The Olneyville times. (Olneyville [Providence, R.I.]) 1887-1917, 1901-08-23
COUNTERFEIT GOLD.
GLIDING POWDERS ARE MADE or
COPPER AND SPELTER.
How the Material That Gives the
Shining, Metallic Finish tn Mirror
and Picture Frames IL Produced.
Gold Leaf without Gold.


Gold Leaf without Gold.
How many Sersons who see the shin
Ing gold In colored printing and on
mirror and picture frames know that
gold does not enter at all into the com
position Of the stuff that produces these
golden effectsi
The shining metallic effect II pro-
duccd by n fine powder made from a
mixture Of bronze and spelter. This
offers the cheapest and best means Of
giving the rich surface demanded In
wall papers, printing. lltbography, fres-
Going and In vast range Of manufac-
turcd articles Of wood, paper and iron.
The material used Is so called Dutch
metal, an alloy OF copper and spelter.
The relative proportions nre varied TO
produce different colors. The larger
the percentage OF spelter the lighter or
more yellowish will be the tint Of the
alloy.
The copper and spelter are smelted In
graphite crucibles containing about 400
pounds OF metal, which, when com
pletely fused, IL run off into molds,
forming half round ingOts two feet
long by half an inch In thickness. Aft
or cooling these are bound Into bundles
md sent 10 the rolling mill. where they
are passed cold nine times through n
double set OF steel rolls under cnor-
nous pressure. This nattens them and
draws them out into thin ribbons from
30 10 90 feet long and something more
than one inch wide. Cold rolling un-
der such extreme pressure makes the
metal brittle, so II passes 10 the an
neallng furnace, which Is heated by
wood fire, ns the sulphur In coal or
coke would be Injurious TO the ribbons.
Having been softened and rendered
ductlle by anneallng, they are cleansed
I'm an acid bath, cut into lengths OF
about three feet and collected I'm bun
dies OF 40 or 30 strips each. They are
laid between sheets Of zinc and passed
under hammers which beat the metal
strips 10 the thlnness OF tissue paper.
This requires six successive beatlngs.
and great skill must be exercised to
produce n uniform and unbroken foil.
After the third beating the metal strips
arc taken from between the sheets OF
zinc, loosened from each other and
clcnnscd by immersion I'm bath OF
tnrtrate OF potassium. The cleaning II
repeated after the last beating, and the
sheets are hung on lines to dry. In the
beginning the rolled strips are n dull
gray metallic color, at the fourth beat
Ing the yellowlsh 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
squares, which are laid together by
hand I'm packets OF several hundred
each and incloscd within an envelope
OF sheet brass. The packets return to
the anneallng furnace, where they are
softencd by heating and slow cooling.
and then go TO the beaters, where they
nre reduced under flattenlng hammers
TO the thlnness OF real gold leaf. so thin
that Il can be blown away by the
breath.
The manufacture OF bronze powder
consists I'm grading clipping and pull
yerlzng the various bronze foils TO an
even, impalpable powder and Is nm In
dustry OF comparatively recent date.
1t began as n means OF using up and
utilizing the imperfect leaves which
came ms waste from the bcaters OF
gold. silver and bronze. These were
cut by hand into fine clippings and
then ground TO powder I'm hand mills OF
simple construction. With the lapse or
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.
The beating process fiattens out n
pound of copper and spelter alloy to nm
area of about 800 square feet, and in
this condition the square sheets as they
como from the brass envelopes are
shcarcd into small fragments and rub
bed with olive oil through n steel sieve
having ten meshcs to the inch and then
passed TO the stamping and grinding
machines, where they are pulverized by
steam or water power TO the bronze
powder OF commerce. The grinding
occupies from one TO four hours. ac-
cordIng TO the grade or quality OF the
powder to be produced, which Is of
four grades. from coarse to supertine.
The supernuous oil Is removed by heat
ing under pressure, and the powder
is then carried into centrifugal clari-
ficrs, or Gradlng machines, which. turn
Ing M high speed. expcl the powder
through fine orlhccs In the form OF
dust. which settles on lnclosed shelves,
according to weight and hneness the
finer particles at the top, the coarser
below, and In this way the powder Is
divided into It's various grades.-New