CASEIN PAINTS. 45 



tion is much the same as when oil paint is used; and the 

 paint itself is stirred in the can at frequent intervals. 



The paint dries very quickly, as smooth as enamel, and 

 in thirty-six to forty-eight hours can be washed and will 

 stand the weather. On account of its elasticity it can be 

 varnished, painted or stencilled on. If applied to a firm 

 substratum, it will neither crack nor peel off; but the surface 

 must be freed from old coatings of lime-wash or distemper 

 before the casein paint is laid on. In the case of oil paint 

 that is still intact, this precaution is not necessary. 



If it is desired to have a glossy paint for indoor use, the 

 painted surface is sprayed over with a liquid mixture of wax 

 and turpentine, which is afterwards polished. 



Notwithstanding their power of standing weather, cold- 

 water paints are porous and do not prevent the circulation 

 of air. On account of their good qualities, these paints are 

 in frequent use both for outdoor use and for interior work, in 

 dwelling-houses, factories, hospitals, etc., as also for coating 

 wood, iron, cement, etc. 



CASEIN PAINT ACCORDING TO AN OLDER METHOD. 



The curd of sour milk is boiled for about a quarter of an 

 hour in a well-enamelled or glazed vessel and then trans- 

 ferred to a sieve where it is washed with cold, hard water 

 until perfectly free from acidity, after which it is wrapped in 

 a cloth and pressed until only a little moisture is left. In 

 this condition it is mixed with one-fourth its weight of burnt 

 lime, previously slaked with a threefold weight of water, 

 the colouring matter, mixed or ground with oil or water, 

 being next added. The resulting paint may be applied to 

 stone, gypsum or zinc, but if intended for use on wood it 

 should be first mixed with 10 per cent, of linseed oil. 

 If too thick, the paint can be thinned down with oil or 

 water. 



