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280 ILLUSTRATED WORLD
wood as seasoned and dry as possible
before laying the paint.
When it comes to painting that iron
gate, or ornamental bench on the lawn, or
that galvanized iron piping a new problem
presents itself. Here however, as
in the case of wood, it is best to remove
all of the old paint first. Ordinary paint
has an annoying tendency to scale' off
iron. If it is not practicable to remove
the old coating, the surface may be prepared
by using the mixture of various
ingredients. Dissolve in one-half gallon
of water, one ounce of chloride of copper
and the same quantity of nitrate of copper
and sal ammoniac. For mixing, an
earthen, not a metal pot or jar should be
employed. Next add one ounce of crude
hydrochloric acid. The mixture should
be applied immediately, a flat brush being
used for the purpose. If this has been
properly done the iron surface in the
course of several hours will turn black
and when thoroughly dry will be gray.
Within twelve or fifteen hours' time
brush the surface with a dry brush.
This is to remove all particles that have
not stuck. Now all is ready for the
paint. The first coat should be of red
lead or mineral brown. Red lead must
be bought in dry form and mixed. It is
useless when kept in mixed form.
One or possibly two coats will be sufficient.
For the extra care and pains
taken in preparing the surface and for
securing the right paint, the reward will
be a coating that will be twice or three
times as long-lived as the coating applied
in the ordinary way.
Today the concrete house presents a
problem to the painter. The dull monotony
of concrete requires relief in
color. But it is difficult for the uninitiated
to make the paint film stick. It is
obvious that if the particles of pigment
are to stick they must penetrate an
infinitely large number of pores of the
concrete wall's surface. The pigments
should be mixed with ground cement and
oil. The purpose of the oil is to form
an adhesive, after it has dried out, for
holding the ground particles of concrete
to the broad expanse of concrete wall
surface.
Ordinarily a certain amount of alkali
eventually works its way out of a concrete
surface. The elements eventually
will dispose of this. Some time should
be allowed to elapse therefore, to permit
the concrete to become weatherbeaten
before laying on paint.
Here is an excellent method of preparing
the concrete surface preparatory to
applying the paint. Take equal portions
(by weight) of zinc sulphate and water.
When thoroughly mixed, this solution
should be applied vigorously with a stiff
brush, over the concrete surface. A fine
coating is thus formed. In three days'
time at most, this coat will be hard. The
zinc sulphate incorporates itself with the
paint
CREOSOTED PILING
/"\N the Pacific Coast the problem of
preserving the piles driven in water
is largely that of rendering them immune
to the attack of various marine borers.
It is a field that well could occupy the
attention and time of both construction
engineer and chemist, so great is the
economic loss from this one source
alone. There can be no better time than
now seriously to consider this matter.
Engineers, so far as the experiments that
have been made show, agree upon these
points:
First: Perfect pilings should be
selected, not the cracked, knotted, or
otherwise defective.
Second: Creosote oils, though not
wholly satisfactory," are the best with
wdiich to protect the wood.
Third: These oils should be of the
best.
Fourth: In installation, great care
should be taken to prevent any exposure
of untreated woods below the water line,
where the borers can assail it.
Fifth: Only conscientious experts
should be permitted to oversee the work
in all its stages, from the selection of the
piling to the finished creosoted product.