CCAT natural paints 2017: Difference between revisions

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Background

It has been almost ten years since CCAT has been painted. The last natural paint project was in 2007: CCAT natural paints and since then some of the walls have faded, cracked and chipped. In spring of 2017, students of Engineering 305: Jonathan, Derek, Tess and Amy will research and develop new natural paint recipes to repaint CCAT.

Problem statement

The objective of this project is to use natural and local materials to repaint CCAT. Through research, development and documentation we will publish our findings and make natural painting more accessible to the general public.

Literature Review

This is a review of the available literature pertinent to the Appropriate Paints Project at CCAT 2017.

Paint Basics

What is paint?

Paint is applied to a surface as a liquid and dries to a solid, called a film. ^[1] Paint is made from a resin/binder, a pigment, and a solvent/thinner; it can also have an extender or additives. ^{[1] [2]} The pigment, usually a powder, gives the paint its color and level of gloss. The binder is a solid that holds the pigment, gives the paint its texture, and makes the paint stick to surfaces. The solvent makes the paint less viscous and easier to spread for application; the solvent and binder together are called the vehicle. ^[1] An extender is an additional pigment that has larger particles.^[1] Extenders help conserve binder and increase the lifespan of the paint film. Additives can be used to modify properties of the paint, e.g. to make it more weather resistant, to reduce drying time, or to make the paint last when stored. ^[1]

Conventional Paints

Pigments and Binders Used

Binders are the component in household paints that make it have a thicker consistency. If binders were not added, the water component would be too strong to adhere to the wall for instance and just drip to the bottom of said surface. Furthermore, the binder, sometimes referred to as resin, is the ingredient that holds the pigment together in a tough, continuous film, and provides film integrity and adhesion. When the binder is mixed with the solvent, the combination is known as a vehicle. The most widely used binders in paints today are: acrylic polymers, alkyd polymers, epoxy polymers. ^[3] To give color to paints, pigments are used. Commonly, inorganic pigments such as white titanium dioxide (titanium(IV) oxide) and calcium carbonate are the most frequent to appear in an ingredient list. Other recurring pigments include: iron oxides to give hues of red, yellow, and black, followed by zinc oxide and carbon black.

Environmental Impact

The impacts from conventional paints have historically come from the choice of solvent. Paint can be water-based or solvent-based. Solvent-based paints use an organic solvent such as benzene instead of water. When solvent-based paints are applied, drying, and curing, the solvent evaporates and releases volatile organic compounds (VOCs) to the environment.^[2] This is what causes the smell that freshly painted walls often have. About 50 years ago, most paints available on the market were solvent-based, but today, up to 80% of paints available are water-based due to VOC regulations. ^[4] In addition to being more environmentally friendly, water-based paints are easier to handle, quicker-drying, and more economic than solvent-based paints. ^[2] Water’s properties (surface tension, density, and thermal conductivity) make it a better solvent than most organic solvents. ^[2]

According to the EPA, the concentration of many VOCs is up to ten times higher indoors than outdoors. ^[5] The agency stresses that while some products may be exempt from VOC regulations because they are safe to use outside, these same products may be health hazards if used inside, and best use practices (e.g. using outdoors or in a well-ventilated area) outlined on product labels should be followed closely. The agency also warns against buying more paint than one needs and storing the excess. ^[5]

The main impacts of VOCs in the atmosphere are ground-level ozone production and human health effects. VOCs react with sunlight and gases such as nitrogen oxides and carbon monoxide to form ozone, which contributes to photochemical smog and the greenhouse effect when generated in the troposphere. ^{[2] [5]} Human symptoms of VOC exposure are nose and throat irritation, eye irritation, headaches, dizziness, nausea, fatigue, and allergic reactions on the skin. ^[5] Long-term, VOCs can cause damage to the central nervous system, liver, and kidneys. ^[5] VOC exposure can exacerbate pre-existing conditions, such as asthma. Additionally, certain VOCs are known to cause cancer in animals and humans. ^[5] Even "low VOC" or "VOC-free" marketed paints consistently emit more VOCs than their labels claim to have in the product. ^[6]

Conventional paint, and many of the products associated with them (e.g. thinners) are classified as household hazardous waste by the EPA and must be disposed of properly. ^[7]

Many materials are used as pigments in paint, but one of the main sources of pigment is titanium dioxide (TiO2). TiO2 must be processed from ilmenite ore, which means it has inherent environmental impacts, such as ozone layer depletion, land use, ecotoxicity, and the indirect impacts from the mining being powered by fossil fuels. ^[8]

Finally, a life cycle impact of conventional paints is that multiple components can come from petroleum, such as the binder and mainly the solvent. This means conventional paints directly contribute to greenhouse gas emissions as well as soil, air, and water pollution by virtue of being petroleum products.

Wall Maintenance in Local Climate (Humboldt County, California USA)

Conventional paints within a controlled environment and applied with correct procedure can last up to five years without maintenance. ^[9] However, there are many real factors that can affect the performance of interior paint making maintenance more frequent and necessary. Humidity is one factor that has a strong effect on interior paint. It can disrupt the function of paint subsequently causing damage to the walls. Exposed to high humidity, interior paints can: alter in color, form deposits, crack, swell, peel and sweat. All of which require a procedure of cleaning and removing of malfunctioning paint, and reapplication of paint with a possible sealer or finish coating.

