In Finishing

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From the left are a high-percentage methylene chloride stripper, a low-percentage methylene chloride stripper, a highly flammable stripper and a n-methyl pyrrolidone stripper.

In 1946 a fellow named William M. Barr invented a new paint stripper based on the solvent, methylene chloride. It quickly took off in the marketplace because it was a huge advance over the existing paint strippers, which were highly flammable. This advance was probably the single biggest ever made. At least, I can’t think of any others that are equivalent.

(Methylene chloride is also an exempt VOC, so it is more environmentally friendly than the flammable solvents. But this was not an issue in 1946.)

The invention of this stripper led to Barr starting a company that still exists today, WM Barr. The name you might associate most with this company is Klean-Strip.

As I reported in my May 23 blog post, the EPA intends to finalize a rule largely eliminating methylene chloride and n-methyl pyrrolidone (NMP) from paint strippers. Before becoming law this rule has to pass through the Office of Management and Budget (OMB) and be published in the Federal Register.

But in the meantime three large retail chain stores, Lowes, Home Depot and Sherwin-Williams have announced their intention to remove strippers containing these two solvents from their store shelves. Apparently, the lobbying groups that have been most up front in pressuring these companies to this action have been effective. They are Safer Chemicals Healthy Families, which claims to be a coalition of 450 organizations comprising 11 million members, the Resources Defense Council, and Mind the Store.

Before going on I want to point out how absurd I think this announcement is of Lowes, Home Depot and Sherwin-Williams. All three sell ladders. Three hundred people are killed each year from ladder falls. 164,000 go to emergency rooms. One-and-half people die each year from acute exposure to methylene chloride, most while stripping a bathtub with poor ventilation and their heads leaning down inside the tub. Methylene chloride is heavier than air, so the solvent collects in these tubs.

Eliminating methylene chloride and NMP strippers will leave the flammable strippers as the only effective alternative. There are a few others, which contain a lot of water, are very slow and won’t work on high-performance coatings.

Very old furniture and woodwork were typically finished with either shellac or lacquer, so they can still be refinished with the weaker strippers. But over the last several decades professional refinish shops have increasingly replaced these finishes with high-performance catalyzed lacquers and varnishes because of their increased durability. So, when these finishes start deteriorating and showing the need to be replaced, the only available products that will remove them may be lye, (which is destructive to the wood and joints and dangerous to work with), flammable strippers and sandpaper, which is destructive to patina and wood decoration, such as carvings, fretwork and turnings.

I have had some personal experience with the flammability issue. As I reported in the comments section of my previous methylene-chloride blog post, a number of years ago one of my furniture restoration clients hired a painter to strip the paint from the wood trim and paneling in several rooms of a very nice house. After applying the stripper to a section of one room, he flipped on a light switch, which sparked and started a fire that couldn’t be extinguished until half the house had burned down.

The flammability of these strippers is no laughing matter.

So what to do? At least for now and probably until the EPA decides to act further, methylene-chloride and NMP strippers should continue to be available at independent paint stores. These stores are not likely to bow to pressure from the lobbying groups.

– Bob Flexner

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