Woodworker's Journal 2011-35-Winter, страница 68

BRUSH

CLEANER

Because there is no universal standard, some finish manufacturers, such as UGL, have created their own internal definitions as to what an environmentally sound finish is. This allows consumers to understand exactly what the company means by "green."

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 (see sidebar on page 67), 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. (See sidebar, previous page.) 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 can-delilla, 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.

Ultra Low and Zero VOC Coatings

Nitrocellulose lacquer, long the darling of furniture manufactur-

Formaldehyde in Finish

For the record, formaldehyde shows up in only one group of finishes we woodworkers use: the so-called catalyzed and pre-cat lacquers and conversion varnishes. It is not in shellac, lacquer, oil varnish, water-based lacquers, oil- or water-based polyurethane or even two-part automotive polyurethanes or polyesters.

Cabinetmakers who use catalyzed finishes are justifiably concerned about their workers and generally insist they wear protective gear when spraying these finishes. However, there is little concern about the end-user of the finished product. That's because the formaldehyde dissipates within a month. By the time it comes into your home, it is no longer offgassing formaldehyde.

It's worth noting that some interior plywood offgasses formaldehyde, depending on the type of glue used. Sealing the plywood with a film-forming finish blocks its release. Thus, while one type of finish can release formaldehyde, almost any other finish can block it.

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68 Green Finishing