Milk Paint 
| Milk Paint |
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| Written by Leon | |||||
| Thursday, 10 February 2005 | |||||
Make your own paintWith cheap, non-toxic ingredients
The average tin of paint from the hardware store is a cocktail of chemicals with names that only a chemist could love. While some are benign, many are definitely best avoided. The toxins in common housepaints include cadmium, mercury, phenols, chlorine, sulphur, formaldehyde and other volatile organic compounds. These can all cause illness for both the painters and the people who live with the painted surfaces-ranging in severity from headaches and nausea through to cancer. ReNew and Soft Technology have run articles on non-toxic paint alternatives, but many people are put off by the extra cost of non-toxic paints (even though the avoided health costs may make up the difference). Paint also has a high energy cost. Today's conventional paints are, by weight, among the most energy intensive building products. Many of the non-toxic alternatives available in Australia are made in Europe, which means they must be shipped here, adding to their associated greenhouse gas emissions and other pollutants. So where to get the least costly, non-toxic, low-energy paint? The answer lies in a trip to the milk-bar. A couple of litres of skim milk will form the base for enough paint to begin experimenting. The next stop is the hardware store for some builder's lime (also called slaked or hydrated lime) and plaster of Paris. Apart from some water and your choice of pigment, these are all the ingredients you will need. There are several variations on what is usually referred to as `milk paint'. One involves mixing lime into a thick paste with a little water, then gradually adding milk until it reaches a paint-like consistency. I was told about this method by a friend of mine, Salvatore, who had used it while growing up in Italy in the 1930's and 40's. Both ingredients were widely available, and used with various pigments, milk paint is attractive and durable. I tried the recipe using bottled skim milk, though Salvatore recommends milk directly from the cow, with the cream skimmed from the top.I sieved the lime before mixing it with the milk, and let it sit for several hours, though found that it was still quite lumpy. Straining the mixture through muslin makes it much smoother. I used the paint on old unpainted weatherboards, and got good coverage-once it dried it actually looked like paint! An internet search revealed some other paint recipes. One that I tried consists of plaster of Paris as the main solid ingredient, mixed with a little lime and skim milk. Again, filtering through muslin cloth to remove lumps is a good idea. This paint was similar to the lime paint, but where the lime-only paint was powdery when dry, the plaster of Paris set a lot harder. Creating colours
There are many options for colouring milk paint. For a straight white, zinc oxide or titanium dioxide are good. Calcium carbonate or chalk will make the paint more opaque. Iron oxide (rust) is easy to manufacture at home from steel wool or iron filings, and gives the paint a nice ochre colour. Many traditional paints used wild berries for colouring. Again, the muslin cloth comes in handy for removing pips. If you're concerned about being able to replicate your colours, you could compromise and buy some ready-made pigment from an art supplies shop. Cleaning up Finishing the surface What the ingredients do Commercial milk paints
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| Last Updated ( Tuesday, 27 September 2005 ) | |||||
