How to Score and Break an Outside Curve in Stained Glass

    Published: 06-16-2009
    Views: 34,615
    Stained Glass Artist Phillip McKee provides tips for scoring and breaking an outside curve on stained glass.

    Phillip McKee

    As an artist, I work in the medium of stained glass. I have always had an interest in stained glass. From early childhood I was enchanted by the Middle Ages and especially the medieval church. Seeing the beauty of the windows was always a joy to me. It was with great joy that I studied Medieval History first at Yale University and later at Harvard. I even held a research fellowship at Princeton in 1993. Even though I studied economic and diplomatic history instead of Art History, I still managed to work my artistic interests into my work at every possible opportunity.

    But after all of that education, I chose to become a firefighter. Needless to say, this was not greeted with much enthusiasm by my family. However a firefighter's work schedule gave me the free time I needed and I was able to pursue my other passion -- glass art!

    Since 9-11, stained glass has become an even greater part of my life as I went through rehabilitation for injuries suffered at the Pentagon. Glass has provided me with a creative outlet that I have sorely needed during this most difficult time in my life and in the life of our country. It has also given me a new place in life now that I am physically disabled and no longer able to continue as a firefighter.

    I am also pleased to announce the publication of my book Make It or Break It; Stained Glass For Beginners as a CD E-Book by CWS Press. It is an innovative CD-ROM that allows for page-flipping and browsing just like a book but it can also be searched like a regular electronic document. The CD also comes with a free trial version of GlassEye 2000 and over 340 patterns in GlassEye format.

    And I am now the senior Stained Glass Art Instructor for the Arlington County Adult Arts Education Program at the Fairlington Arts Center. If you live in Northern Virginia this is a wonderful way for you to be able to study stained glass under my tutelage while remaining close to home! In addition I offer private lessons in my home studio.

    But I did recently return to my academic roots. In June 2004, I exhibited several pieces as a part of the "Visions & Experiences" Exhibit at the Yale University School of Art Gallery. If you did not have a chance to visit the exhibit while it was occurring, I have created a Virtual Tour. It is an executable file which can be downloaded and viewed on your computer.

    Hello, my name is Phillip McKee of McKee Stained Glass and right now I am showing you how to score and break an outside curve. There are two types of curves in stained glass and I can demonstrate them both with this one curve. If you are cutting and keeping the glass, bound by this curve and throwing away this glass, then what you are cutting is an outside curve because the glass being thrown away is outside of the curve. The easiest way to cut and score an outside curve is using tangents. By that I mean, you first score and break this straight line, then you move on and score and break another straight line, followed by a third and a fourth. The more tangents you use, the closer your curve will be to perfect.

    You then grind off the excess glass. So, let us cut this outside curve, since we are not actually keeping these straight lines, we are grinding them to occur, you do not need to use your L-Square or ruler. However, you do need to remember before you begin to score to use an important piece of safety equipment, your safety goggles. Always wear your safety goggles before you begin scoring and breaking glass. So, we do our first score and you want to make sure you do not run off the glass like I just did, it can damage your cutting wheel. Once we have got our lines scored, we have get our running pliers and we squeeze. Place your excess glass aside, we do our second score, see if it will fit, if it will fit, we use our running pliers, since on either side it will not fit, we will use our Breaker/Grozer.

    Small pieces of glass can be thrown away, either have a trash can nearby or keep a small bucket near you and use that as your scrap glass collector. It is often a good idea to have a small bucket nearby because you can use your scrap glass later, either for other projects or in mosaics. With our final score, we have a piece that roughly approximates an outside curve. We will then be able to grind this down and turn it into a perfect curve. There is one other way to do an outside curve especially if it is a gently outside curve and by that I mean one that does not have too much of a curve to it. That is a special technique called a Pinch Break. We take our cutters, we score along the curve all the way around it. Pinch with your thumb and forefinger at the apex or highest point of the curve.

    Pinch it tightly, take your running pliers and we squeeze. If you have done it right, your curve will break in one single score. That is how we break an outside curve, next we will learn how to break an inside curve.