Handbook on Japanning: 2nd Edition by William N. Brown
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William N. Brown >> Handbook on Japanning: 2nd Edition
MODERN JAPANNING AND ENAMELLING STOVES.
The modern japanning and enamelling stove consists of a compartment
capable of being heated to any desired temperature, say 100 deg. to 400 deg.
F., and at the same time, except as regards ventilation, capable of
being hermetically sealed so as to prevent access of dust, soot, and
dirt of all kinds to mar the beauty and lustre of the object being
enamelled or japanned. Such a stove may be heated--
1. By a direct coal, coke, wood, peat, or gas fire (which surrounds
the inner isolated chamber) (Fig. 5).
2. By heated air.
3. By steam or hot-water pipes, coils of which circulate round the
interior of the stove or under the floor.
Such ovens may be either permanent, that is, built into masonry, or
portable.
[Illustration: FIG. 5.--Greuzburg's Japanning Oven.]
1. _Stoves heated by direct fire._--These were, of course, the form in
which japanning ovens were constructed somewhat after the style of a
drying kiln. Fig. 5, Greuzburg's japanning oven heated on the outside
by hot gases from furnace. The oven is built into brickwork, and the
hot gases circulate in the flues between the brickwork and the oven,
and its erection and the arrangement of the heating flues are a
bricklayer's job. Coke containing much sulphur is objectionable as a
fuel for enamel stoves Mr. Dickson emphasizes this very forcibly. He
says: "In the days when stoves were heated by coke furnaces, and the
heat distributed by the flues, the principal trouble was the escape of
fumes of sulphur which caused dire disaster to all the enamels by
entering into their composition and preventing their ever drying, not
to speak of hardening. I have known enamels to be in the stoves with
heat to 270 deg. for two and three days, and then be soft. The sulphur
also caused the enamels to crack in a peculiar manner, much like a
crocodile skin, and work so affected could never be made
satisfactory, for here again we come back to the first principle,
that if the foundation be not good, the superstructure can never be
permanent. The enamels, being permeated with sulphur and other
products from the coke, could never be made satisfactory, and the only
way was to clean it all off. The other principal troubles are the
blowing of the work in air bubbles, which is caused mainly by the heat
being too suddenly applied to the articles, but these are very small
matters to the experienced craftsman."
[Illustration: FIG. 6.]
2. _Stoves heated by hot-water pipes._--Let us first of all consider
the principle on which these are constructed. In Perkins' apparatus
for conveying heat through buildings by the circulation of water in
small-bore hot-water pipes an endless tube or pipe is employed, the
surface of which is occasionally increased by spiral or other turnings
where the heat is to be given off or acquired: the annexed figure may
serve to illustrate this principle; it represents a strong
wrought-iron tube of about one inch diameter completely filled with
water; the spiral A passes through a furnace where it is highly
heated, and the water is consequently put into motion in the direction
of the arrows; the boiling of the water or formation of steam is
prevented by the pressure, whence the necessity of the extreme
perfection and strength of the tube. B represents a second coil which
is supposed to be in an apartment where the heat is to be given out. C
is a screw stopper by which the water may be occasionally replenished.
By this form of apparatus the water may be heated to 300 deg. or 400 deg., or
even higher, so as occasionally to singe paper. A larger tube and
lower temperature are, however, generally preferable.[1]
[Illustration: FIG. 7.--Enamelling Stove--in a Tin-plate Printing
Factory--heated by Perkins' Hot-water Pipes.]
The principle of Perkins' invention has, during the last eighty
years, i.e. since the date of the invention in 1831, been very
extensively applied not only for the heating of buildings of every
description, but it has also been utilized for numerous industrial
purposes which require an atmosphere heated up to 600 deg. F. The
principle lends itself specially to the design of apparatus for
raising and maintaining heat evenly and uniformly, and also very
economically for such purposes as enamelling, japanning, and
lacquering.
