Whitewashing has been frequently referred to in the foregoing pages as
the most suitable treatment for the exterior of chalk and earth
buildings.
There is, however, a certain prejudice against lime-whiting amongst both
owners and occupiers, owing to the frequent renewal that its adoption
usually implies.
With a view to removing this drawback from a treatment otherwise so
effective, the following recipes are suggested as improvements on the
usual practice.
Ordinary whitewash is made by slaking about 10 lbs. of quicklime with
two gallons of water.
The following recipes are taken from "_White Paints and Painting_"
(Scott), and are reliable:
(1) "_Factory" Whitewash (interiors), for Walls, Ceilings, Posts, etc._:
(_a_) 62 lbs. (1 bushel) quicklime, slake with 15 gallons water.
Keep barrel covered till steam ceases to arise. Stir occasionally
to prevent scorching.
(_b_) 2-1/2 lbs. rye-flour, beat up in 1/2 gallon of cold water, then
add 2 gallons boiling water.
(_c_) 2-1/2 lbs. of common rock-salt, dissolve in 2-1/2 gallons of hot
water.
Mix (_b_) and (_c_), then pour into (_a_), and stir until all is well
mixed. This is the whitewash used in the large implement factories, and
recommended by the insurance companies. The above formula gives a
product of perfect brush consistency.
(2) _"Weatherproof" Whitewash (exteriors), for Buildings, Fences, etc._:
(_a_) 62 lbs. (1 bushel) quicklime, slake with 12 gallons of hot
water.
(_b_) 2 lbs. common table salt, 1 lb. sulphate of zinc, dissolved
in a gallon of boiling water.
(_c_) 2 gallons skimmed milk.
Pour (_b_) into (_a_), then add the milk (_c_), and mix thoroughly.
(3) _"Light House" Whitewash_:
(_a_) 62 lbs. (1 bushel) quicklime, slake with 12 gallons of
hot water.
(_b_) 12 gallons rock-salt, dissolve in 6 gallons of boiling water.
(_c_) 6 lbs. of Portland cement.
Pour (_b_) into (_a_), and then add (_c_).
* * *
_Note._--Alum added to a lime whitewash prevents it rubbing off. An
ounce to the gallon is sufficient.
Flour paste answers the same purpose, but needs zinc sulphate as a
preservative.
The following are from "_1,000 More Paint Questions Answered_":
(4) _Durable Whitewash for Outside Use._--A whitewash that will not rub
off or wash off in rainy weather can be made by mixing one half-pint of
flour to a batter with cold water, then stirring into this boiling water
until it becomes a thick paste.
While still hot it is poured into a pailful of ready-made lime whitewash
and well stirred in.
(5) Another simple method is to add to 2 gallons of ready-made lime
whitewash one half-pint each of molasses and table salt. Must be stirred
frequently while being used.
_Whitewash for Exterior Surfaces._--A formula for a durable whitewash
for out-buildings of rough lumber. The following is reprinted from
"_Popular Mechanics_":
(6) Place 1 bushel good fresh lime in a barrel with 20 lbs. beef tallow;
slake with hot water and cover with sackcloth to keep in steam. When the
lime is slaked, the tallow will have disappeared, having formed a
chemical compound with the lime. Dry colours may be added to produce any
tint desired.[10]
[Footnote 10: Experiments and tests carried out for the author
by the Department of Scientific and Industrial Research place
this receipt at the head of the list.]
It is better to add colour before slaking the lime, but if this is not
feasible mix the colour with alcohol and add it to the strained
whitewash. Thin to easy flowing consistency with clear water.
[Headnote: Distempers and Limewashes]
_Cold Water Paint that will stand the Weather._--A formula for making a
white outside coating that will resist the action of the weather and
remain hard even under the influence of moisture and rain. Experiments
with different brands of cold water paints have proved failures.
A really effective cold water paint, in order to resist the elements and
remain white, should contain a white pigment of good body and some oil
in addition to the water, and with this purpose in view the following is
suggested:
(7) To make 100 lbs. of such paint, mix 10 lbs. white, pure in oil, with
10 lbs. bolted whiting, 8 lbs. raw linseed oil, 6 lbs. soft soap (made
with potash), and 26 lbs. soft water.
One quart of pale copal varnish will improve the preparation. The
formula given is of the right consistency to apply on dressed lumber
with the brush. For application on rough lumber or with the spraying
machine it requires more thinning with water and varnish.
The following is taken from Pearce's "_Painting and Decorating_":
(8) A London recipe for distemper has the following proportions:
4 "balls" whiting, 2 lbs. Young's patent size, and sufficient water to
cover the whiting.
(9) A Scotch distemper is described as: 12 lbs. whiting, size as given
previously, 2 ozs. alum, 2 ozs. soft soap. It is very fast, for
passages, schools, etc. Tinting colours for limewash should be
restricted to ochres, umbers, lime blue, lime greens, charcoal or lamp
black, and earthy reds (as Venetian).
(10) External limewash for farm buildings, etc., may be made as follows:
Lime, 1/2 bushel, slaked with 1 gallon of milk and remainder of water,
1 lb. salt and 1/2 lb. sulphate of zinc to make it withstand the
weather.
Experiments with and practical tests of these and other kinds of
whitewash are being carried out, and the author hopes that he may find
opportunity at some later date of announcing the results obtained.
[Headnote: Local Materials]