Lime-casein wash
Lime washes are much more wipe-resistant and durable if whey, fat-free white cheese (quark) or casein powder is added. Quark is obtained when rennet from young cows is added to skimmed milk. This cheese contains 11% casein. Lime, together with casein, forms a chemical waterproofing agent called lime albuminate. Today, the use of cheese is the best solution for lime-casein washes. In traditional lime-casein washes, whey or sometimes skimmed milk was used instead of cheese. Mixtures containing 1 part fat-free cheese, 1 to 3 parts hydraulic lime and 1.5 to 2.5 parts water proved effective. Small amounts of double-boiled linseed oil (not more than 4% of the amount of cheese) increase wipe resistance but reduce the workability of the wash. To get an even emulsion, it has to be well-mixed and stirred from time to time (sometimes every five minutes).
12.1 µ-values of water-repellent loam plasters and sd-values of coatings
12.1
µ-value
Water-repellents loam plasters Clayey plaster (clay = 6%, silt = 6%, sand = 88%) nontreated Wacker, STEINFESTIGER H Herbol, FASSADENIMPRÄGN. HYDROPHOB Indula, HYDROPHOBIN Wacker, BS 15 Metroark, SYLTRIT 1772 Bayer, BAYSILONE IMPRÄGN.-EMULSION Silty plaster (clay = 3%, silt = 18%, sand = 79%)
nontreated Wacker, STEINFESTIGER H Herbol, FASSADENIMPRÄGN. HYDROPHOB Indula, HYDROPHOBIN Wacker, BS 15 Metroark, SYLTRIT 1772 Bayer, BAYSILONE IMPRÄGN.-EMULSION
0.00
Lime, 2 layers Chalk-glue, 2 layers Lime-casein (1: 8), 2 layers Lime-casein (1:1), 2 layers Fat-free cheese, 1 layer Sodium waterglass, 1 layer Lime-casein-linseed oil, 2 layers van Baerle & Co., SILIN, 2 layers Alpina, ALPINA PLUS, 2 layers Auro, BIENENWACHS-STREICHBALSAM, 2 layers Rifa, SILITANIT, 2 layers Linseed oil, 1 layer
0.20
0.40
0.60
0.80
1.00
1.20
Borax-casein wash
Borax can be used instead of hydraulic lime. It reacts chemically with casein in a way similar to lime. With high borax content, crystals form, which can be seen in the wash. Unlike lime, borax does not give a white colour, and is therefore preferable if dark colours are desired. Chalk powder is added in order to make the paint thicker and lighter in colour. A small addition of clay powder increases its workability. If casein powder is being used instead of fat-free cheese, it must be allowed to swell under water for three hours (320 g casein powder in 1 litre of water). Afterwards, 65 g of borax dissolved in 1 litre hot water is mixed into the casein slurry and the whole thinned with 12 litres of water. Colourless casein coating
sd-value Coatings
An even stronger and more wipe-resistant paint is obtained by mixing 1 part hydraulic lime with 5 parts fat-free cheese and 5 parts loam. In bathrooms and kitchens, where greater dry and wet wipe resistance is required, the following procedure is recommended: 1 part hydraulic lime and 5 parts fat-free cheese are mixed without water for about two minutes using an electric mixer. This is allowed to stand for some time, and then 20 parts hydraulic lime, 2% to 4% doubleboiled linseed oil and water are added. Two coats of this wash give a dry and wet wiperesistant surface. Earthen pigments can be substituted for some portion of the lime.
1.40
1.60
0.00 0.00 0.00 0.00 0.01 0.02 0.02 0.03 0.04 0.39 1.22 1.45
In order to retain the natural colour of the loam surface while improving its wipe resistance, a coating of the following mix can be used: 1 part fat-free cheese with 1.8 to 2 parts water and 1/8 to 1/9 part of hydraulic lime powder. This coating will give a colourless to slightly milky surface, with a mild silky sheen caused by its fine crystal structure.
Water repellents Wacker, BS 15, 2 layers Metroark, SYLTRIT, 2 layers Bayer, BAYSILONE IMPRÄGN.-EMULS.LD, 2 layers Herbol, FASSADENIMPRÄGN. HYDROPHOB, 2 layers Wacker, STEINFESTIGER H, 2 layers Indula, HYDROPHOBIN, 2 layers ( ) = Proportion by volume
99
0.00 0.00 0.02 0.02 0.09 0.10
Weather protection
Lime-suet coating
The following recipe from Nepal gives a thick, pasty weatherproof exterior coating: 15 kg of powdered quick lime together with