US1218394A - Coating for molds and cores. - Google Patents

Description

.rived from hard washed coke of a UNITED SATES JOSEPH EMILE GERNELLE-DANLOY, OF MOU'LIN S,

PATENT OFFIC.

FRANCE.

COATING FOR MOLDS AND 'CORES.

No Drawing.

France, have invented certain new and useful Improvements in Coatings for Molds and Cores, of which the following is a specification.

The present invention relates to a product destined to replace black lead and other products usually employed to coat molds and cores made out of sand, which are intended to be dried or baked before casting.

This product can be employed for castings of steel, cast-iron, copper, bronze, aluminum and all metals'in general. My improved product is composed of coke dust, wood charcoal, pipe clay, and starch, the latter partly in the form of powdered raw starch and partly in the form of a dried starch paste. 3

Under the term cokedust I desire to be understood quality suitable for'metallurgical operations and ground to a fine powder. The ingredients named form a com osition which when mixed with water to cm a paste capable of being applied to the mold or core by means of a brush, produces a-' thin but hard and smooth coating which does not detract from the quality and appearance of the cast metal, prevents the ad herence thereto of sand from the mold or core. so that the castings 410 not need any subsequent cleaning, and enables castings to be obtained which are free from surface cracks and blemishes.

The resistant and coke dust and fire clay are already known in connection with coatings for molds and cores and flour has also been employed .therewith in compositions for the same urpose. These compositions have hitherto een v used without any specialagglutinative additions, or in someinstances sour beer has been proposed as an agglutinative. however found that the addition I have of dried Specification of Letters Patent.

the impalpable powder 'debroken out of the sand is protective qualities of Patented Mar. 6, 1917.

Application filed December 10, 1914. Serial No. 876,479.

which is in eflect dextrin and flour paste,

water (whereas flour. itself is is soluble in not fully soluble and only very slightly agglutinative) provides a perfect agglutinative and produces in combination with the other ingredients mentioned a composition the employment of which gives greatly improved results. The foregomg materials are em ployedin the new product in the following. f

proportions Coke, washed 40 Charcoal .1 32.5% Pipe-clay 22.5% Starch paste, dry 2 Starch, raw, inpowder 3 These quantities. may vary slightly ac cording to the quality of the materials employed. These are pulverized together and very finely bolted, giving an impalpable and.

very homogeneous powder of a blackish shade.

This product is employed mixed with an equal volume of water, and is applied tothe surface by means of a brush and when dried appears like an enamel varnish. The taking I made without necessitating other work than the ordinary removal of the mold, obviating the rasping of the pieces after the casting. The castings obtained have a very smooth surface and the metals keep their qualitiesfand their natural shade; the castingsare very-clean and do not soil when they are touched as do those obtained with the use of black lead or all other similar materials, which has a certain importance when the pieces, have to be finished.

Moreover, the weight of the newproduct is 40% less. than that of an equal quantity of black lead of good quality, which permits of a great economy from its use.

Having thus described my invention and the manner to work it out, I claim patent for: r v

1. A composition for use in coating sand molds and cores, comprising in combination coke dust, charcoal, pipe clay and raw 2. A compos't1on for use in coating sand molds and cores comprising known carbonaceous mixtures previously employed for this purpose together with an agglutinant consisting of dry starch paste.

In witness whereof I have signed this specification in the presence of two wit- 10 nesses.

mum EMILE GERNELtE-MNLW.

Witnesses: I

JEAN 4 GnRMAm, Louis GomoHoN.