Appropriate Paints

Pigments and Binders Used

In 2007, the group that did the previous round of appropriate paints at CCAT extensively covered alternative binders; the list has not changed since then, though new recipes exist. The paint options, classified by binder, are flour paint, curdled milk paint, clay paint, egg paint, and oil paint. ^[10] The binders produce differently textured paints, as documented in 2007: the flour paint is thick and textured, the egg and oil paints are velvety, and their milk paint was slightly glossy and more pastel. ^[10] However, judging by the results of different recipes found through research, the consistency of the paint can be slightly different even with the same binder. One instance of using an extender or additive in an appropriate paint was found, which was adding lime and clay or chalk to a curdled milk paint to make it more durable. ^[11]

As for pigments, no evidence was found of successful non-conventional pigments beyond individual claims about certain materials. Some companies claim to sell "natural" or "natural earth" pigments, but there is no definitive information about what the pigments contain. Creating the pigments for the paints using all natural products can be quite difficult. In the 2007 CCAT painting project the pigments used were created mainly from ground up metal oxides or clay. ^[10] For example: yellow from ground up iron oxides, green from chrome oxides, and brown from clay. Pigments can be created from a variety of options. Extraction of color pigments from fruits and vegetables is a viable option. One example of this process involves mixing ground of berries with rubbing alcohol and then filtering and evaporating to leave only the pigment. ^[12]

Wall Maintenance in a Local Climate (Humboldt County, California USA)

Appropriate paints and clay plasters can last a years without maintenance in the right conditions. Often in a home with normal wear and tear, minor damage such as knicks and scratches can expose the wall. In humid climates, it is especially important to maintain the function of appropriate paint and protect the walls from moisture exposure. This entails frequent touch-ups and patching as damage occurs.

Paint Recipes

Flour

Flour paste is used as the binder in some appropriate paints. Carole Crews includes this recipe in her book Clay Culture: Plasters, Paints and Preservation.

White Flour Paste using 4 cups flour: Makes almost 6 quarts Tools: quart jar, measuring scoop, whisk, stove, 8 quart pot, plus a smaller bowl or bucket. Heat 1 gallon water in pot on stove. Pour 5 cups cold water into the empty bowl or bucket and add 4 cups of cheap white flour. Whisk in flour until smooth. When water in the pot reaches a rolling boil, whisk in flour mixture. ^[13] The mix will thicken and look translucent.

This white flour paste is then mixed with clay to bind together the solvent and the pigment. In this recipe Carole adds a few other ingredients for desired look:

Alis Recipe: 6-qt. batch: approx 150 Sq. ft.

Measure one gallon water into bucket. Whisk in: 5 quarts powdered kaolin clay, 2 quarts fine sand and/or whiting, 2 quarts mica (fine flakes or powder), 1 handful of chopped straw (optional), pigment as needed for color (optional), 1 quart cooked flour paste

Mix with a whisk attachment on the end of a cordless power drill. Look for the tacks of the whisk when the mix is thick enough.

Milk

Milk paint recipe with lime added for texture change and increased durability. Includes information about extenders.^[11]

Eggs

Egg Tempera Recipe ^[13]:

First separate yolk from white. Then you can separate the yolk from it's yolk membrane by piercing the yolk and draining the liquid out. Add one teaspoon of water and mix well. Then add this mixture to an equal amount of pigment powder.

Clay

This is a recipe for a fine finish clay plaster that could serve the same function as appropriate paint while also patching cracks or holes that have developed in your wall.

You can separate out clay content from clay-dirt by mixing it well in water and letting it settle for a day. Ladle off the water first and then scoop the very top layer of clay that has separated out from the dirt underneath. Mix 2 parts of this clay with 1/4 part binder of your choice and 3-7 parts of different sized fine sand, whiting or marble dust. ^[13]

Apply thinly (1/8 in) with a fine plaster trowel, let dry and seal with your choice of sealer.

Other

Urban Finish Plaster Using Paper Pulp ^[13]:

Soak shredded office paper overnight or longer and beat it to a pulp. Measure out 1 part squeezed out paper pulp, 1/8-1/4 part starch paste, 1 part fine clay, 0-2 parts fine sand.

This can be used to cover over cracks in the wall surface and can be applied directly over sheet rock. This makes for a good primer layer, or adhesion coat, that you can then cover with your choice of appropriate paint.

CCAT

History

In 1978, the Buck House was set to be demolished yet a group of students petitioned to have the house repositioned as an “experiment with appropriate technologies”. With the backing of HSU faculty and the immediate community, the students began work towards re-appropriating the house for the necessary retrofitting and remodeling. In 1980, the CCAT house was ready for move in and over the nearly four decades since, students have learned much from continuing towards making CCAT *** net zero something or other**** someone help me finish that off please.

Purpose

Many commercial paints include chemicals that contribute to indoor air pollution ^[14]. While many consumers are turning to less pollution causing alternatives, there are still strides that need to be made to reduce the number of greenhouse gas emissions caused by industrial paints. Some retail stores have begun to sell milk paints but many on the market contain more ingredients than if you were to make the paint yourself.

Client Criteria

The Rooms

The second floor of the CCAT building which is also the living space for the three co-directors including Austin Anderson whom will be the only returning co-director for the following year. The living room, dining room, kitchen, and hallway will be the subjected rooms.

The Process of Application

For the kitchen and dining room, which are painted a vibrant yellow and red color respectively, a primer will be used to first to achieve the desired outcome of softer colors. Once primer is finished, we will begin the process of adhering the appropriate paints to said walls. For the living room, which is already a softer color, we will directly apply new coat of paint.

The Colors Wanted

Mr. Anderson, stated that he was happy with the way the previous paints had held up through the years but expressed his desire for lighter colors to help make better use of daylight. Currently the kitchen is a bright yellow, living room has one wall greenish brown while other living room walls are light lavender almost tan color, and the dining room is a darker red. Per request of client, we will aim to go for lighter colors and try to stay away from yellow.

References

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