improvements in or relating to Cathodes Employed in Galvanoplastic or Electrotyping Processes.
Year: 1897

page_text: improvements in or relating to Cathodes Employed in Galvanoplastic
or Electrotyping Processes.
I, ABEL JULIEN, of 8 Avenue de la Republique, Paris, in the Republic of France;
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
The cathodes used for galvanoplastic or electrotyping processes are generally
covered with plumbago in order to prevent the formation of copper or other
metallic deposits upon them.
In order to make the plumbago more adherent it has been hitherto generally
mixed with oil or fat; but this has numerous advantages, the principal of which
are the following:-
1st. The slightest friction on the plumbago thus prepared and applied to the
cathode by spreading it or in any other manner, causes the plumbago to fall off
and the metallic deposit to adhere to the cathode, or in the case of plane or semi-
spherical surfaces no deposit is formed at all if only fat remains on the cathode.
2nd. In case of cathodes having spherical or perfectly round surfaces, the plum-
bago applied as has been described, does not allow the deposits formed to be
removed without tearing them off, especially if they are thick, and then it
becomes necessary to remelt them and to repair the damaged cathode, whatever be
its form.
3rd. If the deposit is of slight thickness a number of small holes will be found
in the deposited surface.
4th. Finally, plumbago mixed with oil or fat gives a soft and very easily
removed or damaged surface, as has been mentioned.
To obviate these drawbacks I made experiments with substances which could
be mixed with plumbago, instead of oil or fat, and the substances which gave
the best results were the following:-
Essence of turpentine, benzine, mineral essences petroleum alcohol and xylol.
Of these substances I preferably use essence of turpentine by means of which I
obtain perfect deposits.
I find that the proportion of from 100 to 250 grammes of plumbago to one
kilogramme of the essence of turpentine gives very suitable results, the quantity
of plumbago being varied within the above limits according to the thickness
which it is desired to give to the plumbago coating.
This mixture is sufficient for the deposits to be effected on plane or semi-
spherical surfaces, but when round or spherical surfaces are used, I prefer to add
to this mixture for each kilogramme of the essence of turpentine and according
to the degree of hardness and adhesion required, up to 50 grammes of resin which
I'dissolve and then mix with the plumbago as in the preceding example.
Resin is not the only substance which enables me to increase the hardness and
the adhesion of the plumbago coating, but I prefer it, although colophony, gum-

page_text: arabic, yellow wax, paraffin, and Canada balsam also give good results, and I
may also use them in some cases.
Having thus obtained the necessary plumbago-compound I apply it to the
cathodes whatever be their form and whatever he the objects to be treated, and
when they are suitably coated with this new compound, I rub them, at first slowly
and then quickly till the liquid of the compound evaporates and it becomes dry.
In this manner I obtain cathodes having smooth, brilliant and dry surfaces and
the plumbago-coating is perfectly secured.
Improvements in or relating to Cathodes Employed in Galvanoplastic
or Electrotyping Processes.
I, ABEL JULIEN, of 8 Avenue de la Republique, Paris, in the Republic of France,
Civil Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
The cathodes used for galvanoplastic or electrotyping processes are generally
covered with plumbago in order to prevent the formation of copper or other
metallic deposits upon them.
In order to make the plumbago more adherent it has been hitherto generally
mixed with oil or fat; but this has numerous disadvantages the principal of
which are the following.
1st. The slightest friction on the plumbago thus prepared and applied to the
cathode by spreading or in any other manner, causes the plumbago to fall off
and the metallic deposit to adhere to the cathode or in the case of plane or semi-
spherical surfaces no deposit is formed at all if only fat remains on the cathode.
2nd. In case of cathodes having spherical or perfectly round surfaces, the plum-
bago applied as has been described, does not allow the deposits formed to be
removed without tearing them off especially if they are thick, and then it
becomes necessary to remelt them and to repair the damaged cathode, whatever be
its form.
3rd. If the deposit is of slight thickness a number of small holes will be found
in the deposited surface.
4th. Finally, plumbago mixed with oil or fat gives a soft and very easily
removed or damaged surface as has been mentioned.
To obviate these drawbacks I made experiments with substances which might
be mixed with plumbago, instead of oil or fat and the substances which gave
the best results were the following:-
Essence of turpentine, benzine, petroleum essence, petroleum alcohol and xylol
or the like. Of these substances I preferably use essence of turpentine by means
of which I obtain perfect deposits.
I find that the proportion of from 100 to 250 grammies of plumbago to one
kilogramme of essence of turpentine gives very suitable results the quantity
of plumbago being varied within the above limits according to the thickness
which it is desired to give to the plumbago coating.
This mixture is sufficient for deposits to be effected on plane or semi-
spherical surfaces, but when round or spherical surfaces are used, I prefer to add
to this mixture for each kilogramme of the essence of turpentine and according

page_text: to the degree of hardness and adhesion required, up to 50 grammes of resin which
I dissolve and then mix with the plumbago as in the preceding example.
Resin is not the only substance which enables me to increase the hardness and
the adhesion of the plumbago coating but I prefer it, although colophony, gum-
arabic, yellow wax paraffine and Canada balsam also give good results and I may
also use them in some cases.
Having thus obtained the necessary plumbago-compound I apply it to the
cathodes whatever_be_their_form_and whatever_be_the_objects_to. be treated_and
when they are suitably coated with this new compound I rub them at first slowly
and then quickly till the liquid of the compound evaporates and it becomes dry.
In this manner I obtain cathodes having smooth, brilliant and dry surfaces and
the plumbago coating is perfectly secured.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. A composition for coating cathodes used in galvanoplastic or electrotyping
processes consisting of a mixture of plumbago with a volatile liquid such as
essence of turpentine, benzine, petroleum essence, petroleum alcohol xylol or the
like substantially as described.
2. A compound such as described in Claim 1 having in addition a substance
such as resin colophony, gum arabic yellow wax paraffine Canada balsam or the
like substantially as and for the purpose described.
Dated this 1st day of Santember 1807
BOULT & WADE,
Agents for the Applicant.