Cutting Opalescent Glass

People often find cutting opalescent glass more difficult than transparent. My observation is that many people exert too much pressure in scoring opalescent glass by listening for the creaking/scratching sound. 

Not all glass is made the same, even by the same manufacturer.  Scoring different glasses sounds different with the same pressure applied.  But no more pressure should be applied to opalescent glass than to transparent.  Only about two to three kilograms (5 to 7 pounds) of pressure is required to score opalescent glass sufficiently to create the weakness that we exploit when running the score.

If you concentrate on keeping the pressure on both types of glass the same, you will hear different things.  On transparent glass you normally hear a creaking or light scratching sound and you do not get a whiteness along the score line.  If you hear same sound on opalescent glass, and a white appearance showes that too much pressure is being applied. 

The same pressure (2-3 kilograms) on opalescent glass gives only a rumble of sound - no creaking or scratching is heard.  You can test this 

• Place a piece of glass on kitchen scales. 
• Zero the scales with the transparent glass on it and 
• Score without touching the glass with your other hand. 
• Note the pressure you used.  
• Zero the scales with a piece of opalescent glass on it. 
• Score to the same pressure as on the transparent glass by looking at the readout on the scales.

Just as excessive pressure on transparent glass leads to erratic breaking of the glass, so it does on opalescent glass.  You may need some practice to stop listening for a sound and begin to feel the pressure you are applying to the glass. Once you do apply the same pressure to opalescent as to transparent glass, your success in scoring and breaking opalescent glass will increase.

Scoring and breaking opalescent glass successfully is the same for both transparent and opalescent glass.  Use moderate pressure and don’t listen for the sound.

Feel the pressure. Ignore the sound.

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