Is Your Finish Food Safe
Wood finishes contain all kinds of chemicals that you would not want to put in your mouth, so you can't help but wonder: Is it safe to coat a salad bowl or a serving platter with the stuff? The answer: Any commercial finish is safe, once it has dried and cured. Here's a look at the most common concerns.
Q. Which finishes are safe for children's toys or projects that come in contact with food? A. You can use any finish that's appropriate to your project, including varnish, lacquer, shellac, and boiled linseed oil. Before putting it to use, be sure to allow for complete curing, a chemical process that takes significantly longer than drying. Some kinds of finish cure by evaporation of their solvent, and some cure by reacting with oxygen. Either way, the process continues after a film has formed on top.
Q. How long does it take various finishes to cure? A. The container label should give you general guidelines about how long to wait. For example, one salad bowl finish recommends three days of curing after the final finishing step; one brushing lacquer calls for seven days of curing before normal use. But remember that temperature, humidity, and application thickness can stretch those rules. Just to be safe, add a couple of days to any recommendation before putting the finished item to use.
Q. How about so-called salad bowl finishes? Are they any safer for use with food? A. We looked at the material safety data sheet (MSDS) for one type of salad bowl finish and found toluene--a probable cancer hazard--along with naphtha, ethyl benzene, and cobalt, all of which can damage your health with sufficient exposure. So, these products are as safe as, but no safer than, any other cured finish.
Q. Are there other substances that will protect cutting boards and butcher blocks? A. The U.S. Department of Agriculture's Forest Products Laboratory suggests melted paraffin wax. Apply as shown below.
Photographs: Marty Baldwin; Hetherington Photography