IMPROVEMENTS IN THE MANUFACTURE OF PORCELAIN FIRE CLAY BATHS
Year: 1883

page_text: LETTERS PATENT to John Hall of Stourbridge in the County of Worcester
Manufacturer of Enamelled Baths and Bricks for an Invention of "IMPROVE-
PROVISIONAL SPECIFICATION left by the said John Hall at the Office of
the Commissioners of Patents on the 29th January 1883.
JOHN HALL of Stourbridge in the County of Worcester Manufacturer of
Enamelled Baths and Bricks "IMPROVEMENTS IN THE MANUFACTURE OF PORCELAIN
FIRE CLAY BATHS
"
My invention has for its object improvements in the manufacture of Porcelain
Fire clay Baths by which means I am enabled to produce a bath which is not only
enamelled inside but with a beautiful enamel or glaze outside also which has been
a desideratum in the trade for a long time. To meet this need many attempts
have been made to enamel the outside in the same way as that used for the inside.
Up to the present time all the effects have failed though many modifications of the
inside process have been tried. Probably this has been caused from the exceeding
hardness of the enamel used for the inside coupled with the contraction inwards
leaving the outside coating separated from the body of the bath and in consequence
cracked and falling off in patches.
Now my invention consists in the additional outside process i.e after the bath is
in all other respects completed according to the old process of making such baths
I take an enamel paint which may be compounded as follows:―
Priming powder thinned with Dockers priming mixture applied thickly on the
bath. The bath is then placed in a stove of 220° Fahrenheit for eight hours.
When cold rub down smooth with lump pumice stone. When this is done a second
coat is applied just as before explained. Then apply a coat of White lead, Red,
Green, Blue Grey, Vermillion, Black, Chocolate ochre or other colour mixed with
Dockers Transparent Amalgamating Varnish The bath is now stoved for ten
hours in a beat of 170 degrees and when cold is rubbed down as before mentioned.

page_text: This process is repeated twice more. Next apply a coat of Dockers special
polishing enamel and again stove in a heat of 170 degrees for fourteen hours or in
the case of superior finished baths apply after it is dry a second coat of the
enamel. Then rub down with powdered rotten stone and polish up by hand
known as
"Hand up." The temperature may be varied to some extent according
to the time the bath is exposed to heat.
It will be obvious that baths so made require no outside wood casing, and they
are thus cheaper, and therefore occupy less space when fixed, and they are also
much cleaner as the outside may be perfectly cleansed as well as the inside, they
are therefore well adapted for the use of Hospitals, Infectious wards, Workhouses,
Schools and other similar purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Hall in the Great Seal Patent Office on the 26th July
1883.
JOHN HALL of Stourbridge in the County of Worcester, Manufacturer of
Enamelled Baths and Bricks "IMPROVEMENTS IN THE MANUFACTURE OF PORCELAIN
FIRE CLAY BATHS"
My invention has for its object improvements in the manufacture of Porcelain
Fire clay Baths by which means I am enabled to produce a bath which is not only
enamelled with porcelain inside but with a beautiful enamel or glaze outside also
which has been a desideratum in the trade for a long time. To meet this need
many attempts have been made to enamel the outside in the same way as that
used for the inside. Up to the present time all the efforts have failed though
many modifications of the inside process have been tried. Probably this has been
caused from the exceeding hardness of the enamel used for the inside coupled
with the contraction inwards leaving the outside coating separated from the body of
the bath and in consequence cracked and falling off in patches.
Now my invention consists in the additional outside process i.e after the bath is
in all other respects completed according to the old process of making such baths
I take an enamel paint which may be compounded as follows:-
Priming powder thinned with priming mixture applied thickly on the bath.
The bath is then placed in a stove of 220 degrees Fahrenheit for eight hours.
When cold rub down smooth with lump pumice stone. When this done a second
coat is applied just as before explained. Then apply a coat of White lead, Red,
Green, Blue, Grey, Vermillion, Black, Chocolate ochre or other color mixed with
Transparent Amalgamating Varnish. The bath is now stoved for ten hours in a
heat of 170 degrees and when cold is rubbed down as before mentioned. This
process is repeated twice more. Next apply a coat of polishing enamel and again
stove in a heat of 170 degrees for fourteen hours or in the case of superior finished
baths apply after it is dry a second coat of the enamel. Then rub down with
powdered rotton stone and polished up by hand known as "hand up." The
temperature may be varied to some extent according to the time the bath is
exposed to heat.
It will be obvious that baths so made require no outside wood casing, and
occupy less space when fixed and they are also much cleaner as the outside may be
perfectly cleansed as well as the inside, they are therefore well adapted for use in
Public Baths Asylums, Hospitals, Infectious wards, Workhouses, Barracks, Schools
and other similar purposes.
Having now described my said Invention of improvements in the manufacture
of Porcelain Fire clay Baths and the manner of carrying the same into practical
effect I would have it understood that I do not confine myself to the exact number
of degrees of heat used or great minuteness in the details as some margin is left for
variations without materially altering the general effect of the invention but what
I do claim is :-
Making Porcelain Fire clay Baths with an outside enamel or glaze substantially
as herein set forth.
In witness whereof I the said John Hall have hereunto set my hand and seal
this nineteenth day of July in the year of Our Lord One thousand eight
hundred and eighty three