The distinctive feature of this apparatus when applied to moderate
temperatures lies in the adoption of a closed system of piping of
small bore, a certain portion of which is wound into a coil and placed
in a furnace situated in any convenient position outside the drying
chamber or hot closet. The circulation is thus hermetically sealed and
so proportioned that while a much higher temperature can be attained
than is possible with a system of pipes open to the atmosphere, yet a
certain and perfectly safe maximum cannot by any possibility be
exceeded.
The efficiency of the apparatus increases within certain limits in
proportion to the pressure employed, which fact explains the
exceedingly economical results obtained, while the fact that, owing to
the high temperature used, a small-bore pipe can be made more
effective than the larger pipes used in any open system, accounts for
the lower first cost of the Perkins' apparatus.
[Illustration: FIG. 8.--Japanning and Enamelling Oven Heated by Single
Hot-water Pipes sealed at both ends with Furnace in Rear.]
[Illustration: FIG. 9--Japanning and Enamelling Oven For Bedstead,
Ironmongery, Cash-box, and Lamp Factories.]
[Illustration: FIG. 10.--Japanning and Enamelling Stove for parts of
Sewing Machines.]
It will be seen from the various illustrations that the articles to be
treated are absolutely isolated from actual contact with the fire or
the fire gases and other impurities which must be an objection to all
methods of heating by means which are not of a purely mechanical
nature. This principle not only recommends itself as scientifically
correct and suited to the purpose in view, but is also a very simple
and practical one. It affords the means of applying the heat at the
point where it is required to do the work without unduly heating
parts where heat is unnecessary; it secures absolute uniformity,
perfect continuity, and the highest possible fuel economy.
[Illustration: FIG. 11.--Japanning and Enamelling Stove for
Iron-Bedsteads and Household Ironmongery with Truck on Rails.]
[Illustration: FIG. 12--Permanent Japanning and Enamelling Stove for
Kitchen Utensils built in Masonry.]
The nature of the work to be executed in the different classes and
various sizes of stoves vary so greatly and indefinitely that only by
careful attention to the special requirements of each case, on the
part of the designers and constructors, is it possible to obtain the
most satisfactory results.
The arrangement of fixing the pipes round the lower walls of the room
in this form of stove is somewhat cumbersome, but in a roomy stove
this slight drawback is not felt quite so much. However, it seems a
good principle to leave every inch of internal space available for the
goods to be enamelled or japanned, This principle is carried out to
the letter in the other form of stoves described and illustrated in
the sequel.
The figure shows a section through single chamber japanning and
enamelling oven heated by hot-water pipes (steel) closed at both ends
and partially filled with water which always remains sealed up
therein, and never evaporates until the pipes require to be refilled.
This stove may be heated (1) by hot-water pipes (iron), (2) by
super-heated water, (3) by steam, but only to 80 deg. C. The different
compartments may be heated to uniform or to different temperatures
with hot water; the stoke-hole is at the side and thus quite separated
from the stove proper.
The ovens must be on the ground floor, so that the super-heated steam
from the basement may be available.
The great drawback to the use of gas for heating japanning and
enamelling stoves is the great cost of coal gas.
[Illustration: FIG. 13.--Portable Gas Heated Japanning and Enamelling
Stove fitted with Shelves, Thermometer, etc.]
PIGMENTS SUITABLE FOR JAPANNING WITH NATURAL LACQUER.
_White Pigments._--Barium sulphate and bismuth oxychloride. These two
are used for the white lacquer or as a body for coloured lacquers.
When the lacquer is to be dried at a high temperature barium sulphate
is preferable, but when it is dried at an ordinary temperature bismuth
oxychloride is better. Since the lacquer is originally of a brown
colour the white lacquer is not pure white, but rather greyish or
yellowish. Many white pigments, such as zinc oxide, zinc sulphide,
calcium carbonate, barium carbonate, calcium sulphate, lead white,
etc., turn brown to black, and no white lacquer can be obtained with
them.
_Red Pigments._--Vermilion and red oxide of iron. These two are used
for the red lacquer, but vermilion should be stoved at a low
temperature.
