Dinah Snipes Steveni on sun 26 sep 10
This has been fun doing a bit of research. My reference for these two bodie=
s is Workshop Receipts: For Manufacturers, Mechanics, & Scientific Amateurs=
, London, by Ernest Spon, pub 1875. I'd like to think I'm a scientific amat=
eur. "Jasper Body: 10 parts chalk; 10, blue clay; 5, bones; 2, flint; 1 1/4=
blue calx. All the materials should be ground together as much depends on =
the different articles being well united, which adds greatly to the finenes=
s in colour and lustre. It fires at the temperature of earthenware ovens."
Black Egyptian Body: "235 parts blue clay; 225 calcined ochre; 45, manganes=
e; 15 Cornish clay; the materials must be accurately examined on account of=
the manganese, which ought to be free from lime or other calcareous earth;=
the pieces of ware when manufactured are very apt to crack, because of the=
sudden transition from heat to cold, provided above a certain proportion o=
f lime is contained in the manganese. This kind of earthenware requires onl=
y once burning, after which it is scoured with fine sand, and then a small =
quantity of oil rubbed over it."
Blue Calx two versions: 1. 30 parts refined regulous of zaffre; 1, plaster;=
1/2, borax. 2. 30 parts, refined regulous of cobalt; 1, plaster; 1/2, bor=
ax. If anyone is really interested I'll happily complete the recipe but it =
involves hours of heatwork, further milling, etc. I'd really like to know w=
hat the materials sub for zaffre would be? The Blue calx will not be a dee=
p and colorful stain in the body; but merely affords a bluish tint so as to=
seem whiter in appearance. Common practice. Some of the materials seem obv=
ious but I think some research/testing into blue clay would be warranted. P=
erhaps it's Blue Ball Clay? I used to use it in the UK. Anyone for firewor=
ks, or bleaching ivory, ink, gun-powder, house-paint, silvering mirrors? Oc=
hre is, of course, a reference to iron oxides and I can give chapter and ve=
rse if needed,from reference. Test. Test. Test.
Dinah
Steve Slatin on tue 28 sep 10
Zaffer is almost certainly from 'zaffera' -- the
dark blue cobalt color called (in English) Florentine=3D20
blue. Regulus of zaffer would be some kind of cobalt=3D20
oxide, I'd suspect.
=3D20
Steve Slatin --=3D20
N48.0886450
W123.1420482
--- On Sun, 9/26/10, Dinah Snipes Steveni wrote:
> This has been fun doing a bit of
> research. My reference for these two bodies is Workshop
> Receipts: For Manufacturers, Mechanics, & Scientific
> Amateurs, London, by Ernest Spon, pub 1875. I'd like to
> think I'm a scientific amateur. "Jasper Body: 10 parts
> chalk; 10, blue clay; 5, bones; 2, flint; 1 1/4 blue calx.
> All the materials should be ground together as much depends
> on the different articles being well united, which adds
> greatly to the fineness in colour and lustre. It fires at
> the temperature of earthenware ovens."
>=3D20
> Black Egyptian Body: "235 parts blue clay; 225 calcined
> ochre; 45, manganese; 15 Cornish clay; the materials must be
> accurately examined on account of the manganese, which ought
> to be free from lime or other calcareous earth; the pieces
> of ware when manufactured are very apt to crack, because of
> the sudden transition from heat to cold, provided above a
> certain proportion of lime is contained in the manganese.
> This kind of earthenware requires only once burning, after
> which it is scoured with fine sand, and then a small
> quantity of oil rubbed over it."
>=3D20
> Blue Calx two versions: 1. 30 parts refined regulous of
> zaffre; 1, plaster; 1/2, borax.=3DA0 2. 30 parts, refined
> regulous of cobalt; 1, plaster; 1/2, borax. If anyone is
> really interested I'll happily complete the recipe but it
> involves hours of heatwork, further milling, etc. I'd really
> like to know what the materials sub for zaffre would
> be?=3DA0 The Blue calx will not be a deep and colorful
> stain in the body; but merely affords a bluish tint so as to
> seem whiter in appearance. Common practice. Some of the
> materials seem obvious but I think some research/testing
> into blue clay would be warranted. Perhaps it's Blue Ball
> Clay? I used to use it in the UK.=3DA0 Anyone for
> fireworks, or bleaching ivory, ink, gun-powder, house-paint,
> silvering mirrors? Ochre is, of course, a reference to iron
> oxides and I can give chapter and verse if needed,from
> reference. Test. Test. Test.
>=3D20
> Dinah
> =3D0A=3D0A=3D0A
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