US 2760921 A
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Description (OCR text may contain errors)
M. POLLACK TEST PENCIL Aug. 28, 1956 Filed Jan. 18, 1954 INVENTOR MflfT/A/ P01 LACK ATTORNEY United States Patent TEST PENCIL Martin Pollack, Brooklyn, N. Y.
Application January 18, 1954, Serial No. 404,750
2 Claims. (Cl. 2041) This invention relates to a tester for plating baths and more particularly to a pencil adapted to test the plating properties of plating baths.
Plating baths used for plating for example gold from cyanide solutions or chromium from a composition bath containing chromium ion, must have an optimum solution strength to obtain most effective and tenacious deposits of the plated metal on to a base stock metal.
According to this invention a pencil made from a suitable alloy or metal is employed, said pencil being given a freshly cleaned and brightened surface before being immersed in the plating bath.
This invention is described by means of a plurality of illustrative embodiments shown in the accompanying drawing in which:
Fig. l is a side view of a pencil having a conical point,
Fig. 2 is a section view taken on line 22 of both Fig. 1 and Fig. 3,
Fig. 3 is a side view of a modified pencil having a flat ovaloid point, and
Fig. 4 is a front view of the modification of Fig. 3.
Referring to the drawing a solid cylinder of soft metal capable of accepting a displacement deposit upon immersion in the plating bath is provided with a conical point 11 by being inserted in a conventional pencil sharpener used for sharpening graphite pencils. The soft metal employed may be zinc, zine alloys, aluminum, aluminum alloys and the like having the critical property of accepting a deposit or particular type of deposit of the plated metal under test.
The metal may be, for example, Zamac a trade-marked alloy of zinc and aluminum having the composition, zinc 80 to 90%, aluminum 1 to 20%, and copper 0.1 to 5.0%, or it may be a hard metal, for example, a steel alloy. Where the metal is hard and therefore can not be sharpened by a common pencil sharpener, I use emery cloth, sand paper or other means for producing a flat freshly cleaned surface 12. The pencil may be of cylindrical, square, or other rectangular or curvatured cross-section,
especially so when not sharpened by a pencil sharpener. It is preferably provided with a pencil clip 13 secured to the body portion 10 by means of conventional rivets or screws 14 so that the pencil may be clipped to a coat pocket when not in use.
In using the pencil, the point 11 or flat surface 12 as the case may be, is freshly cleaned to expose the bright metal surface free from oxide or tarnish deposits. This brightly prepared surface is then dipped or immersed into the bath being tested and a displacement deposit is or is not produced depending upon the strength of the solution, the pencil being selected of such a metal or metal alloy as to produce a plated deposit when the bath strength and other properties are correctly adjusted to effect commercial plating results. The pencil may be provided with a rubber top (not shown) to enhance its appearance as a pencil.
Example A high speed copper plating bath having 4 to 12 ounces of copper cyanide per gallon and 2 to 10 ounces of sodium cyanide per gallon was tested by a pencil prepared from zinc die cast metal given a freshly brightened surface by a pencil sharpener. A deposit of copper on the bright surface indicated the strength to be not correct for plating purposes.
All Water soluble metal complex-cyanide solutions used for plating purposes may be tested by this invention. Generally speaking, no deposit signifies too little free cyanide ions in the bath. Correct deposit may be indicated by a coloration deposit, for example, a brass colored deposit when using high speed copper plating solution and a zinc-aluminum alloy pencil.
This invention has been illustrated and described by means of a plurality of embodiments but other embodiments are obviously intended to be covered by the claims herein.
1. A process for testing a complex cyanide electroplating bath which comprises immersing a newly brightened pencil consisting essentially of zinc into said bath and then observing the color due to the extent of copper deposition.
2. The process according to claim 1 wherein the composition of the pencil is to percent zinc, 1 to 10 percent aluminum and 0.1 to 5.0 percent copper.
References Cited in the file of this patent UNITED STATES PATENTS 511,468 Sillich Dec. 26, 1893 1,501,745 Carroll July 15, 1924 2,492,214 Fonda Dec. 27, 1949