US1423569A - Wall board and plaster composition adapted thereto - Google Patents

Description

J. A. LOCKHART.

WALL BOARD AND PLASTER COMPOSITIONUADAPTED THERETO.

APPLICATION FILED APR. 3, 192|.

Patented July 259 1922.,

JAMES A. @MAART LWEWTQR JAMES A. LOCKHART, 0F BUFFALO,A NEWvYORK, ASSIGNOR TO PITHO PLASTIC BOARD COMPANY, INC., OF BUFFALO, NEW YORK, A CORPORATION OF NEW YORK.

Masses.

Specification of Letters Patent.

Patented July 25, 1922.

applicati@ mea April a, 1921. serial 1ra-459,737.

vide wall board which shall be very light in weight, which shall be without brittleness and which will not crack consequent to nailing, which shall be 'waterproof and fireproof, whose body shall be sufficiently porous to produce good suction effects and whose surface shall be sufficiently rough to produce good keying effects in connection with the application of outside finishing material, such as Keene or Portland .cement or stucco,

and which shall be exceedingly cheap to manufacture.

In the accompanying drawing;

Figure l is an elevation of the wall board in accordance with the invention, showing more particularly the rough surface thereof to which the finishing material is applied.

Figure 2 is a sectional View of the same, and

Figure 3 isa view showing the shredded wood fibres which constitute an essential ingredient of the wall board.

The ingredients of the composition are plaster of Paris, lime (stone or refined) and. shredded wood fibres.

While the proportions of the composition are not absolute I have found that the best results are obtained by providing about three parts, by weight, o-f plaster of Paris for one part of lime, and by providing the shredded wood libres in a quantity slightly less, by weight, than the plaster of Paris.

The shredded wood fibres lare not tobe confounded with excelsior saw dust, paper pulp or any merely generically required fibrous filler. These shredded wood fibres have a definite and characteristic form and a definite proportional relation to the fin?.

parted to the finished wall board.

B the term shredded wood fibres as use herewith and in the claims I refer to wood fibres of .peculiar formation, that is to say fibres which are from three-quarters of an inch toone and oneuarter of an inch in length, more or le, an are quite coarse, somewhat irregular in their form and for the most part of what might be called compound formation, that is to say several of the fibres running in the same general direction willbe somewhat loosely united as a cluster. As far as practical the fibres are illustrated in Fig'. 3. They are, of course, light and flexible, although having sufficient coarseness and stiffness.

The inigbredients'are thoroughly mixed together, a r which the composition is compressed and formed into wall board in any suitable or known manner, one surface of the board, however, being left rough or unfinished, as shown in Figures l and .2, and the other surface being ypreferably smooth. The rough surface cooperates with outside finishing material such as cement or stucco and the smooth surface cooperates with inside finishing material such as paint, calcimine or wall paper.

For most industrial purposes Vthe finished Wall board should be about a quarter of an inch thick, the shredded wood fibres being several times greater in length than the thickness of the board. These fibres not only extend throughout the entire mass, functioning most effeotually as a reinforcement, but also will be exposed along the surface of the board and will produce the desired and requisite roughness of the surface to which the finishing material is to be applied. As exposed along such roughened surface the shredded wood fibres will exfend in all directions in the general plane of such' surface and will also extend at various angles to such plane. Thus the roughened surface is characterized by closely associated ridges, projections and indentations of irregular form, proportion and extent by virtue of which good keying effects are produced. c The fibres, by virtue of their body, i. e., ooarseness and clusteringf relative sti- `ness and irregularity of outline, while serv- This preserves a certain porosity throughout the mass which is not incompatible with good waterproof qualities but which has the advantages, first of enabling the board to dry very quickly in course of manufacture, and second, of providing for eilicient suction effects When the finishing material, Keene or Portland cement or stucco is applied. These suction effects in connection with the keying effects of the roughened Surfaceinsure a mos-t secure application of the finishing material.

The shredded Wood fibres in addition to the advantages specified also eliminate any quality of brittleness or riability, and iusure that the Wall board will not crack under nailing.

In addition to the material specified a small quantity of sand may be added to give body but While this is preferred it is not at all necessary. c Y

Having fully Claim:

1. Plaster composition for Wall board comprising plaster of Paris, lime and shredded Wood fibres.

-2. Plaster composition for Wall board described my invention, I'

comprising plaster of Paris, lime and shred` fibres being several times being several times greater in length than the thickness of the board.

5. Wall board composed of a mixture of plaster of Paris and lime and shredded Wood fibres incorporated therein, the fibres being several times greater in length than the thickness of the board and producing a roughened surface to which finishing m'aterial may be applied.

In testimony whereof I aiix my signature.

JAMESA. LOCKHART.

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