US533420A - Building-plaster - Google Patents

Description

. 25 the surface.

PATENT FF- BUILDlNG-PLASTER.

SPECIFICATION forming part of Letters Patent No. 533,420, dated February 5, 18195. Application filed November 9, 1894. Serial No. 528,338. (No specimens.)

diana, have invented anew and useful Build- 1ng-P1aster,of which the following is a specification.

This invention contemplates the productlon of a building plaster wherein the surface,

when dry, will be harder and smoother than heretofore, and wherein the surface will be free from lath stains.

Ordinarily the surface of building or wall plaster is rough and brittle, and it is neces- I 5 sary to its finished state that a surface coating or finish be applied, whereby to endow it with a hard and smooth surface. Again, the

moisture attending the wet plaster is invariably transmitted to the laths, which causes the wood of which they are composed to give out or expel a colored substance. This permeates the plaster and shows on the face thereof, making what are known as lath stains, and greatly impairing the beauty of Now, by means of my invention these disadvantages are overcome; and the invention lies in the compounding and use of an ingredient for the plaster which I term, for the purposes of trade, the chemical, which is 0 formed of such ingredients as are capable of performing the functions which the objects of my invention require. Thus the lath stainr ing is prevented by the application of sulphate of zinc and alum to the laths, which 3 5 acts on them chemically and prevents the giving off of the colored fluid or stain referred to above.

The plaster is made to harden and to have a smooth glossy surface by combining with its constituent ingredients flour, sugar, lime,

and oil-cake meal, which elements enter into the composition and, by means of a chemical affinity not necessary to be here set forth, causes them to dry slowly, and this operation,

5 together with certain latent influences which the said elements exert, causes the surface of the plaster to have that appearance and those attributes which it is one of the objects of my invention to attain.

The plaster for which my chemical is best adapted is composed of the following ingredients: sand, (sharply formed grains,) eight hundred pounds; plaster of paris, four hundred pounds; fire clay, (pulverized,) thirty pounds; hair, one pound; chemical, twelve pounds. These ingredients should be G0ll1 bined with the requisite amount of water and mixed into a thoroughly homogeneous mass, as is usual in such cases and as will be understood. It will also be understood that the mixing may be performed by any suitable means, mechanical or manual. In the aforegoing formula the words sharply-formed grains, preceding sand, mean sand which is composed of grains having sharp points and edged sides, this being the kind of sand usually employed for building purposes. It may also be explained that fire clay means clay which is similar to that used for fire brick and ground to the requisite degree of fineness.

p The chemical is composed of the following named elements or ingredients: alum,

(pulverized) fifty pounds; flour, (wheat) one hundred and fifty pounds; sugar, (granulated) one hundred pounds; lime, (ground) six hundred pounds; oil cake meal, two hundred pounds; sulphate of zinc, twenty-five pounds. This also should be thoroughly mixed and made as nearly homogeneous as possible. There should not, however, be any liquid applied, since the chemical is kept dry until combined with the plaster compound. In this latter compound the several ingredients, being endowed with a chemical affinity, combine to produce a new substance, which, owing to its new attributes, effects the several ends before explained. Thus the flour, sugar, lime and oil-cake meal operate as a retarder, to make the operation of setting slow, gradual and regular, and at the same time, or consequently, act to give the finished plaster a hard and smooth surface. Similarly, the alum and sulphate of zinc enter into association with the wood of the lathe and by their influence prevent the throwing off of the stain aforesaid, by counteracting the chemical operation which is set up by the combination of the Wet plaster and wood, and. causing the stain to be, not formed.

Having described the invention, I olain1- In testimony that I claim the foregoing as my own I have hereto affixed my signature in the presence of two Witnesses.

As an ingredient of building plaster, alum, WILLIAM H. AIKMAN. 5 wheat flour, sugar, lime, oil-cake meal, and Witnesses:

sulphate of zinc, combined substantially as LOUIS A. MEYER, and in the proportions stated. JAMES KING.