LIMEWASH THAT LASTS

Wairarapa Times-Age, 31 October 1938, Page 3

LIMEWASH THAT LASTS

TRIED FORMULAS FOR FARMS. Common limewash, made by. slaking freshly burnt lime and diluting it with water, is often found to be friable when dry, and rubs or flakes off rather easily. Effort has, therefore, long been directed to the discovery of a method of preparation which will make the coating more resistant to rubbing, less liable to flake off, and having some waterproofing qualities.

At the start, it should be said that a good deal of the flaking which occurs is due to new coats being put over previous applications which are practically already detached from their base, and merely require the slight “pull” caused by a succeeding coat to cause them to break. There is no known way of overcoming this condition other than removal by washing or scraping of the defective coating. Ordinary limewash is made by slaking about 101 b of quicklime with two gallons of water. As an ordinary fixative, alum, loz to the gallon, will stop whitewash from rubbing off easily. FLOUR PASTE. Alternatively, the addition of flour paste, which, however, needs the further addition of zinc sulphate as a preservative to prevent mildew, may be tried. A reliable recipe for interior use (walls, ceilings, etc.) is:—(a) 621 b (one bushel) quicklime, slake with 15 gallons of water and cover with sacking till steam, ceases to rise. Stir occasionally to prevent scorching; (b) 2| 1b rye-flour, beat up in half gallon cold water, then add two gallons boiling water; (c) 2Jlb common rock salt dissolved in 2£ gallons hot water. Mix (b) and (c), then pour into (a) and stir until well mixed. This produces a mixture of good brushing consistency and is used iri factories, being recommended to prevent easy ignition. WEATHER-PROOFING COATING Where a weatherproof coating for use out-of-doors is required, the following is a recipe which should prove satisfactory:— Place one bushel of good fresh quicklime in a barrel with 201 b of beef tallow, • slake with hot water (about 15 gallons added gradually so as not to “drown” the lime) and cover with sacking to keep in steam. When the lime has slaked the tallow will have disappeared, having formed a chemical compound with the lime. Dry colours (ochre, sienna, etc.) may be added before slaking if a cream or buff Tint is desired. The mixture should be stirred occasionally, and thinned to easy-flowing consistency with clear water when cold.

“Lighthouse” whitewash, again suitable for exterior purposes, is made in the following way:—(a) 621 b (one bushel) quicklime, slake with 12 gallons hot water, (b) 121 b rock salt, dissolve in six gallons boiling water; (c) 61b Portland cement. Pour (b) into (a) and then stir in (c) and use at once.