American Woodworker

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Winter 2013-2014

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Caution: Don't Overheat Your Cutting Board


In "Food Safe Finishes" (AW #167, Oct/Nov 2013, page 64), professional finisher Kevin Southwick recommends molten beeswax as his favorite finish for an end-grain cutting board. To apply this finish, Kevin heats the surface of the board to 175° by baking it in an oven at 375° for 10 minutes, so that the beeswax will melt upon contact with the surface and effectively seal the board. Kevin has successfully used this method to finish boards made from a number of different wood species, with thicknesses ranging from 1/4" to 2", and glued with both standard Titebond and Titebond III.

However, the story didn't mention that heating a cutting board in an oven—as with most woodworking procedures—contains an element of risk. Due to a number of variables, it's possible to overheat the board and cause damage such as warping, shrinking, cracking, failed glue joints and even charring (in extreme cases).

As oven temperatures can be inaccurate or uneven, Kevin recommends using an infrared thermometer to carefully monitor the board's surface temperature, so you don’t overheat the board by leaving it in the oven too long. (In the photo, Kevin's infrared thermometer is resting on the stovetop.) It goes without saying that using good gluing technique is a must.

An alternate method for applying a molten wax finish is to melt the wax in a double boiler on a stovetop or hot plate and then pour it onto the wood. This can be done relatively safely, according to Kevin, as long as it's understood that there's a real and dangerous risk of starting a fire. The molten wax can be ignited by a gas stovetop's open flame or by contact with the intense heat of an electric burner element. Kevin also warns that inadvertently splashing molten wax on your skin can cause severe burns.

A third alternative, heating the surface of the board with a heat gun, is a bad idea, Kevin says, for two reasons. First, you can easily overheat the board due to the localized, extremely high heat from the gun. Second, you can just as easily ignite the molten wax.

In conclusion, Kevin says, "I recommend the oven method because heating a cutting board in an oven risks only the board. There's no risk of a devastating fire, as there is with the double boiler method. The oven method works better, too, as the wax is distributed deeply, quickly, and evenly in one application."

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