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THE MUSIC TRADE REVIEW
VARNISHES AND THE VARNISHER.
The Causes of Cracking, Checking and Shrinkage in the Finish of Piano Cases—Difficulties
of the Work and the Remedy Offered—A New Invention and Its Great Possibilities.
By H. A. Norton, of Boston.—{Third
Article.)
[Editor's Note—The series of articles running in these
•columns herewith are of great value and interest, having
Jbeen prepared by an expert on the varnish question. They
should be read by piano manufacturers, dealers and
others who experience constant trouble in the matter
•of the varnished surface of piano cases—certainly one of
the greatest annoyances to the manufacturer.—Editor
The Music Trade Review.]
hard as cement if given time to thoroughly dry
out, i. e., for the oil and japan to absorb oxygen.
Silica, to use its common name, is undoubtedly
the best and safest base for paste fillers.
Some manufacturers, however, use starch.
The claims for its virtue rest on its becoming a
No one will claim that the contraction and ex- more homogeneous mass than a powdered min-
pansion of the different substances is identical in eral, and thus holding out the varnish better.
•degree, and the more substances there are, the Starch easily undergoes chemical decomposition,
more trouble there is sure to be. As before thus changing its nature as well as its physical
properties. Dilute acids convert it into dextrin,
stated, the shrinkage on filled wood consists of
3. depression over the filler in the pore of the and the prolonged action of acids convert the
wood, thus showing conclusively that the shrink- dextrin into glucose. It is quite possible that
age of any varnish is unequal as it settles into the linoleic acid which is present in all drying
the filler, and stands up on the actual wood it- oils has this action on a starch filler. Starch is
self. Where the surface is exactly alike, as in not the best base for fillers, although in expert
the case of a piece of glass, shrinkage of two or hands does excellent work. It has the tendency
more coats of varnish might, and does take of not anchoring itself to the wood, and in hot
place, but as it is equal over the entire surface, weather is much inclined to "punch out," i. e.,
be squeezed out of the pores, throwing up little
it does not show.
The piano manufacturer who is using no paste ridges of the varnish. If the latter be brittle, it
cracks; if elastic, it bends up over the filler, and
filler, no shellac, and is filling the tiny cells of
the wood with varnish, giving ample time for the as in the case of the new, skin coat varnish, the
surface can be blocked down with rotten stone,
first two coats to shrink, and who gives plenty of
time for all the coats to harden before rubbing, is and present a surface as good as new, though the
laying the foundation for a reputation for fine surface cannot be permanent, because the filler is
apt to come and go in the pores, and the elastic
varnish work, and an enduring finish.
varnish
comes and goes with it.
Since, however, paste fillers are in such gen-
The following seems a perfectly reasonable
eral use, i t is of interest to examine into their
ingredients, and try and determine which has argument: Take a piano case on which the ve-
the best qualifications for the purpose. Paste neers are unquestionably seasoned, the staining
fillers are made from a drying oil, japan, turpen- thoroughly dry, and a silica filler given plenty of
tine, and a base either vegetable or mineral. time to harden; have the varnishing done in
The consensus of opinion favors floated silex, or a most approved manner, so that all the varnish
silica, which is finely divided quartz. In chemis- is thoroughly seasoned, and beyond question will
try, it is Silicic Oxide. It is chemically inert not shrink any more. Expose the case to a long-
period of dampness, as at the seashore for the
as far as its uses go in paste filler.
It becomes a vitreous mass of the same chemi- summer, or a long stretch of very hot, humid
cal nature as before it was heated. There is only weather, and even the above case, on which
one acid which will affect it. the same acid used months were spent in finishing, shows shrinkage,
in etching on glass—hydrofluoric acid. When as all piano men know.
mixed in proper proportions with good oil and a
The reason is this: the wood swells in spite
high-grade japan, the resultant filler becomes as of the finish over it, but the silica filler is not
ESTABLISHED 1892.
PIANO LEGS AND PILASTERS
PANELS AND CARVINGS
MAURER BROTHERS.
HITTLE-P01KTEI
swollen, as a temperature of even 115 degrees F.
has no effect on silica, which will not melt in an
ordinary furnace, and undergoes fusion only
when introduced in the flame of the oxyhydrogen
blow-pipe. As the paste filler is mostly silica,
the minute particles being held together in a hard
mass by the oil and japan, it does not swell at
any ordinary temperature, or from moisture,
but the wood swells and pushes out the varnish
a little beyond the varnish over the filler in the
pores, and it appears as if the varnish had
shrunken in the pores, and the manufacturer is
told that his varnish shrinks. On the resumption
of cool weather and normal humidity, the wood
slowly resumes its normal volume, but the var-
nish has lost some of its brilliancy, owing to
slight unevenness between the part over the
wood and the part over the filler, which means
it does not regain its former perfectly level sur-
face.
Any manufacturer can prove this by finishing
one-half of a panel with varnish over a silica
paste filler, and on the other half, use the same
grade of varnish, but no filler, giving a long time
for the finishing operation, and then submit the
panel to a damp temperature of 100 degrees F.
for two weeks.
It is well known that if the one coat of lin-
seed oil varnish be applied over a coat that is
not dry, it takes a very long time for both coats
to harden. This is because linseea varnish forms
a skin, which prevents or retards the oxygen
penetrating further into the coat. This is not
the case with the new oil varnish, because when
the process of hardening begins, the solidification
goes on, as before stated, throughout the entire
coat, and having once started, is not so easily
checked. As a proof of this, it is recorded that a
workman varnished a rack of panels in the
morning with the skin coat varnish, and var-
nished them again in the afternoon, thinking he
had a rack which had been varnished two days
before. The mistake was discovered, and the
rack watched. It was given a few days extra
drying time, and when machine rubbed, gave no
evidence of the mistake, as the panels did not
sweat nor pit, showing that solidification of the
varnish was but slightly retarded, if at all.
When it is necessary to remove the varnish
from cases, it is a common practice to flow the
varnish with hot glue. As the glue hardens i t
shrinks very much, and being strongly attached
to a brittle varnish, cracks and peels off the var-
nish. Owing to an accident, it became necessary
to remove five coats of the skin coat varnish
mentioned from a panel, and it was given a flow
coat of hot glue.
NEW YORK.
515 West 42d Street (Rear).
IT WON'T HURT THE DEALER
Any to See that
THE MAPES
STRING
is on his Pianos.
VENEERS
3T
(To be continued.)
Jesse LaDow, agent for the B. Dreher's Sons
Co., of Cleveland, has commenced replevin pro-
ceedings in the justice court of T. B. Jarvis,
against George Spoolman. alias R. E. Regan, to
recover a Crown piano, a pianola, a bench, a
piano stool and a piano cover, on the strength o f
a chattel mortgage, says the Mansfield, O., News.
C. H. O. HOUGHTON
ESTABLISHED 1824 BY E. (Si C. W. HOVGHTON
96 FIFTH AVENUE
NEW YORK CITY
Phone, 6935 Grecmercy
BOTHNER-SCHMIDT ACTION CO.
Grand Rapids
Piano
Case
Co.,
Ltd.
GRAND RAPIDS, MICH.
1941-1945 PARK AVE., COR. 1 3 1 " ST.
NEW YORK
The most modern and
complete exclusive
case factory in the
world.
QUALITY AND PROMPT SHIPMENTS GUARANTEED
A. C. CHENEY PIANO ACTION CO.
Manufacturer^ p£ HIGH GRADE PIANOFORTE ACTIONS.
CASTLETON, NEW YORK