Almost every beginner makes the same handful of mistakes. Knowing them in advance saves a good deal of glass and frustration. These are the most frequent.
Cutting
- Pressing too hard. A score should be a single, even line with a light scratchy sound. Pressing hard can chip the edge and spoil the break.
- Going over a score twice. Never run the cutter over the same line again. Score once, in one stroke, and break the glass straight away.
- Trying a cut that cannot be made. Deep inside curves and thin tongues of glass tend to break. Change the pattern so the glass has a gentler shape.
- Using the wrong glass. Some glass is thicker or more textured and scores differently. Practise on offcuts of the sheet you will use.
Pattern and fitting
- Forgetting the lead. When lead came is used, the pieces need to be cut slightly inside the pattern line to leave room for the lead. Pattern shears with a double blade take out the right amount.
- Not grinding. Pieces that are only roughly shaped leave gaps and cause the panel to buckle.
- Not keeping the panel square. Check the corners as you build. A panel that starts crooked finishes crooked.
- Starting too ambitiously. A small panel teaches nearly everything a large one does, in far less time.
Soldering
- Dirty tip. Wipe the iron on a damp sponge and add a little solder to keep the tip bright.
- Too much heat. Holding the iron on one place too long can crack the glass or melt the lead.
- Skipping the flux. Without it, solder balls up and will not run.
- Using too much solder. Aim for a smooth, slightly rounded joint, not a lump.
Finishing
- Leaving out the cement. A leaded panel needs cement to stiffen it and keep out water.
- Cleaning too soon. Give the cement time to set before you polish.
What to do about it
Practise cutting on offcuts, create a small first panel, and expect it to have flaws. See the tools guide, the beginner overview and the step-by-step guides to cutting glass, grinding and copper foil, soldering and making a leaded panel.
Published 9 July 2026 · Last updated