Green is a popular term these days, used to mean any thing or process that is less damaging to our environment, and ultimately to us. In the finishing world, that entails two very different concepts: green finishes, which are those finishing materials deemed to be either personally or environmentally greener, and green finishing, which deals not with the finishes, but the finishing process.
Since either can give us a healthier environment, I’ll talk about both, beginning with green finishes. You should know, though, that the second alternative — green finishing — is a much simpler and cheaper way to go green. It allows us to continue using all the finishes we currently like and still make an impact, and quite possibly the largest impact of all.
The simple definition of a green finish is one that has a more benign chemical profile than the traditional finish it is designed to replace. What makes them green varies with whoever is labeling them as such. Like beauty, green is often in the eye of the beholder.
For instance, one company I spoke with was dedicated to reducing or eliminating formaldehyde in their formulas. Although the EPA does not restrict formaldehyde as either a VOC or a HAP, it is believed to be a sensitizer that can cause allergic reactions similar to flu symptoms in some people. Others seem unaffected by it. Nevertheless, OSHA, which is concerned not with the environment but with the personal safety of factory workers, has put restrictions on how much formaldehyde they may be exposed to. As a result, the coatings industry has been voluntarily reducing it in their formulas.
Another company formulates their coatings to eliminate anything that might cause any allergic reaction in sensitive people. To that end, they not only reduce VOCs and HAPs, but also other compounds, even inorganic ones, that could cause a reaction. Several companies, in fact, insist they make or sell products that have the least adverse effects on human health and the health of the planet: two concepts that sound good but whose meanings are clearly open to debate. Still others use the term green to mean low VOC coatings, while another group of companies use it to mean coatings made from natural materials, irrelevant of the VOC content.
Let’s look at a few common coatings and see how they stack up. I’ve listed them more or less from greenest to least green, but be warned: this is not a simple yardstick but rather a complex equation. In many cases, it is a judgment call as to which is really greener, and in some cases we are reduced to splitting hairs. The good news is that no matter what type of coating you like to use, there is probably a greener version of it.
Traditionally Green Finishes
Some coatings are, and have always been, surprisingly green. Milk paint, for example, contains no VOCs or HAPs and is made of completely natural and sustainable ingredients. Natural oils, such as pure linseed oil and pure tung oil, also fall into this category. Waxes, at least in their solid state, also qualify, since most of the ones we use are either plant waxes, like carnauba and candelilla, or insect waxes, like beeswax and shellac wax. However, most paste waxes, the ones that come in tins, contain some VOC solvent to make them softer and easier to apply.
Shellac is another natural, insect-made product that has a very favorable profile. The resin itself is not only renewable, but so harmless as to be edible. The most common solvent for it is ethanol, or grain alcohol, the same alcohol that appears in beer, wine and hard liquor. While ethanol is technically a VOC, it is a slow enough ozone generator that many contend it should be made exempt. In any case, it is relatively safe for the finisher, who at worst runs the risk of becoming inebriated from huffing too many fumes.