Clinch Valley news. [volume] (Jeffersonville, Va.) 18??-2019, 1895-08-09
GLASS PAPER.
That Would Be a Moro Accurate De.
signation than sandpaper.

etguation than nndpapcr.
sandpaper as now made is false to
Its name, for 1t has no sand about It,
the place OF that material being now
taken usually by powdered glnss, which
: does its,work with vastly greater effect.
One OF the most important operations
IN the fabrication OF sandpaper is the
,pulyerization OF the glass into powder
of the different grades of fineness. Com
monty an iron mortar is used for this
purpose, q heavy iron pestle being the
crushing instrument. Stamping ma
chinery is better. Itconsists OF stout
box, whose iron side walls serve as n
3 base for the stamping machinery. In
the box, which can be closed by wood
en- door to prevent waste OF material
and also injury to the workman, are
two iron cylinders in which play the
stamps. These crush the glass, turning
on their own axles as they work.
For grading the powder several shift
@ing cylinders nre necessary, covered
with gauze of different mesh. Begin
ming with the coarsest the workman
/, proceeds gradually to the finest re-
sitting each time that which passes
through the network.
The paper to be used In the manu-
facture must be good, strong and rather
long-fbred; 1t must also be free from
/ knots and Irregularities, and IL there
be any such they must be planed of.
II they should be overlooked, they
! would interfere with the proper use Of
the sandpaper; the knots would pro-
trude through the glue, and little ridges
and channels would result, making 1t
impossible to smooth of a surface
! evenly with the paper.
The paper is cut into large sheets,
spread on work tables, fastened down,
and then painted. by means of large
I brush, with thin, even coat of hot
glue. If the glue is too thin and tho
paper of bad quality, the glue soaks
into the paper, so that which re-
mains is not Of sufficient consistency to
hold the glass. Thus results n sand.
paper from which the glass easily rubs
off, or which, in places, has no glass
| ut all, or not enough. This is notably
the case with the coarser varieties, In
which the layer of glue must he put on
with exceeding. care that the relatively
large fragments of glass, which can in
no manner be soaked with the binding
material, may be held fast in it. On
the other hand, If the layer Of glue is
too thick or the consistence too viscous,
the outer part hardens too quickly, SO
that the glass powder cannot embed
\ Itself in It,
When the glue has been spread on
the paper the powdered glass must be
sifSed ON through an appropriate sieve.
y This operation also requires considera-
bic skill, through not so much as the
spreading of the glue. For the glass
I must not be sifted merely in such a
manner rs to use II given quantity to
! sheet. but so that each sheet may be
covered evenly. Even then all the
( powder will not stick, and some of the
particles lie upon others without touch
Ing the glue; these can be shaken of
by n slight movement of the paper.
When the super1uous glass powder
has been removed n wooden roller Is
passed lightly over the paper to press
the particles of glass as firmly as DOS.
sible into the glue and to form a per.
fectly even surface.