_Blue Pigment._--Prussian blue.
_Yellow Pigments._--Cadmium sulphide, lead chromate and orpiment.
_Green Pigment._--Chromium oxide (? Guignet's green).
_Black Pigment._--Lamp black. This is one of the pigments for black
lacquer, but does not give a brilliant colour, therefore it is better
to prepare the black lacquer by adding iron powder or some compound of
iron to the lacquer.
Various mixed colours are obtained by mixing some of the
above-mentioned pigments.
Examples of application are as follows:--
(1) _Golden Yellow._--Finished lacquer, 10 parts; gamboge, 1 to 3;
solvent, 5. If utensils are lacquered with this thin lacquer and dried
for about 2 hours in an air-oven at a temperature of 120 deg. C. a
beautiful hard coating of golden colour is obtained.
(2) _Black._--Black lacquer, 10 parts; solvent 2 to 4. Utensils
lacquered with this lacquer are dried for about an hour at 130 deg. to
140 deg. C.
(3) _Red._--Vermilion, 10 parts; finished lacquer, 4; solvent, 2. This
lacquer is dried for about an hour at 130 deg. to 140 deg. C.
(4) _Khaki or Dirty Yellow._--Barium sulphate, 100 parts; chromic
oxide, 3; finished lacquer, 20 to 25; solvent, 15. This lacquer is
dried for about half an hour at 160 deg. C.
(5) _Green._--Barium sulphate, 100 parts; chromic oxide, 20 to 50;
finished lacquer, 40 to 50; solvent, 20. This is dried for about 10
minutes at 160 deg. C.
(6) _Yellow._--Barium sulphate, 100 parts; lead chromate, 40; finished
lacquer, 40; solvent, 20. This is dried for about 15 minutes at 150 deg.
C.
Almost all pigments other than the above-mentioned are blackened by
contact with lacquer or suspend its drying quality.
Several organic lakes can be used for coloured lacquers, that is to
say, Indian yellow, thioflavin, and auramine lake for a yellow
lacquer; fuchsine, rhodamine, and chloranisidin lake for a red;
diamond sky blue, and patent nileblue lake for a blue; acid green,
diamond green, brilliant milling green, vert-methyl lake, etc., for a
green; methyl violet, acid violet, and magenta lake for a violet;
phloxine lake for a pink. These lakes, however, are decomposed more or
less on heating and fail to give proper colours when dried at a high
temperature.
MODERN METHODS OF JAPANNING AND ENAMELLING WITH NATURAL JAPANESE
LACQUER.
Urushiol, the principal constituent of Japanese lacquer, does not
according to the Japanese investigator, Kisaburo Miryama, dry by
itself at ordinary temperatures, but can be dried with ease at a
temperature above 96 deg. C. In the same way, lacquer that has been
heated to a temperature above 70 deg. C. and has entirely lost its drying
quality can be easily dried at a high temperature. In this method of
japanning the higher the temperature is, the more rapidly does the
drying take place; for instance, a thin layer of urushiol, or lacquer,
hardens within 5 hours at 100 deg. C., within 30 minutes at 150 deg. C., and
within 10 minutes at 180 deg. C. Japanning at a high temperature with
natural lacquer does not require the presence of the enzymic
nitrogenous matter in the lacquer, and gives a transparent coating
which is quite hard and resistant to chemical and mechanical action;
in these respects it is distinguished from that dried at an ordinary
temperature. During the drying, oxygen is absorbed from the atmosphere
and at the same time a partial decomposition takes place.
This method of japanning has its application in lacquering metal work,
glass, porcelain, earthenware, canvas, papier-mache, etc.; because the
drying is affected in a short time, and the coating thus obtained is
much more durable than the same obtained by the ordinary method.
