02 February 2013

Don't cry over spilled milk...make paint instead!

Milk paint, also called casein paint, is actually made from the curds of the milk, so first you sour it to separate the curds from the whey. (See instructions below.) Milk-based paints work well on a variety of absorbent surfaces, such as drywall, clay plaster, clean wood, or paper. The resulting paint has a slight sheen. It is wipable with a damp cloth but not scrubbable, so don't use it on surfaces that get scrubbed clean. That said, if you use milk paint on wood, you can then seal the wood with tung oil or linseed oil for an incredibly beautiful and durable finish. This is a great paint to make with kids!  My niece likes to paint with milk paints when she visits.
paint samples of various milk paint colors (left side is semi-opaque, right side is translucent)
To make the curds...
To separate the curds from the whey, you basically are souring milk. You can do this one of two ways:  1) let your milk stand in a warm place for several days, undisturbed, and with the lid slightly off OR 2) you can speed the process up by adding 1/2 cup of white vinegar or lemon juice per gallon of milk. The key is to leave the milk completely undisturbed in order for the curds to develop into large particles. If you shake or stir the milk while it is souring, the curds become small and difficult or impossible to strain out. There is a fabulous instructional video online at: http://www.youtube.com/watch?v=nb2pE6Ge-0Q

I have had the best results with 1% or 2% milk, but theoretically any milk will work. Once your milk has soured and separated, you will see white chunks floating over a clear yellowish liquid. This means your milk is done! Strain the curds through a fine strainer or in cheese cloth to discard the liquidy whey. If you are painting walls, I recommend rinsing the curds in cold water a few times to remove any residual whey.

To make milk glaze...
...a translucent pigmented glaze that will cover approximately 40 SF
1 cup strained milk curds (see above)
1½ Tablespoon borax (such as 20 Mule Team, available in the laundry aisle of most supermarkets; optional but I always add it if I'm painting a wall)
¼ cup hot water
approximately 2 Tablespoons pigment (or as desired)
Dissolve the borax completely in the hot water.  Then slowly whisk into the strained milk curds. Stir thoroughly until lump-free. Add pigment to the desired color. This will make a translucent glaze-type paint. If you want to make an opaque paint, you can add 1/2 cup whiting (purchased from an artist supplier and soaked in water overnight) to the recipe above.  Tip for adding pigment:  you can soak your pigment in water overnight and then strain it through cheesecloth if you want to be sure all of your pigment gets fully dissolved in the paint.


To make milk paint...
...an opaque pigmented paint that will cover approximately 20 SF


1 cup strained milk curds
1½ T borax
¼ cup hot water
2-3T (35g) pigment (or as desired)
½ cup (100g) whiting* (soaked in cold water for 24 hours)
Dissolve borax in hot water & allow to cool.  Add borax mixture to strained milk curds & stir thoroughly.  Add whiting & pigment to desired color.  Can be thinned with additional water.  Apply in thin coats, allowing each coat to dry between, or the paint will tend to crack or flake off.

*whiting is high grade calcium carbonate made from finely powdered chalk that can be purchased from any artist supply shop; it is what makes the milk paint opaque.


To paint with milk glaze or paint...
Use any standard application technique: brush, roller, or sponge.  The translucent glaze can be layered with complimentary colors. Apply the paint in thin coats, allowing each coat to dry completely (about 1 to 2 hours).


Resources
For more general information about natural paints, and links to other natural paint recipes, see our previous blog post: Paint it Green!...with natural paints


I included this book in my last post, but it really is by far my favorite book on natural paint.  The format resembles a cookbook...recipes on one side and a photo of what the paint looks like on the other.  This book contains tons of information and inspiration.
click cover for more info or to purchase

18 comments:

  1. What a great blog, and where from you get so much nice information and experience in this field. Window cleaning wellington

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  2. This link
    http://www.earthpigments.com/video/quark/making-quark.cfm
    is no longer available.

    Just thought I'd let you know.

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    Replies
    1. They moved the link to here: http://www.youtube.com/watch?v=nb2pE6Ge-0Q I changed it in the original post as well. Thanks so much for letting me know!

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  3. Gracias Sigi!
    I ordered the book and just made the first batch of paint for my daughter's adobe house. Finding the calcium carbonate may prove challenging, so glaze may have to do. We teach natural,building here on the beach in Mexico. Wattle & Daub, traditional Adobe, Compressed earth blocks and Cob so far. Would love to have you visit the ranch, perhaps teach a workshop. www.ranchosolymar.com.

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    Replies
    1. That's awesome! Milk paint is really addictive & fun :) If you want the paint to be opaque, you can add whiting (finely ground chalk) or you can do multiple layers until you have the look you want :)

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    2. ps. a workshop in Mexico would be fun :) :) :)

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  4. Hi Sigi,
    Can I use milk glaze over lime washed/pigmented cob walls? I'm not sure if the lime would react with the milk. Thank you!

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    Replies
    1. that's an excellent question, and I'm not sure the answer. Theoretically yes, it should be fine. But I would do a test area first to make sure. (And note that milk paint/glaze is only suitable for interior applications)

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  5. This comment has been removed by the author.

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  6. Your blog is an oasis in the desert! haha I've been searching and searching for just this for a while now and was just about to give up. I love how detailed and well explained these recipes are. Thank you! Really, I appreciate your work and will be a devout follower of your site from now on!
    Would love to have a natural paint workshop in Cabo, BCS, México, where I live!
    All the best,

    Maria

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  7. Sigi, what I can use instead of borax?

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    Replies
    1. the borax is optional, so you can just skip it :)

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    2. the borax kills bacteria and is generally an anti-microbial additive. It also somewhat helps the solubility of the curds when you thin with water.

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  8. Hi- I have some quark I made about a month ago (on the counter method)- it has been in the fridge and doesn't have mold nor does it smell "off"- do you think i can still use it to make milk paint ? Thanks! :)

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