Friday, February 12, 2010

Milk Paint: Environmentally Safe

Milk Paint is regaining wide usage because it contains only ingredients that are all-natural and will not harm the environment; milk paint is truly a "green paint". Up until the discovery of petroleum and the introduction of toxic chemicals paints were created using natural ingredients such as: linseed oil, lime, casein from milk, turpentine, citrus oils, chalk, and hemp oil.

The formula for milk paint was simple to make and for thousands of years was used throughout the world. Over time different recipes and pigments were tried producing varying results; many of these coatings proved durable while others disintegrated, leaving only a permanent stain on the painted surface. Various recipes included substances such as: olive oil, linseed oil, eggs, animal glue, or waxes.

The oldest painted surfaces on earth were created with forms of milk paint. Cave drawings and paintings were made with a simple composition of milk, lime, and natural earth or vegetative pigments. When King Tutankhamen's tomb was opened in 1924 artifacts, including models of boats, people, and furniture inside the burial chamber, had been painted with milk paint. Until World War II, many Americans still painted houses and furniture with it.

Although major paint manufacturers are now producing more environmentally friendly paints, a good majority of them can still contain hazardous substances. VOC's (Volatile Organic Compounds) belong to a family of chemicals that evaporate quickly and leave an undesirable odor, such as toluene, xylene and formaldehyde, and are main components of modern day paint. They are toxic to humans, particularly children or the elderly, as well as toxic to the environment.

Old-Fashioned Furniture Paint

In the "old" days farmers often used milk as the base for their paint. Any milk that was not consumed could be mixed with some sort of color additive and used as paint. It was once common for household furniture to be painted in this way. Since they had to use regular milk, which was quite thin, for their paint, colored earth and lime would be used to make the paint thicker and to give it some texture. Using powdered milk can control the thickness and texture of today’s milk paint. The directions below explain how it's done.

The pioneer recipes for milk paint had two things in common: milk and lime. Together they form a natural binding agent. Color can be added with any natural substance (rust, berries etc.), water soluble dye, food coloring, or pigments found at arts or crafts stores. Classic red barns are most likely the result of an abundance of milk and the availability of red pigments in the form of rust (iron oxide). Livestock blood was also added to milk to produce blood paint. You can use the recipe below to make your own batch of Milk Paint.

Basic Milk Paint
This recipe makes approximately 1.5 Gallons Milk Paint: good for a bureau or larger project. Cut recipe in half for chair or smaller project.

Ingredients:
1 Gallon Skim Milk
2 Cups Builders Lime also called Hydrated Lime (Do NOT use Quick Lime)
One Quart Boiled Linseed Oil
1/2 Cup of Salt
Add color in as needed.

Directions:
1. First of all, choose a container with a tight-fitting lid. A wide mouth jar works best, but just about any jar will do. Determine how much paint will be blended and choose container accordingly.

2. Begin by measuring Skim Milk into the container. Add salt and lime in small amounts, mixing steadily until all the powder disappears. Don't worry about lumps at this point; continue stirring until the mixture begins to thicken. What makes milk paint so different from more common products is the fact that milk paint is water based. Oil and latex based paints are much thicker than milk paint; keep this in mind as you blend your batch.

3. Add color additives to achieve the desired shade. If other types of natural colorings are desired, check the Internet for lists of various plants suitable for this use. Mix well. Strain if necessary (this is preferred), or you can let sit until lumps rest at bottom of container and use only the paint at the top of the container.

4. The paint will be ready for use immediately. When painting on wood surfaces or furniture, treat it like any other paint. The coloring can often permanently stain clothing that comes in contact with it before it has had time to dry thoroughly, so be careful. Milk paint has a short shelf life, so it makes sense to mix small batches, ideally just enough for your current project. Any leftover paint can be sealed and refrigerated for 3 or 4 days only. Allow the paint to return to room temperature before using again.

If you prefer to use a pre-packaged milk paint products Gallagher’s Milk Paint (www.milkpaintsamples.com) offers 1 oz. Sample sizes.  They offer a brochure and other literature in each “sample kit”. Their samples are packaged as powder and pre-colored.  All you have to do is add water.


Painting

Choose a good quality, polyester or natural bristle brush. Dip the dry brush into water before starting, and then shake out the excess. Wetting the brush helps prevent paint drying in the upper part of the bristles. The first coat won't flow on as easily as you might expect. Let this first coat dry, it will probably be somewhat transparent and full of overlaps.

Before the second coat lightly rub down the surface with steel wool, a kitchen scouring pad, or even very lightly with fine sandpaper. After applying the desired number of coats, give the whole thing a good rubbing with steel wool (#000) then vacuum off the dust. You are now ready for oil.

An easy standard oil blend is boiled linseed oil cut with a little turpentine, a mixture of about 6 to 1 respectively. The turpentine is used as a drying agent. Spread the oil mixture on liberally with a foam brush. When everything is coated, go over those areas that have dried. Let it sit for a few minutes then touch up the dry areas once more. Give it another half-hour or so then wipe away all the excess oil. Cheesecloth is good for this, or a similar soft, absorbent cloth, usually available at the grocery store; any lint left behind can be vacuumed away once the piece is completely dried.

Your project will probably smell slightly of turpentine for a few days, but this will dissipate and should be completely dry in about 24 hours. The result will be a traditional matte finish. This type of milk paint/linseed finish is susceptible to water spots. If a spill is wiped up right away there likely will be no problem. But if left to dry, whitish spots will result. These are easily removed with a little oil/turpentine, rubbed in and wiped away.

There are a number of tricks to think about when using milk paint. One favorite among chair makers is to paint a chair with several coats of different colors - the most common sequence being dark green, barn red and black. Eventually wear caused by repeated use will cut through the various colors, creating the look of old paint that is prized by antique collectors.

Milk paint is very environmentally friendly; you can throw old paint on the ground. Of course, caution should be used to prevent paint from getting in the eyes. Burning may occur because of the lime content. Also, wear gloves if you have sensitive skin. Always wash hands thoroughly with water after painting.

A great article was published in Fine Woodworking that offers photos of all the steps required along with some great tips for the beginner.  Visit www.nrhillerdesign.com/press/pdfs/011199076.pdf

Painting with milk is quickly becoming a rediscovered craft, and it still has something to offer people of all ages. It's safe for the environment, affordable, and can be made with common kitchen ingredients. Pull out that old chair or chest of drawers and mix up a batch of milk paint. Save yourself some money and save the environment while reclaiming or creating beautiful, timeless furniture.

References:
The Real Milk Paint Company, www.realmilkpaint.com

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