Gilding. 
Gilding 
cap. 
Colouring 
the gild- 
ing by 
heat, 
er gilder’s 
wax, 
or saline 
preparation, 
278 
gild, and places ‘it «upon the fire; and he takes them 
one'by one with the tongs, out of this pan, to brush 
them, and then returns them to heat, whilst he brushes 
others: at last, to finish the operation, he holds them 
in the tongs over the hottest part of the charcoal; 
this completes the evaporation of the mercury, and 
leaves the gold of a dull yellow, or gold colour, Small 
articles of which there are a great number of the same 
size, such as buttons, rings of watch chains, &c. are 
put all together into an iron frying pan to heat, and 
when the mercury begins to flow, they are all together 
thrown out into a-cap, in which they are shaken up, 
and well stirred about with a painter’s brush. This ope- 
ration effects the spreading of the gold with very little 
trouble. It should be repeated several times, and the 
heat brought on very gradually, which the pan admits 
of doing more conveniently than any other means. As 
the heat continues to increase, the mercury begins to 
evaporate, and soon leaves the amalgam, or rather the 
gold, fixed upon the surface. The work. being now 
dried off, presents only a ‘dull scarfy appearance; but 
being*brushed by a few strokes of the scratch-brush, it 
assumes a polished surface. The brushing is done 
with small beer or ale grounds, which however contri- 
bute nothing more-to the operation than to soften the 
strokes of the brush, and prevent the work having any 
appearance of seratches. If a thicker coat of gilding 
is required, the operation is repeated once or twice, 
and every time the colour will approach nearer to that 
of fine gold. The scratch-brush must be applied to 
clean the work between each gilding. 
The simplest mode of heightening the colour, is to 
hold the work over the charcoal of a small stove, simi- 
lar to the gilders stove, and heat it till the colour in- 
creases, During the heating, if any spots appear of a 
different colour, they are touched with a stick dipped 
in aquafortis, which restores them. It is then thrown 
into a weak solution of aquafortis and water, which 
will discover any spots where the coating of gold is de- 
ficient. This method is supposed to act by making a 
perfect dissipation of the mercury ; but we think it ra- 
ther operates to produce a farther alloy or amalgama- 
tion of the gold with the metal upon which it is spread. 
The work being again polished with the scratch-brush, 
is finished unless a very high polish is required: it must 
be produced by burnishing with a blood-stone, using 
water to prevent the gold being rubbed off. 
When a higher colour is required, the work iis co- 
vered with a composition called gilding wax; and be- 
ing held over the fire till the wax smokes, and is onthe 
point of inflaming, it is then suddenly cooled in water, 
and the scarf of the wax is cleared off by the scratch- 
brush and beer. 
Gilding wax is compounded of bees wax and red 
chalk in equal quantities, with French verdigris and 
alum or green vitriol, which are added in small ‘por- 
tions. The use of the wax seems to be only to flow, and 
carry the other ingredients to every part of the sur- 
face, and to determine the proper degree of heat to be 
applied, There is another preparation of sal ammo- 
niac, nitre, green vitriol, and verdigris, in equal parts, 
which they use after the wax is cleared off, and they 
desire to produce a very high colour. It is spread over 
the work in a state of paste, to which it is mixed by 
urine, and heated till it smokes in the same manner 
as the wax. This composition may be used instead of 
the gilding wax; or, by repeating the application of 
the gilding wax two or three times, it will uce the 
same colour, which is a deep and brilliant copper | 
GILDING. 
colour, but very superficial, and wears off long before 
the gilding is worn away. faatitie 2 ot (yaa 
Dead yellow is a preparation of gilding which pre- 
sents a frosted surface, without any polish, and of a“ 
beautiful yellow colour. It is produced by a saline 
preparation like that above, but some yellow. colouring 
matter is employed instead of the green verdegris, 
When the work is heated with this upon it, it is thrown 
into aquafortis and water, and the ebullition which this 
occasions produces the dead colour. che 
The operation of drying off, as formerly practised, 
was very prejudicial to the health of the workman, _ 
who always inhaled the fumes of the mercury. . The /™P 
application of a glass front to the chimney inwhich 
the stove is placed, has obviated this inconvenience ; 
but still the stove is not judiciously constructed with a 
view of producing a gradually mereasing heat. A_ 
considerable improvement might be made by employ- 
ing an iron box, or oven, set in brick-work, over a close 
fire, and surrounded. by flues, in the same manner as 
a boiler. It should be open in front, and have two or 
three shelves within it. The whole stove should be 
inclosed within a chimney, with a glass window in front, 
and a sufficient draft up the chimney window to carry 
off all the fumes. In using this stove, the work should 
at first be laid on the top of the box, where it will be 
gradually warmed; then the workman removing it to 
the upper shelf, it would become more heated, and fit 
for brushing. When this is done, he should place it 
on the second shelf, which would produce a greater 
heat. Being again brushed, and afterwards placed on 
the bottom of the box or stove, the heat would be suf- 
ficient to complete the drying off. ‘ ’ 
Iron or steel, may be ornamented by eee Gildin 
if the surface is first covered with copper, by dipping itn 
the iron into a strong solution of blue vitriol, alphas 
of copper.) Upon this the amalgam can be applied ; but 
such gilding presents a very indifferent colour, and is 
not durable. : post. 4 } 
Another method is, to spread a thin plate of gold By bu 
upon the steel, then heating them both, and burnish- 8 
ing the gold down, it will adhere, but so slightly as to 
have but little durability ; and the heat must be so con- 
siderable, that it frequently injures the temper of the 
steel. 
In the Philosophical Magazine, vol. ii. anew mode of 
gilding steel is described, as being the same by which By eth 
the Sohlinger sabres cr xd oe solution of a4 go 
Id in nitro-muriatic acid, (aqua regia,) being poured 
fae about twice as much ether, the latter will pa 
the surface of the acid; but if shaken vepethes, the gold 
will be taken up from the acid by the ; which may 
then be separated, by pouring the mixture into along — 
glass funnel with the tube stopped, and when it is com- As 
pletely at rest, the tube being o ; 
acid; and being again | 
with gold in solution, 
to be 
which, 
nishing the gilding down. Gh ti 
t 
ed, by , size, white of an egg, or drying oil. ort 
giktine cant applied on as well ae wood ; or; kind 
with an priate cement, it may be laid on any sub- 
stance which presents a surface sufficiently even, and 