For practical purposes it is better to _thin the lacquer with
turpentine oil or other solvent_ in order to facilitate the lacquering
and lessen the drying time of the lacquer. Since the lacquer-coating
turns brown at a high temperature, lacquers of a light colour should
be dried at 120 deg. to 150 deg. C.; and even those of a deep colour must not
be heated above 180 deg. C. _Most pigments are blackened by lacquer;
therefore the varieties of coloured lacquers are very limited._
FOOTNOTES:
[1] A question has been raised concerning the safety of
Perkins' apparatus, not merely as relates to the danger of explosion,
but also respecting that of high temperature; and it has been asserted
that the water may be so highly heated in the tubes as to endanger the
charring and even inflammation of paper, wood, and other substances in
their contact or vicinity: such no doubt might be the case in an
apparatus expressly intended for such purposes, but in the apparatus
as constructed by Perkins, with adequate dampers and safety valves,
and used with common care, no such result can ensue. Paper bound round
an iron tube is not affected till the temperature exceeds 400 deg.; from
420 deg. to 444 deg. it becomes brown or slightly singed; sulphur does not
inflame below 540 deg..
SECTION V.
COLOURS FOR POLISHED BRASS--MISCELLANEOUS.
PAINTING ON ZINC OR ON GALVANIZED IRON.
Painting on zinc or galvanized iron is facilitated by employing a
mordant of 1 quart of chloride of copper, 1 of nitrate of copper, and
1 of sal-ammoniac, dissolved in 64 parts of water. To thin mixture add
1 part of commercial hydrochloric acid. This is brushed over the zinc,
and dries a dull-grey colour in from twelve to twenty-four hours,
paint adhering perfectly to the surface thus formed.
BRONZING COMPOSITIONS.
The following are the formulae for a variety of baths, designed to
impart to polished brass various colours. The brass objects are put
into boiling solutions composed of different salts, and the intensity
of the shade obtained is dependent upon duration of the immersion.
With a solution composed of sulphate of copper, 120 grains;
hydrochlorate of ammonia, 30 grains; and water 1 quart, greenish
shades are obtained. With the following solution, all the shades of
brown, from orange-brown to cinnamon, are obtained: chlorate of
potash, 150 grains; sulphate of copper, 150 grains; and water, 1
quart. The following solution gives the brass first a rosy tint, and
then colours it violet and blue: sulphate of copper, 435 grains;
hyposulphite of soda, 300 grains; cream of tartar, 150 grains; and
water, 1 pint. Upon adding to this solution ammoniacal sulphate of
iron, 300 grains, and hyposulphite of soda, 300 grains, there are
obtained, according to the duration of the immersion, yellowish,
orange, rosy, and then bluish shades. Upon polarizing the ebullition,
the blue tint gives way to yellow, and finally to a pretty grey.
Silver, under the same circumstances, becomes very beautifully
coloured. After a long ebullition in the following solution, we obtain
a yellow-brown shade, and then a remarkable fire-red: chlorate of
potash, 75 grains; carbonate of nickel, 30 grains; salt of nickel, 75
grains; and water, 10 oz. The following solution gives a beautiful
dark-brown colour: chlorate of potash, 75 grains; salt of nickel, 150
grains; and water, 10 oz. The following gives in the first place, a
red, which passes to blue, then to pale lilac, and finally to white:
orpiment, 75 grains; crystallized sal-sodae, 150 grains; and water, 10
oz. The following gives a yellow-brown: salt of nickel, 75 grains;
sulphate of copper, 75 grains; chlorate of potash, 75 grains; and
water, 10 oz. On mixing the following solutions, sulphur separates,
and the brass becomes covered with iridescent crystallizations: (1)
cream of tartar, 75 grains; sulphate of copper, 75 grains; and water,
10 oz. (2) Hyposulphite of soda, 225 grains; and water, 5 oz. Upon
leaving the brass objects immersed in the following mixture, contained
in corked vessels, they at length acquire a very beautiful blue
colour: hepar of sulphur, 75 grains; ammonia, 75 grains; and water, 4
oz.
A GOLDEN VARNISH FOR METAL.
Take 2 oz. of gum sandarach, 1 oz. of litharge of gold, and 4 oz. of
clarified linseed oil, which boil in a glazed earthenware vessel till
the contents appear of a transparent yellow colour. This will make a
good varnish for the final coating for enamelled and japanned goods.
