Scoring Glass

Have you ever had a bad break (with glass cutting)? Well I have; and to prevent most bad breaks, the glass must be scored properly.

Hold the cutter in your favored (tool) hand and place the cutter wheel on the glass about 1/8" (3mm) in from the edge closest to you. Now, place the thumb of your other (guide) hand behind the cutter head to prevent it from rolling back off the glass edge. Apply a firm, constant pressure straight down onto the cutter with your tool hand and push it away from you, all the way across the surface of the glass, with your guide hand.

For practice in scoring and breaking, use standard clear glass. Try shorter length scores at first, as they are generally easier to break out. Continue practicing until you get the feel for scoring and breaking.

After having made your first score, it is time to run the score. The break starts at one end and should run (follow) along the score line to the other side.

Breaking with Hands only: Form both hands into fists and place the glass between your thumbs and index fingers with the score line between your thumbs. Your fingers should be clenched underneath the glass with knuckles touching. Hold the glass firmly at the end of the score. Apply a quick even "snap" pressure by pulling outward, and roll your knuckles by spreading your thumbs apart.

With Breaker-grozer Pliers: Form one hand into a fist, placing the glass between your thumb and index finger and close to the score line. Position the flat jaw of the breaker-grozer pliers on the top side of the glass with the jaw 90° to the score and as close to the end of the score as possible. Hold the glass firmly in your hand and apply a quick, even pressure by first pulling outward, then snap down with the pliers.

Good Glass Cutting
Mike McDonough

Article Source: http://www.joannes-crafts.com