The Middlebury register. [volume] (Middlebury, Vt.) 1850-1882, 1878-02-01
Electro-Plating.

coming more and more into fashion ev-
cry year. The present age il one of
utilitarian tendencies, and IL being
found that certain articles, covered
with gold or silver, look as well, and,
II not subject to rough usage, last n
number of years, aud are, to ali intents
and purposes, as good as if made of the
pure metals, electlO-plating is becom-
ing more and more popular every year.
10 be sure, when the usefulness of plat
ed articles is past, they are not so yalu-
able as II made of gold or silver; but
when 1t is computed that while in use
the interest on their cost was not n
third as much as il made of the pure
metals, 1t will be seen that, after all.
economy recommends their use in pre
ference. Besides, If the style of the
articles is not out of fashion, or il makes
little difference as to style, they can be
replated al small cost, and made To
renew their term of service. Heavily
plated table ware, mountings of har-
nesses, watch cases, and even jewclrv
OF some Kinds, can be rcplatcd with sill
yer or gold, as the case may be, and
continue in the service. There are
three methods of covering base metals
with gold. One is by the battery pro-
cess, which 1t is here proposed to de-
scribe. The second is by placing gold
on each side of copper or brass fiiling
and rolling them out into a largo sheet
the articles to be made from this being
struck out with dies, etc., etc. This
kind of plating can only be made be-
fore the article is formed. IL Is much
more durable than an electro-deposit,
because the latter must be of pure gold,
which is quite soft, while the gold used
IN rolled plate can be made quite hard
bY being alloyed with copper, etc. The
third method is what is known as fire
gliding. This is the old method, but is
now nearly obsolete, both in this coun-
try and in Europe, electro. plating alto
gether taking its place. Some years
ago, however, before the electro pro-
cess was in vogue, all plating was done
in IN this way. The father Of Mr.. Vim
cent Laforme, of this city, was the first
who started the business of gliding in
Boston. He came to Boston from Ger
many, in 1882, and for many years was
the only one of his trade in it. His son.
Vincent Laforme, served thorough
apprenticeship to this branch of the bu-
siness, and is, perhaps, the only one in
Boston who thoroughly understands it.
In gliding by fire, as in electro-gilding,
the first requisite is to have the article
to be covered with gold thoroughly
clean and free from grease spots and
discolorations. The gold to be used Ia
cut up fine, and, together with about
ten times its weight of quicksilver. is
put into heated crucible, where 1t
soon becomes amalganated, aud ia of the
consistency of putty. A box is then
filled with lighted charcoal, and the ar
ticle, after being dipped in q solution
OF mercury in nitric acid, il covered
with the amalgam and placed upon the
burning Goals which are famed to keen
the fire alive. As the heat acts upon
the metal the mercury is evaporated.
leaving the gold closely adhering to it.
In order, however, that the precious
metal shall be evenly distributed, dur-
ing the process of evaporation of the
mercury it is kept constantly spread by
means of brush fitted for the purpose.
When the mercury is all evaporated the
article is found covered with gold,
which, however, may not be of a color
to suit the glider. lie then uses paste
composed of saltpetrc, sulphate of zinc
and common salt, or other Ingredients
which be burns upon the gold plating
and obtains thereby beautiful high
color, or the particular color desired
"But," said Mr.. Laforme, "thouph we
could put Oh thicker coating of gold
by hre gliding, il is no better than cleo
tro-plating,, and Is very unhealthy
work, owing to the evaporation of the
mercury, which is inhaled by the work.
men. have been so saturated with
mercury, from this cause, that |
conld not hold piece of metal in nv
hand for a minute without its being
coated with that metal" The same
process was also used in depositing sill
YER by the fire process; but, as stated
before. it has gone out of use altogetll-
or. Electro-gilding, which has taken
its place, is done by making the metals
into a wcssolution and depositing by
battery power. The best clectro-natcrs
prepare their solutions by what is
known as the battery process. To pre-
pare a solution of gold a given quantity
of cyanide of potassium Is dissolved in
water and the solution heated to about
l5O Fahr.; then deep cup, called n
porous cell, is filed with the cyanide
solution and placed inside the other So
luton; into this cell Is put q small
plate of platinum or other metal. attach
ed by wire to the zinc pole of the bat
terry. A piece of gold is placed in the
large solution, facing the plate In the
porous cell, and attached to the other
pole of the battery by wire. The ac-
ton of the battery dissolves the gold.
which is held in solution by the liouid.
and when the desired amount is pnt in
solution the porous cell is removed and
the solution is ready to do its work.
The articles to be gilt are thoroughly
cleansed, attached TO the negative pole
of the battery, and placed in the solu-
ton. the positive pole being attached to
q mixture of carbon and some other
metal called an electrode. The deposit
IL generally made In a few minutes.
The hotter the solution the less battery
power is required. Generally battery
of three or four cells is used, and the
solution is kept at 130 to i50 Fahr. But
one cell will answer if the solution Is
heated TO 200 deg. According 10 the
amount deposited, so will be its dura-
bility. A few grains will serve TO give
a gold color to very large surface. but
il will not last. This proves, however.
that the process may be used for The
most inferior quality of gliding. Gold
thinly laid upon silver will bo Of a light
color, because of the property of The
gold TO transmit light. Tho solution
for gliding silver is made very hot, but
for copper 1t is of minimum heat. A
mere blush of gold may be sufficient for
articles not subjected to wear: but on
watch cases, pencil cases, chains, and
the like, good coating should be Civ
en-. An ordinary sized watch case
should have from twenty grains TO one
pennyweight; a mere colorlng will he
sufficient for the inside, but the outside
should have as much as possible. A
watch case, thus gilt, for ordinary
wear, will last for FIVE or six years
without becoming bare. Solutions of
silver for silyer-plating are also made
by the haifary nrneass In a xrau eonao