SECRETS OF PAINT AND STAIN CHEMISTRY

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Whether the polymer/binder is natural or synthetic, the medium/solvent in "rubber paint" is ordinary water, which evaporates harmlessly, leaving a thin sheet of paint that won't chip easily, and won't harm any little kids if it does. It will also conform to any shape and stick as tenaciously as chewing gum—which happens to be made from another natural polymer: chicle, the original chewing gum that comes from the milky sap of another tropical American tree.

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The industry continues to reduce individual and environmental hazard; however, in our complex economy, not all paint products can or need be made safe for routine home/amateur use. Artists want and deserve colors that will last for eons, and metallic salts in slow-drying solvents make the most stable pigments. Some can still cause painter's colic, but the danger is common knowledge in schools and artistic circles. Nobody mouths a paint brush anymore. Automotive paints and other industrial finishes still contain components that may be hazardous before or during use, but are perfectly safe to people and the environment if applied as specified—by suitably protected workers in air-recirculating enclosures that capture volatiles for recycling—then allowed to cure under controlled conditions. For example, some industrial paint (such as the red enamel applied to Troy-Bilt tillers) is electrically charged so it sticks like a magnet to oppositely charged metal parts, avoiding a wasteful, potentially airpolluting overspray and creating a tougher finish.

Hi-tech polymer finishes such as DuPont's Imron, which is applied to aircraft and classic autos, U.S. Paint's Awl-Grip yacht finish, or DETCO's Sterling linear polyurethane used on boats, outdoor furniture, and buildings, are created by onsite mixing of separate components similar to the resin/hardener mix used in the fabrication of fiberglass or epoxy glues. The base components of the bivalent compound may be harmfully volatile or caustic alone, but they combine to harden into a surface protectant that is benign and stable, and that encapsulates any potentially harmful pigment in an impervious plastic sheath once it is dry and cured.

Professional house painters use full-body protection and respirators when needed. But you won't need to. Modern house paints—both wall/ceiling coverings and hard enamel for woodwork—from Sears, Sherwin-Williams, Glidden, other national brands, and smaller regional paint manufacturers—are wonders of modern polymer paint chemistry.

You've seen, and most likely used, the "color centers" in hardware stores and home improvement centers where hundreds of shades of latex house paint can be mixed automatically. Exterior paint is still best applied to a carefully scraped, caulked and primed surface with good-quality brushes (by professionals with the ladders, staging and experience to do it right and safely).

But interior wall and ceiling painting is a do-it-yourself job, since modern finishes almost apply themselves with rollers, flat-foam crack-and corner applicators and disposable foam brushes. Some wall paints even incorporate an airtight moisture barrier for better heating efficiency. The modern latex replacement for white-lead/linseed oil enamel is as hard and glossy as its predecessor, but is harmless in all forms, and in drying, smells to me like a faint air freshener.

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