Wednesday, 7 September 2016

Cutting from Cartoon

The cutting of glass directly over the cartoon without patterns is variously called trace cutting, English or European method. The advantages include a more direct process with fewer operations, making for less chance of inaccuracies.  These make this method quicker than using patterns or templates to draw or cut around. The disadvantages are that you still need to make patterns for opalescent or very dark glass, and there is no pattern to guide any grinding required.

To employ the method, use a strong contrast ink for drawing the lines of the cartoon. Draw these in the appropriate width - for copper foil (ca. 0.8mm).  This can be accomplished with a ball point pen or fine felt tip.  For lead, a thicker line (ca. 1.6mm) is required - a bullet tipped felt pen is usually appropriate, if it is not worn.

To cut, place the glass over the appropriate part of the cartoon and cut at the inside edge of the line. It is best to cut and break one line at a time.  Re-set the newly cut edge along the cutline and score the next line.  Break it and repeat the number of times required to cut out the whole shape.  Which line should be the first to be scored and broken is described here

Although the glass is normally only three millimetres thick, there is some possibility of a refraction of the light if you look from the side of the cutter.  As described elsewhere, you should be holding your cutter upright in the left to right plane and angled slightly back toward you so that you can look with your dominant eye along the barrel of the cutter and head.  This ensures you are directly above the cut line and do not have any refraction caused by the glass. 

Translucent glass may, and opalescent glass will, need a light box to assist in the scoring.  This increases the light coming through the cartoon and glass to enable a sharp image of the lines to be seen.  This means that if you intend using opalescent glass, your cartoon should be done on translucent paper to allow the maximum light through.

For black, dense and strongly opalescent glass, pattern pieces will need to be cut, as the insufficient light will pass through the glass to be able to see the cartoon accurately.

The reduction in the number of operations to guide the cutting of the glass also reduces the occasions for small errors to creep in.  It does increase the accuracy of cutting and speed of building a panel.