As I put up a layer of foam-board insulation on my ceiling, I ran into the problem of how to cut the holes for the ceiling-light electrical boxes. As luck would have it, the boxes were the same diameter as a 12-oz. coffee can. Not long after this discovery, I had a hand-powered hole saw with which I could quickly and accurately cut the necessary holes.
With a half-round file, I cut a series of ragged notches in the rim of the can. The notches don’t have to be sharp, but they should be rough.
Once you locate the position of the electric box, trace around the rim of the can to mark the cutline. Now press down firmly on the can and twist it as you cut the insulation. The rough edges chew through the foam in no time.
If the insulation scrap sticks in the can, I use a toggle bolt to remove it. After poking a hole in the scrap, I shove the winged end of the bolt through the hole. Then I pull up on the bolt, and the scrap pops out.
J. Cramer Silkworth, Schodack Landing, NY
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