Five myths about house paint
Originally published in the Santa Cruz Sentinel, April 9, 2011
My kitchen chairs are old, purchased when my family was young, along with a matching table. They are natural pine, coated with clear varnish, and—after 15 plus years—an additional layer of grime and wear. Rather than strip and refinish, I decided to paint my chairs using lots of color; and, in the process, I learned a lot about paint.
The problem with painting over old varnish is that paint won’t stick to a shiny surface. If the varnish is so old that it’s lost its shine, painting directly over the varnish might work. But it’s a better bet to give the surface some “teeth” by sanding the varnish first with fine grit sandpaper, and then applying a coat of white primer before painting.
Myth #2: You should always use oil-based paint on furniture, and in kitchens and bathrooms
In California, all house paint sold today is water-based (commonly called latex), since oil-based house paints were banned because they contain toxic solvents. (The only exception is paint designed for special purposes, like RustOleum for metal.) Water-based products are less hazardous, clean up easily with warm water and soap, and perform well in high-use or damp environments like kitchens and bathrooms. They dry quickly, but take about one week to really cure to a final hardness.
Primer, on the other hand, comes in water-based and oil-based versions. Oil-based primer dries slower but harder and is typically more resistant to moisture and wear. It will also adhere more reliably to an oil-based surface like varnish. Oil-based primer contains strong-smelling solvents and preservatives such as formaldehyde and benzene, which are flammable and carcinogenic, and require more solvents for clean-up. If you use oil-based primer, work safely and do all your painting and clean-up outdoors or in the garage with all the doors and windows open.
|My daughter, Quin, started painting her kitchen chair|
with a more intricate design.
Myth #3: Paint can labels will help you choose the right paint
Go to three different paint stores and try to compare paints just by reading labels. It can’t be done. Labels on paint cans can be inconsistent, incomplete and misleading. Here are two examples:
Enamel, which used to mean oil-based, now means water-based paint with some amount of sheen. The greater the sheen, the more scrubbable the surface. There is no industry standard for paint sheens, so one company’s eggshell can be another company’s satin, matte or low gloss. The confusing array of enamel finishes includes matte, velvet flat, pearl, low luster, eggshell, satin, mid-luster, low gloss, semi-gloss, gloss and hi-gloss.
Acrylic is a synthetic polymer (plastic) found in most water-based paints. Acrylics improve paint quality because they are more resistant to staining, mildew, cracking, peeling, and blistering. Latex house paints tend to be a “co-polymer” blend of binders (acrylic, vinyl, PVA and others), filler, pigment and water. Paint labels typically will not reveal the percentage of acrylic (or any other ingredient) used in a latex paint. Some do not list the ingredients at all.
Myth #4: Latex paints contain latex, oil-based paints contain oil
Natural latex comes from the sap of tropical trees, and is used to make rubber gloves, swim caps and condoms. Latex paint is a synthetic version of natural latex. There is no natural latex in latex paints. Oil-based paint is an alkyd resin base thinned with mineral spirits (paint thinner) and contains no oil.
Myth #5: Only oil-based paints are hazardous
VOC stands for Volatile Organic Compound. The VOC rating shows the level of emissions generated by the product over time and at the time of application. Oil-based paints, which have the highest level of VODs, can trigger asthma attacks, create throat and eye irritation, nausea and headaches. Long term exposure can lead to cancer, kidney and liver disease. However, most latex paints also contain VOCs, so take warnings such as “USE ONLY WITH ADEQUATE VENTILATION” seriously. In general, flat, pastel paints have lower VOC levels than bright, high-gloss paints. Large paint companies such as Sherwin Williams and Benjamin Moore carry a line of zero VOC paints.
Milk paints are a re-creation of a very old paint formula which are made from natural ingredients such as curdled milk, lime and pigment, and have no VOCs. You can mix your own milk paints, or buy them in a powdered form, but once mixed, they need to be used quickly before they spoil. Frequently used on furniture, milk paint is valued for its saturated colors, durability and antique look, as well as its environmental friendliness. Don’t be fooled by cans of pre-mixed paint labeled “milk paint” which are actually a synthetic version of the traditional milk paint colors, but not the safe formula. Greenspace on Soquel Avenue in Santa Cruz carries powdered milk paints and other paints that are low-odor and low or zero VOC.
|To transform an inexpensive plastic chair|
local artist Linda Levy teaches decoupaging.
Local artist Linda Levy teaches workshops on decorating outdoor plastic chairs, but has also painted many wooden chairs in her time. “For any surface,” she says, “you have to prepare it first.” The best preparation is to remove any dirt with steel wool and then sand with a fine-grit sandpaper. “For a hard, smooth finish, the finer the (grit) size, the smoother the surface.”
She suggests using white primer because it seals the wood, adheres better and, as a base coat, makes the paint colors brighter. She says it’s always best to work outdoors so you won’t breathe the vapors. She usually uses acrylics (they’re more “artful”), extended with a gel medium, which keeps the paint from drying immediately. If the chair is going to be outdoors or in the sun, she suggests a final coat of polyurethane, for moisture and fade protection.