Evening journal., 1901-09-19
COUNTERFEIT GOLD.
GLIDING POWDERS ARE MADE o
COPPER AND SPELTER.

How the Material Tint Gives tn
Shining, Metallic Finish to Miro.
and Picture Frames Is Produced
Gold Leaf without Gold.
how many persons who see the shin
ing gold in colored printing and OF
mirror and picture frames know tina
gold does not enter at all into the com
position Of the stuff that produces tbes
golden effects?
The shining metallic effect is pro
duced by fine powder made from
mixture Of bronze and spelter Thi.
offers the cheapest and best means oil
giving the rich surface demanded IN
wall papers, printing, TYPOGRAPHY. fires
! Going and in vast range of manufac
tured articles Of wood, paper and iron.
The material used is so called Dutci
metal, an alloy of copper and spelter'
( The relative proportions are varied td
produce different colors. The larger
the percentage of spelter the lighter oil
more yellowsh will be the tint of thd
alloy.
The copper and spelter are smelted irI
| graphite crucibles containing about 400
pounds of metal, which, when com
plctely fused, is run off into moldsI
forming half round ingots two feet
] long by half an inch in thickness. Aft
or cooling these are bound into bundles
and sent TO the rolling mill, where they
| are passed cold nine times through a
! double set Of steel rolls under enor-
nous pressure. This hattens them and
| draws them out into thin ribbons from
| 90 to 60 feet long and something more
than one inch wide. Cold rolling I'M
der such extreme pressure makes the
metal brittle, so it passes to the an
i healing furnace, which is heated by.
wood fire. as the sulphur In coal or
coke would be injurious to the ribbons.
j Having been softened and rendered
| ductile by annealing, they are cleansed
i In an acid bath, cut into lengths of
4 about three feet and collected in bun
dies of 40 or 30 strips each. They are
laid between sheets of zinc and passed
4 under hammers which beat the metal
strips to the thnness Of tissue paper.
This requires six successive beatings,
and great skill must be exercised to-
D. llANIuAt d ullAOlAl anu ulAbAOhNn LNAAs
After the third beating the metal strips
?, are taken from between the sheets Of
u zinc loosened from each other and.
\ cleansed by immersion in a bath of
B. tartrate of potassium. The cleaning is.
I repeated after the last beating. and the.
Il sheets are hung on lines to dry In the
4 beginning the rolled strips are a dull
gray metallic color. at the fourth beat
8 ing the yellowish color begins to show,
and after the sixth they are clear and
bright as gold.
The defective leaves are then thrown
out and the perfect ones cut into small
I squares, which are laid together by
hand in packets of several hundred
each and inclOsed within an envelope
of sheet brass. The packets return to
the annealing furnace, where they are
softened by heating and slow cooling
and then go to the beaters, where they
are reduced under flattening hammers
TO the thinness of real gold leaf, so thin
that it can be blown away by the
breath. as-s..
( TIC lfSnufactJn'e OF bronze powder
consists N grinding, clipping and pull
verifying the various bronze foils to an
even, impalpable powder and IS an in
dustry of comparatively recent date.
1t began as a means Of using up and
utilizing the imperfect leaves which
came as waste from the beaters Of
gold, silver and bronze. These were
cut by hand into fine clippings and
then ground to powder In hand mills of
simple construction. With the lapse of
time and the spread Of artistic indus
tries the uses of bronze powder in
creased until the demand far outran
the supply Of waste, and the leaf metal
= is now made on large scale.
d The beating process flattens out a
= pound Of copper and spelter alloy to an
y area of about 500 square feet, and in
- this condition the square sheets as they
= como from the brass envelopes are
# shcared into small fragments and rub
h bed with olive oil through n steel sieve
q having ten meshos to the inch and then
passed to the stamping and grinding
machines, where they are pulyerized by
steam or water power to the bronze
J.. powder Of commerce. The grinding
occupies from one to four hours, ac
IA cording 90 the grade or quality of the
~ powder to be produced, which is OF
four grades from coarse TO superfine
I. The superAuous oil Is removed by heat
q ing under pressure, and the powder
~ IS then carried into centrifugal clari
fers, or grading machines. which, turn
~ ing at a high speed, eXpel the powder
y through fine orifces in the form Of
Il dust. which settles on inclosed shelves
according to weight and fineness, thu
&c finer particles at the top. the coarsei
below, and in this way the powder II
T. divided into its various grades.-NeN
h. York Press.
e.