CARRIAGE VARNISH.
The following is used for the wheels, springs, and carriage parts of
coaches and other vehicles: Take of pale African copal 8 lb.; fuse,
and add 2-1/2 gallons of clarified linseed oil; boil until very
stringy, then add 1/4 lb. each of dry copperas and litharge; boil, and
thin with 5-1/2 gallons of turpentine; then mix while hot with the
following varnish, and immediately strain the mixture into a covered
vessel. Gum anime, 8 lb.; clarified linseed oil, 2-1/2 gallons; 1/4
lb. each of dried sugar of lead and litharge; boil, and thin with
5-1/2 gallons of turpentine; and mix it while hot as above directed.
Of course these quantities will only do for big jobs, and as it has to
do with metal, it has been thought advisable to include the formula in
this handbook.
METAL POLISHES.
The active constituent of all metal polishes is generally chalk,
rouge, or tripoli, because these produce a polish on metallic
surfaces. The following recipes give good polishing soaps:--
(1) 20 to 25 lb. liquid soap is intimately mixed with about 80 lb. of
Swedish chalk and 1/2 lb. Pompeiian red. (2) 25 lb. liquid coco-nut
oil soap is mixed with 2 lb. tripoli, and 1 lb. each alum, tartaric
acid, and white lead. (3) 25 lb. liquid coco-nut oil soap is mixed
with 5 lb. rouge and 1 lb. ammonium carbonate. (4) 24 lb. coco-nut oil
are saponified with 12 lb. soda lye of 38 deg. to 40 deg. B., after which 3
lb. rouge, 3 lb. water, and 32 grammes ammonia are mixed in. Good
recipes for polishing pomades are as follows: (1) 5 lb. lard and
yellow vaseline is melted and mixed with 1 lb. fine rouge. (2) 2 lb.
palm oil and 2 lb. vaseline are melted together, and then 1 lb. rouge,
400 grains tripoli, and 20 grains oxalic acid are stirred in. (3) 4
lb. fatty petroleum and 1 lb. lard are heated and mixed with 1 lb. of
rouge. The polishing pomades are generally perfumed with essence of
myrbane. Polishing powders are prepared as follows: (1) 4 lb.
magnesium carbonate, 4 lb. chalk, and 7 lb. rouge are intimately
mixed. (2) 4 lb. magnesium carbonate are mixed with 150 grains fine
rouge. An excellent and harmless polishing water is prepared by
shaking together 250 grains floated chalk, 1 lb. alcohol, and 20
grains ammonia. Gilded articles are most readily cleansed with a
solution of 5 grains borax in 100 parts water, by means of a sponge or
soft brush. The articles are then washed in pure water, and dried with
a soft linen rag. Silverware is cleansed by rubbing with a solution of
sodium hyposulphite.
BLACK PAINTS.
Carbon, in one form or another, is the base of all black pigments. By
far the most common of these, as used in structural plants, is
graphite. Other black pigments are lamp-black (including carbon black)
and bone-black, the former being produced in many grades, varying in
price from twopence to half a crown per pound. Bone-black, which is
refuse from the sugar-house black, varies in the percentage of carbon
contained, which is usually about 10 or 12 per cent, the remainder
being the mineral matter originally present in the bone, and
containing 3 or 4 per cent of carbonate, whilst most of the remainder
is phosphate of lime. Lamp-black is an absolutely impalpable powder,
which having a small amount of greasy matter in it, greatly retards
the drying of the oil with which it may be mixed. For this reason it
is not used by itself, but is added in small quantity to other paints,
which it affects by changing their colour, and probably their
durability. For example, it is a common practice to add it to red
lead, in order to tone down its brilliant colour, and also to correct
the tendency it has to turn white, due to the conversion of the red
oxide of lead into the carbonate.
BLACK STAIN FOR IRON.
