No Fish Story

Fish Tale We get some great mail here at Spectrum. Recently, Mrs. Nancy Natale, Blackwood, N.J., sent photocopies of two articles, one from "Popular Mechanics", the other from "The Family Handyman". The former begins: "It sounds crazy, and it's hard to believe until you've tried it yourself, but you can cut glass circles with scissors—if you do it underwater." The latter: "Did you know that you can use household scissors to cut glass into any shape you want? The secret? Hold the glass and shears completely underwater." Both articles speculate that it works because the water "damps vibrations" or "absorbs the shock waves," and the PM version even has step-by-step photos, suggesting that "you can use this trick to replace a broken flashlight lens, meter cover or rear-view mirror..."

Wow. This got my attention. Obviously, our entire industry had been fooled into buying expensive oil-cutters, and THE SCORE could break the scandal wide open. I immediately gave the articles to QC Supervisor Chris Cole, and asked him to test the theory. Thinking ahead, I gave copies to our glass technologist, Fritz Driesbach, as well.

In less than an hour, Chris was back in my office with the following technical report: "It works, sort of." He held in his hand three crudely cut cathedral glass circles, still wet. We examined the evidence. Most apparent, the circles hadn't been "cut," they had been grozed. Identical results, we agreed, could have been achieved with a cheap pair of grozers and no water. Superior results could have been achieved accidently by a three-year-old with a rusty Red Devil.

"It works without the water, too, but not quite as well," Chris reported,... "and it was hell on Norm's scissors."

When I told Fritz that Chris had tested the theory, his first question was: "Whose scissors did he ruin?" My question to Fritz was: "Why does it work better under water?"

"Because glass cuts better under water," he said.

"But why, Fritz?" (Investigative journalism at its best).

Ahem. We knew you'd want to know: According to Scientific American, water causes glass to crack more easily because when a water molecule enters the crack, a reaction occurs in which a silicon-oxygen bond at the crack and an oxygen-hydrogen bond in the water are cleaved, creating two hydroxyl groups attached to silicon. As a result, the length of the crack grows by the size of one bond rupture. The water reaction reduces the energy necessary to break the silicon-oxygen bonds, thus the crack grows faster.

Remember, if you try this yourself, use someone else's scissors.


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