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Whitewash is slaked quicklime, at times
combined with pigment. It dries
through crystal formation. In combination with a proteinaceous
(protein-based) binder, quicklime (or inert lime) is not a
whitewash but a water-based, water-soluble paint -- usually
a distemper, calsomine or milk paint.
Whitewash has been used for millennia. It is
found as a major treatment in 17th- to early 20th-century
houses as a wall and ceiling treatment; on wood, plaster,
and masonry; for protection, sanitation, and as a decorative
treatment. While a paint, whitewash is prepared -- and usually
used -- by masons, as the process of making whitewash involves
slaking quicklime, employed for
mortar and cement.
"Whitewash. An inexpensive white coating
for rough work on walls or ceilings. It is neither permanent
nor waterproof. The term usually refers to lime mixed with
water, but calcimine and other cheap water paints may also
be called whitewash. Whitewash has been used in the past to
impose artistic censorship by hiding mosaic and fresco mural
decoration for religious and political reasons. Many such
works have been reclaimed in modern times, by simply washing
away the coating."
Mayer, Ralph, Dictionary of Art Terms and Techniques,
New York: Barnes & Noble Books, 1981, first published
in 1969, p.431.
"Whitewash: white fluid commonly used
as an inexpensive, impermanent coating for walls, fences,
stables, and other exterior structures. It varies in composition,
being generally a mixture of lime (quicklime), water, flour,
salt, glue, and whiting, with other ingredients such as molasses,
water glass, or soap sometimes added. Mixed with size and
colored, whitewash is occasionally used on interiors as calcimine."
The Columbia Encyclopedia, Sixth Edition, 2000.
The folowing recipes are cited from Nineteen Ninety Five
Paint Questions Answered, New York: The Painters Magazine,
1270 Whitewash for Interior Walls and Ceilings, p.462
A.B., New Bedford, Mass., writes:- I
should like to have some information regarding interior
whitewashing. I whitewashed some ceilings with good slaked
lime that was slaked for two or three days before. The first
coat worked all right, but the second coat crawled and spotted
all over the sidewalks [sic], and yet the third
coat was again all right. In another case I had the ceiling
peeled a day or two after it was dry. Can you account for
Answer:- Always slake your lime with boiling
water and cover the tub or barrel with sackcloth or burlap
to keep the steam. When the lime has all broken up keep
it covered with water; never let it dry up., for then it
becomes useless. After you have thinned down your slaked
lime to the right consistency for application add two more
tablespoonfuls of salt to each pail of the wash, also one
pound of flour, previously mixed with hot water, stirring
it thoroughly. This will give good binding property to the
wash and keep it from peeling, nor will it rub off when
dry. If the wash is to be thin one-half pound of flour to
the pail will be sufficient, especially when it is going
on a sandy wall.
If the whitewash works poorly or comes
out spotted. one ounce of potash alum dissolved in water
and added to a pail of whitewash will correct the trouble,
but too much alum is liable to make the whitewash scale.
A good, hard drying whitewash that will not crack or peel
can be made by slaking thirty pounds of builders' lime with
hot water, keeping in the steam for at least twelve hours.
When diluted add to the wash two pounds of zinc sulphate
and one pound common salt previously dissolved in water.
It is not good practice to use glue as a binder for whitewash,
and at any rate if the glue is not first class or has not
been dissolved thoroughly, it will make the wash crawl and
spot as you have stated. If you have to whitewash any surface,
wall or ceiling that has been greasy it is best to wash
it first with vinegar before applying the whitewash. It
is an important point that brushes, pails, etc., are clean,
and the wash should be strained.
#1259 - Whitewash as Specified by the U.S. Government,
The recipe for mixing whitewash according
to government specifications was wanted.
Take of fresh Rosendale cement 3 parts
by measure, of clean, fine sand 1 part by measure, mix with
fresh water very thoroughly. This makes a sort of granite
color, dark or light, according to the color of the cement
and sand. If the color is desired nearly white, use two
parts fresh lime, slake this first, then add 1 part cement
and 1 part white sand. For a brick red color, Venetian red
is added first to the mixture; for buff color yellow ocher
is added. The wash must be made as thin as can be conveniently
applied with a whitewash or large kalsomine brush. Before
applying the wash, the surface must be wet with clear water,
so as to give the wash an opportunity to hold out until
it sets. It is admirably adapted for brick and stonework
or rough fences, but will not work over paint or whitewash.
It should be kept well stirred during application.
#1257- Whitewash for Exterior Surfaces, p.458
Take one-half bushel of freahly burnt lime
and slake it with boiling water, cover it over during the
slaking so as to keep in the gases that are generated. Sift
the mixture through a fine sieve, and add to it seven pounds
of salt previously dissolved in sufficient warm water; three
pounds of ground rice boiled to a thin paste and stirred
in boiling hot , half a pound of powdered Spanish whiting,
one pound of glue (which has previously been dissolved by
soaking it well and then heating it in a glue pot); add
five gallons of hot water to the mixture, stir it well,
and let it stand a few days covered free from dirt. It must
be put on quite hot; for this purpose it can be kept in
a vessel over a portable furnace. About one pint of this
wash will cover one square yard.
A simpler whitewash is prepared by mixing to
a batter half a pound of wheat flour with cold water, and
making it into a paste by pouring on it boiling water to
thicken it, a pour this paste into a pailful of lime and
water which has been mixed in the ordinary way of whitewash.
Stir it all well together.
A formula used by the United States Government
in making whitewash for light-houses and other public buildings
is as follows:
Unslaked lime...... 2 pecks
Common salt....... 1 peck
Rice flour........... 3 pounds
Spanish whiting... 1/2 pound
Glue (clean and
white.............. 1 pound
Water, a sufficient quantity.