For colouring iron and steel a dead black of superior appearance and
permanency, the following is a good formula: 1 part bismuth chloride,
2 parts mercury bi-chloride, 1 part copper chloride, 6 parts
hydrochloric acid, 5 parts alcohol, and 50 parts lamp-black, these
being all well mixed. To use this preparation successfully--the
article to be blacked or bronzed being first made clean and free from
grease--it is applied with a swab or brush, or, better still, the
object may be dipped into it; the liquid is allowed to dry on the
metal, and the latter is then placed in boiling water, the temperature
being maintained for half an hour. If, after this, the colour is not
so dark as is desired, the operation has simply to be repeated, and
the result will be found satisfactory. After obtaining the desired
degree of colour, the latter is fixed, as well as much improved
generally, by placing for a few minutes in a bath of boiling oil, or
by coating the surface with oil, and heating the object till the oil
is completely driven off The intense black obtained by this method is
admirable.
Another black coating for ironwork, which is really a lacquer, is
obtained by melting ozokerite, which becomes a brown resinous mass,
with a melting-point at 140 deg. F. The melted mass is then further heated
to 212 deg. F., the boiling-point of water. The objects to be lacquered
are scoured clean by rubbing with dry sand, and are dipped in the
melted mass. They are then allowed to drip, and the ozokerite is
ignited by the objects being held over a fire. After the ozokerite has
burned away, the flame is extinguished, and the iron acquires a firmly
adhering black coating, which resists atmospheric influences, as well
as acids and alkalies. If the black iron vessels are to contain
alkaline liquids, the above operation is repeated.
A good cheap stock black paint or varnish for ironwork is prepared, as
follows: Clear (solid) wood tar, 10 lb.; lamp black or mineral black,
1-1/4 lb.; oil of turpentine, 5-1/2 quarts. The tar is first heated in
a large iron pot to boiling-point, or nearly so, and the heat is
continued for about 4 hours. The pot is then removed from the fire out
of doors, and while still warm, and not hot, the turpentine, mixed
with the black, is stirred in. If the varnish is too thick to dry
quickly, add more turpentine. Benzine can be used instead of
turpentine, but the results are not so good. Asphaltum is preferable
to the cheap tar.
To make another good black varnish for ironwork, take 8 lb. of
asphaltum and fuse it in an iron kettle, then add 2 gallons of boiled
linseed oil, 1 lb. of litharge, 1/2 lb. of sulphate of zinc (add these
slowly, or the mixture will boil over), and boil them for about 3
hours. Then, add 1-1/2 lb. of dark gum amber, and boil for 2 hours
longer, or until the mass will become quite thick when cool. After
this it should be thinned with turpentine to the proper consistency.
VARNISHES FOR IRONWORK.
A reliable authority gives the following as a very good recipe for
ironwork varnish. Take 2 lb. of tar oil, 1/2 lb. of pounded resin, and
1/2 lb. of asphaltum, and dissolve together, and then mix while hot in
an iron kettle, taking all care to prevent the flames getting into
contact with the mixture. When cold the varnish is ready for
application to outdoor ironwork. Another recipe is to take 3 lb. of
powdered resin, place it in a tin or iron vessel, and add thereto
2-1/2 pints of spirits of turpentine, which well shake, and then let
it stand for a day or two, giving it an occasional shake. Then add to
it 5 quarts of boiled oil, shake it thoroughly well all together,
afterwards letting it stand in a warm room till it gets clear. The
clear portion can then be drawn off and used, or reduced with spirits
of turpentine till of the requisite consistency. For making a varnish
suitable for iron patterns, take sufficient oil of turpentine for the
purpose of the job in hand, and drop into it, drop by drop, some
strong commercial oil of vitriol, when the acid will cause a dark
syrupy precipitate in the oil of turpentine, and continue to add the
drops of vitriol till the precipitate ceases to act, after which pour
off the liquid and wash the syrupy mass with water, when it will be
ready for use. When the iron pattern is to be varnished, it must be
heated to a gentle degree, the syrupy product applied, and then the
article allowed to dry.