DOI Page / Citation link:
https://doi.org/10.11588/diglit.19571#0153
THE ARTIST'S ASSISTANT. 139
oils of fpike or lavender, except that it wants the
glutinous quality which makes them ferviceable in
fpreading the enamel. But with refpeci to the ufe
of the oils of olive and linfeed. or any other fub-
ftantial oil, it is very detrimental : tending to re-
duce the metalline calxes ; and leaving a fmall pro-
portion of black coal or afhes, which muft neceffa-
rily injure the white colour of the ground.
When plates, as in the cafe of pictures, dial-
plates, &c. are to be enamelled, they fhould always
be made convex on the outfide, and concave within ;
and all pieces of enamel, formed of metal, where the
figure does not admit of their being thick and folid,
fhould be of the fame kind or form. Otherwife
they will be very apt to warp in the heat, and can-
not be brought ftraight, after they are taken out of
the fire, without cracking the enamel. For this
reafon, likewife, it is proper to enamel the work all
over, as well on the wrong as right fides, to pre-
vent the heat from calcining the metal ; which
would both contribute to its warping, and weaken
the texture of it.
The enamel being laid on the body to be enamel-
led, when the fixt muffle is ufed, the piece muft be
gently lifted on to the falfe bottom ; and put in
that ftate into the muffle fixt in a furnace, by thruft-
img the falfe bottom into it as far as it will go. But
it is belt to defer this till the fire be perfectly in or-
der, which may be known by putting a bit of tile
or china with iome enamel on it of the fame tone
with that ufed as a proof ; and another proof of the
fame kind may be alio put along with the work into
the muffle ; which, being taken out, may fhew how
the operation proceeds.
S a Pit-coal
oils of fpike or lavender, except that it wants the
glutinous quality which makes them ferviceable in
fpreading the enamel. But with refpeci to the ufe
of the oils of olive and linfeed. or any other fub-
ftantial oil, it is very detrimental : tending to re-
duce the metalline calxes ; and leaving a fmall pro-
portion of black coal or afhes, which muft neceffa-
rily injure the white colour of the ground.
When plates, as in the cafe of pictures, dial-
plates, &c. are to be enamelled, they fhould always
be made convex on the outfide, and concave within ;
and all pieces of enamel, formed of metal, where the
figure does not admit of their being thick and folid,
fhould be of the fame kind or form. Otherwife
they will be very apt to warp in the heat, and can-
not be brought ftraight, after they are taken out of
the fire, without cracking the enamel. For this
reafon, likewife, it is proper to enamel the work all
over, as well on the wrong as right fides, to pre-
vent the heat from calcining the metal ; which
would both contribute to its warping, and weaken
the texture of it.
The enamel being laid on the body to be enamel-
led, when the fixt muffle is ufed, the piece muft be
gently lifted on to the falfe bottom ; and put in
that ftate into the muffle fixt in a furnace, by thruft-
img the falfe bottom into it as far as it will go. But
it is belt to defer this till the fire be perfectly in or-
der, which may be known by putting a bit of tile
or china with iome enamel on it of the fame tone
with that ufed as a proof ; and another proof of the
fame kind may be alio put along with the work into
the muffle ; which, being taken out, may fhew how
the operation proceeds.
S a Pit-coal