Slake the lime in a vessel of about 10
gallons capacity; cover it, and add the salt previously dissolved
in warm water. Boil the rice flour in water; soak the glue
in water and dissolve on a water bath, and add both, together
with the whiting and 5 gallons of hot water to the mixture,
stirring all well together. Cover to protect from dirt, and
let it stand for a few days, when it will be ready for use.
It is to be applied hot, and for that reason should be used
from a kettle over a portable furnace.
General Directions for Preparing Whitewash.
In general, virtually any type of quicklime or
hydrated lime may be used in the preparation of lime paste
with the following formulas. However, generally hydrated lime
is preferable, but when hydrate is used best results are obtained
from the more highly refined types of commercial hydrates
which contain virtually no coarse particles or lumps. Specifically,
these more refined types of hydrated limes are known as chemical
hydrate, agricultural spray hydrate, finishing lime, and pressure
hydrated lime. The use of such limes is particularly important
when the whitewash is to be applied with a spray pump or paint
gun in order to prevent the nozzle on the sprayer from being
clogged. Otherwise, it is necessary to strain the lime paste
made from quicklime and unrefined hydrated lime through a
fine screen in order to remove the coarse particles. In any
event, it is always advisable to follow the lime manufacturer's
directions on slaking the quicklime or soaking the hydrated
lime. Approximately 8 gallons of stiff lime paste are produced
by slaking 38 pounds of quicklime with 8 gallons of water,
or by soaking 50 pounds of hydrated lime in 6 gallons of water.
After water is added to the mix the final whitewash
mixture should be thin, resembling the consistency
of whole milk.
While lime alone with water for whitewashing
can be used in some instances, the durability of such a mixture
will generally be improved by adding other materials to the
mix. The following formulas are divided into two groups: (1)
those formulas which are simpler to prepare, but which have
produced satisfactory results and (2) more detailed formulas
which are satisfactory and may even produce better results
than those listed in the first group.
I. Simpler Formulas
1. Salt........................15 lbs.
Lime paste.................8 gals.
Dissolve the salt in about 5 gallons of water and add
this solution to the lime paste. Mix thoroughly and thin
to desired consistency with fresh water.
2. Calcium chloride (dry)...5 lbs.
Lime paste.................8 gals.
The substitution of calcium chloride for the salt in
formula (1) produces a mixture that does not chalk and
is quite durable. The same mixing directions apply.
3. White portland cement...25 lbs.
Hydrated lime.............25 lbs.
Both the cement and lime should be
added together in dry form to about 8 gallons of water.
After mixing thoroughly a thick slurry will result. Additional
water should then be added until after further agitation
the mixture resembles the consistency of heavy cream.
Do not mix more than can be used in a few hours.
Note. The above weight proportions are approximately
equivalent to one part of cement to 2 parts of lime by
II. More Detailed Formulas.
4. Casein......................5 lbs.
Household water softener
(Trisodium phosphate).3 lbs.
Lime paste................8 gals.
Soak the casein in about 2 gallons
of hot water until thoroughly softened (about 2 hours).
Dissolve the water softener in 1 gallon of water, add
this solution to the casein, and allow the mixture to
dissolve. Dissolve the formaldehyde in 3 gallons of
water. When the lime paste and the casein solution are
thoroughly cool, slowly add the casein solution to the
lime, stirring constantly.
Just before using slowly add the formaldehyde
solution to the batch, stirring constantly and vigorously.
Care must be taken not to add the formaldehyde too rapidly
as this may cause the casein to form a jelly-like mass,
thus spoiling the batch. Do not make up more of this formula
than can be used in one day as it may deteriorate.
This formula is recommended highly for most
uses, as the coating is white and is quite weather-resistant.
5. The addition to 1 to 2 pounds of calcium chloride to
formula (3) will improve the results slightly. The calcium
chloride should be dissolved in a small amount of water
and added and stirred into the cement-lime mix just before
6. Skimmed milk.............5 lbs.
Lime paste.................8 gals.
This formula is a favorite of some
dairy farmers for whitewashing the walls and ceilings
of barns. Here, skimmed milk largely replaces water as
the solvent. After mixing the skimmed milk thoroughly
with the lime paste, add the formaldehyde slowly, stirring
vigorously. Add water until desired consistency is obtained.
8. Casein......................5 lbs.
Lime paste.................8 gals.
Soak the casein in 4 gallons of hot water until thoroughly
softened (about 2 hours). Dissolve the borax in 2 gallons
of water and add this solution to the casein. When both
are cold, slowly add the borax-casein solution to the
lime paste, stirring constantly and vigorously. Thin to
the desired consistency. Do not prepare a larger quantity
of this formula than can be used in one day as it may
9. The addition of 1-1/2 to 2 pounds of titanium dioxide
or zinc sulfide (opaque white pigments) to any of the above
formulas will improve the appearance of the whitewash when
it is wet as well as help to retain the "dead" white effect
for longer periods. The opaque white pigment should be mixed
thoroughly with the lime paste.
Applying the Wash.
Whitewashes and lime paints should be
applied thin, and the surface should be dampened so that
the coating will dry gradually. In fact, best results
will be procured if the application is so thin that the
surface to which it is applied may be seen easily through
the film while it is wet. The coating will dry opaque, however,
and the thin coat will give better results than a thick
one. A second thin coat may be applied over the thoroughly
dry first coat if a whiter surface is desired. These
cold water preparations can be applied easily and satisfactorily
with a large brush. Do not attempt to brush out the coating
as is done with oil paint, but simply spread it on as evenly
and quickly as possible. The whitewash should be stirred
frequently while it is being applied to prevent settling.
Whitewash & Cold Water Paints, Washington, DC: National
Lime Association, copyright 1955, 15 pp., ref: pp.5-8.