US439658A - Carl hettwig - Google Patents

Description

UNITED STATES PATENT OFFICE.

CARL HETTVVIG, OF BERLIN AND FRITZ HEOKNER, OF BRAUNSOHXVEIG, GERMANY.

PROCESS OF PRODUCING ORNAMENTAL DESIGNS UPON WOOD.

SPECIFICATION forming part of Letters Patent No. 439,658, dated November 4, 1890. Application filed February 21, 1890. fierial No. 841,361. (No specimens.)

To all whom it may concern.-

Be it known that we, CARL HETTWIG and FRITZ HECKNER, subjects of the Emperor of the German Empire, residing, respectively, at Berlin and Braunschweig, in the German Empire, have invented certain new and useful Improvements in Process for Producing Orna mental Designs upon Wood, of which the following is a specification.

This our invention relates to a new process for tinging the natural surface of wood or producing thereon picturesque designs of different shades from a light-brown to a dark-brown color that will not fade from exposure to light or to the changes of the weather. This process consists in the discovery of certain chemicals to be applied in successive order upon the natural surface of the wood and then the sotreated surface to be eXposetLto the chemical action of the daylight.

It is a well-known process 'to coat the surface of metal, stone, or of a material of organic origin and of a homogene nature with a layer of varnish and then to tinge the open spots or etchings with an acidiferous or coloring liquid for bringing forth a design upon the thus treated surfaces. For producing, however, an ornamental design upon the natural surface of wood has had its difliculties, caused by the organic cellular construction of wood. The varnishes for etchings are generally of a diaphanous and frequently of a coloring nature, and therefore must be removed after having served their purpose. For wood this is not practical, because every mechanical operation of removal is liable to injure the surface of the wood, While adissolving liquid in washing off the varnish is apt to soak into the wood andrender its surface with an unclean appearance. It has been found necessary, therefore, to provide a varnish for coating the wooden surface around the spots to be tinged or colored that is colorless and transparent and will not require removal, but contrary to remain as an advantageous protector and which will not produce a luster or burnish like the usual varnishes do. The varnish we have discovered to have the aboved'esired properties consists of a strong solution of caoutchouc in chloroform; and for the purpose of preventing the solutions applied for bringing forth the design from spreading beyond the outlines of the design by running out into the fibers of the wood we previously soak the surfaces with a solution of alum in the same manner as is usual for wood to be painted upon. After the surfaces of the wood have been thus treated with alum and the outlines of the design have been drawn or marked thereon in any usual manner, the quickly-drying caoutchouc varnishis applied in proper conformity with the design upon all parts of the wooden surface not to be colored. Now the unvarnished surfaces of the wood are to be soaked with a solution of bi chromate of copper, (cuprum bichromicum,) and after this solution has been well absorbed, but before it has become dry, a solution of pyrogallic acid is applied. The so-treated Wooden surface, still insignificantly showing the design, is now exposed to the daylight, which slowly will bring forth a durable and chemically almost indestructible union between the bichromate of copper and the pyrogallic acid by chemical transformation under cooperation of the fibers of the wood, and within about twenty four hours will be brought forth upon the tinged surfaces a more or less dark-brown color.

The two ti'nging solutions can be made and applied in different proportions-that is, from one part of salt or acid in one hundred parts of distilled water up to the most concentrated solutions. With a stronger solution of bichromate of copper and thereupon a weaker solution of pyrogallic acid we obtain greenishplaying color shades; and otherwise, again,a weaker solution of bichromate of copper combined with a stronger solution of pyrogallic acid will produce a reddish brown. Weak solutions in general will produce a lighter coloring and stronger solutions darker colors, and thus in proportion as solutions of different strength are applied for different portions the design can be shaded, and thereby wonderful effects can be produced. After the action of the daylight thereon the work is completed.

What we claim is 1. The process of tinging the natural surin chloroform,next for bringing forth the design in color the applying of a sol utjon of bichroniai'e of copper, and upon this again a solution of pyrogxallic acid,and finally exposing the so-t-reated surfaces to the daylight, all substantially as set forth.

In testimony whereof We affix our signatures in presence of two Witnesses.

CARL llE'lTWIG. FRITZ IIECKNER. Witnesses:

FREDK. V. CROSBY, ULRICH R. MAERZ.