Civil Engineering Reference
In-Depth Information
Glue paint recipes
Glue paint should not be used in bathrooms or similar areas, or on surfaces exposed to a
great deal of wear.
When painting on render it is usual to soap the surface with a thin solution of green
soap, consisting of 2 dl green soap to 10 litres of water. This has to sink in and dry in order
to give the glue paint a chance to penetrate evenly into the render. Painting can begin
when the surface is dry.
Painting should be done wet-on-wet so as not to cause stains. The pigment should be
mixed with a little water to a thick colour paste with no lumps.
Recipe: Glue paint based on bone glue and skin glue (10 litres)
The ingredients are 200 g bone and skin glue and a little water, with 5 litres of water, 10 kg
of painter's chalk and pigment. The paint is prepared in the following way:
1.
The chalk is first soaked, in a bucket for example, and left to stand overnight without
stirring.
2.
The glue is made. Bone and skin glue should be left to soak in a little vessel
overnight, with water just covering the glue. The glue should then be warmed in a
water bath until it floats.
3.
The glue solution should be poured into the chalk and the mixture stirred well with a
whisk.
4.
The pigment should be stirred into lukewarm water then added to the glue and chalk
mixture. Certain fatty pigments are not easy to dissolve, but this can be improved by
adding a teaspoon of alcohol, which breaks down the surface tension. The stronger
the colour required, the more chalk must be replaced by pigment.
Casein paint
This is used mainly in emulsion paints. Milk protein is used for binding, and will react to a
certain extent with surfaces containing carbon to lime casein, which is waterproof. Pure
casein products are not waterproof and must be used indoors. (See also 'Recipe 4: Lime
casein paint', p. 414.)
Drying oils
A drying oil dries in the air, at the same time keeping its elasticity. The most com-
mon and the best is linseed oil, but even Chinese tree oil and hemp oil make good
quality paint. To some extent soya oil, olive oil and fish oil can also be used, but
these are not actually drying oils.
Linseed oil dries by oxidizing in air and is transformed to a strong and solid
linoxine. This oil has been used in painting since the beginning of the seven-
teenth century and can be used on wood, concrete, render and to a certain extent,
