sulphate of
nickel used must be free from metals precipitable by iron.
If during the precipitation the liquor becomes colorless,
sulphate of nickel should be added. The spent liquor may be
used again by exposing to the air until the contained iron is
precipitated, filtering and adding the zinc and nickel salts
as above. Cobalt also may be deposited in the same manner.

Noise Prevention of.

To those who carry on any operations requiring much ham-
mering or pounding, a simple means of deadening the noise
of their work is a great relief. Several methods have been
suggested, but the best are probably these :

1. Rubber cushions under the legs of the work-bench.
Chamber's Journal describes a factory where the hammering
of fifty coppersmiths was scarcely audible in the room below,
their benches having under each leg a rubber cushion.

2. Kegs of sand or sawdust applied in the same way. A
few inches of. sand or sawdust is first poured into each keg ;
on this is laid a board or block upon which the leg rests,
and round the leg and block is poured fine dry sand or saw-
dust. Not only all noise, but all vibration and shock, is
prevented ; and an ordinary anvil, so mounted, may be used
in a dwelling house without annoying the inhabitants. To
amateurs, whose workshops are almost always- located in



THE WORKSHOP

dwelling houses, this device affords a cheap and simple relief
from a very great annoyance.

Painting Bright Metals.

When paint is applied to bright metals like tin or zinc, it
is very apt to peel off. This difficulty is greatly lessened if
the metal be hot when the paint is applied, but in many
cases this cannot be done. In such cases the surface of the
metal should be corroded, for which purpose a solution of
sulphate of copper, acidulated with nitric acid answers well.
The metal should be washed with the solution, allowed to
stand a couple of hours, and then washed with clean water
and dried.

Painting the Hours on Metal Dials. The black coloring
matter is the soot obtained by holding a clean copper or
sheet metal plate over the flame of an oil or petroleum lamp
(a glowing tool serves the purpose very well). As soon as a
sufficient deposit is produced it is collected on a piece of


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Online LibraryJohn PhinThe workshop companion. A collection of useful and reliable recipes, rules, processes, methods, wrinkles, and practical hints for the household and the shop → online text (page 9 of 16)