AN IMPROVED METHOD OF COVERING IRON AND STEEL WITH LEAD AND ITS
Year: 1883

page_text: LETTERS PATENT to William Heather Spence of 8 Quality Court, Chancery
Lane in the County of Middlesex Patent Agent for an Invention of "AN
IMPROVED METHOD OF COVERING IRON AND STEEL WITH LEAD AND ITS
"
ALLOYS communicated to him from abroad by Emil Möhlau of Düsseldorf in
the Empire of Germany Manufacturer
PROVISIONAL SPECIFICATION left by the said William Heather Spence at
the Office of the Commissioners of Patents on the 6th April 1883.
WILLIAM HEATHER SPENCE of 8 Quality Court, Chancery Lane in the County
of Middlesex Patent Agent "AN IMPROVED METHOD OF COVERING IRON AND
STEEL WITH LEAD OR ITS ALLOYS (a communication to me from abroad by Emil
Möhlau of Düsseldorf, in the Empire of Germany, Manufacturer)
">
In the known methods of covering iron with lead where molten lead is poured
on clean or tinned surfaces of iron, blisters (through the formation of gas) and
cracks or crevices (through the unequal contraction of the metals on cooling) are of
frequent occurrence.
Although these may be to a certain extent filled up by subsequent hammering or
rolling, it is impossible to avoid the danger of small holes or crevices reappearing
when the apparatus so covered with lead is in use. It is also impossible to avoid
damage to such lead coverings when plates so covered are bent or otherwise
manipulated.
In order to avoid these difficulties it is necessary to cover with lead apparatus
or parts of machinery in their complete form and this is done in the following
manner. The apparatus when ready to be covered with lead or alloy, is made
perfectly clean by treatment with dilute sulphuric acid then soldering liquid is
applied (consisting of a solution of zinc in hydrochloric acid) then it is tinned and

page_text: finally the lead (or alloy) covering is fused on to the tinned surface piece by piece
by means of the flame of a suitably arranged oxyhydrogen blowpipe.'
In this way no gas can be confined under the surface of the lead (or alloy);
this method as above stated can be readily applied to the covering of irregular
surfaces as the lead or alloy can be fused on by a very little at a time and is
therefore very much more under the control of the manipulator than if the molten
metal were poured upon the iron or steel in the ordinary way.
Also the being enabled in this manner to apply a great heat locally as before
described makes each fresh piece of lead (or alloy) covering as it is fused on, unite
homogeneously to the preceding one, thus forming an unbroken surface when
complete.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Heather Spence in the Great Seal Patent Offico on the
6th October 1883.
.
WILLIAM HEATHER SPENCE of 8 Quality Court Chancery Lane in the County
of Middlesex Patent Agent "AN IMPROVED METHOD OF COVERING IRON AND
STEEL WITH LEAD OR ITS ALLOYS "
a Communication to me from Abroad by
Emil Möhlau of Düsseldorf in the Empire of Germany Manufacturer
In the known methods of covering iron with lead where molten lead is poured
on clean or tinned surfaces of iron blisters (through the formation of gas) and
cracks or crevices (through the unequal contraction of the metals on cooling) are
of frequent occurrence.
Although these may be to a certain extent filled up by subsequent hammering
or rolling it is impossible to avoid the danger of small holes or crevices reappearing
when the apparatus so covered with lead is in use.-It is also impossible to avoid
damage to such lead coverings when plates 80 covered are bent or otherwise
manipulated In order to avoid these difficulties it is necessary to cover with lead
apparatus or parts of machinery in their complete form and this is done in the
following manner.
The apparatus which must be constructed of wrought iron or of iron having a
surface which does not contain more carbon than ordinary wrought iron when
ready to be covered with lead or an alloy of lead is made thoroughly clean by
treatment with dilute sulphuric or other suitable acid.-The clean surface is then
treated with ordinary soldering fluid (consisting of a solution of zinc in hydro-
chloric acid) and covered with a film of tin in the usual way.-Finally the lead or
alloy of lead is fused on to the tinned surface piece by piece (2.e. small quantities
of metal are continually added to the metal already deposited in such a manner
that they fuse together and become homogeneous) by means of the flame of a
suitably arranged oxyhydrogen blowpipe. It is not necessary for this purpose
that the oxygen used in the blowpipe should be undiluted. The ordinary oxy-
hydrogen flame which is produced by the mixture of hydrogen and air answers
perfectly well.
Great care on the part of the workman is necessary in all the details I have
described in order to obtain satisfactory results.-If the process has been carefully
carried out in this way no gas can be confined under the surface of the lead (or
alloy). This method as above stated can be readily applied to the covering
of irregular surfaces as the lead (or alloy) can be fused on by a very little at a
time and is therefore very much more under the control of the manipulator
than if the molten metal were poured upon the iron or steel in the ordinary way.
Also the being enabled in this manner to apply a great heat locally as before
described makes each fresh piece of lead (or alloy) covering as it is fused on unite
homogeneously to the preceding one thus forming an unbroken surface when
complete
It is necessary that the heat of the flame should be sufficient not only to fuse
the small quantity of lead but also to raise the temperature of the iron to such a
point that the fusion of the fresh addition of metal with that previously deposited
and their adherence to the tinned surface may be complete.-In some cases it may
be advantageous to apply extraneous heat as well as the blow pipe to the apparatus
to be coated in order to produce the desired result.
Having thus described the nature of the said Invention and in what manner the

page_text: same is to be performed (communicated to me from abroad as aforesaid) I hereby
declare that what I claim as of the said Invention is:
The application of the oxyhydrogen flame to the covering of iron with lead or
alloys thereof substantially as described.
In witness whereof I the said William Heather Spence have hereunto set my
hand and seal the sixth day of October in the year of our Lord One thousand
eight hundred and eighty three.
Witness
FRANK REDMAN
8 Quality Court
Chancery Lane
W. H. SPENCE, (L.S.)