What is the purpose of scoring glass before breaking it?
Explanation: Scoring creates a shallow surface fracture (not a cut through the glass) that concentrates stress along the intended break line. When pressure is applied, the crack propagates along the score, producing a controlled break.
How many times should you run a glass cutter along the same score line?
Explanation: A score line should be made in a single pass with consistent pressure. Going over the same line multiple times crushes the glass edges, creates chips, and produces an uncontrollable break instead of a clean fracture.
Why must glass grinding always be done with water (wet grinding)?
Explanation: Wet grinding serves two critical functions: it suppresses airborne silica dust (which causes the chronic lung disease silicosis) and it cools the glass to prevent localized thermal stress that could cause cracking.
What is the correct grit progression when grinding and polishing a glass edge?
Explanation: Grinding progresses from coarse to fine. Coarse grit (80-120) removes material quickly and establishes the shape. Medium grit (220-400) smooths scratches left by the coarse wheel. Fine grit (600+) polishes to a finished edge. Skipping grits leaves visible scratches.
What width of copper foil is typically used for standard stained glass work?
Explanation: Standard copper foil for stained glass is 7/32 inch wide, which provides adequate overlap on both sides of standard thickness (3mm) glass. Wider foil is used for thicker glass or textured edges; narrower foil is insufficient for reliable adhesion.
What must be done to glass edges before applying copper foil?
Explanation: Copper foil adhesive bonds poorly to dirty, wet, or oily surfaces. Glass edges must be thoroughly cleaned and dried after grinding. Residual grinding slurry, fingerprint oils, or moisture will cause the foil to peel during soldering.
What is the function of flux in soldering copper foil joints?
Explanation: Flux is a chemical cleaning agent (typically oleic acid-based for stained glass) that removes copper oxide from the foil surface. Solder cannot bond to oxidized copper — it beads up and rolls off. Flux ensures a clean metal surface for proper wetting and adhesion.
What is lead came in stained glass work?
Explanation: Lead came is extruded lead strip with an H-shaped cross section (for interior joints) or U-shaped (for panel edges). Glass pieces fit into the channels on either side. Joints where came pieces meet are soldered together to create a rigid panel structure.
What is the primary advantage of copper foil technique over lead came for small, detailed work?
Explanation: Copper foil wraps directly onto the glass edge and conforms to any shape, including tight curves and small pieces. Lead came is rigid and requires wider channels, making it unsuitable for fine detail work but excellent for larger, simpler geometric designs.
What type of soldering iron tip is recommended for stained glass copper foil work?
Explanation: A broad chisel tip (typically 3/8 inch) provides even heat distribution across the copper foil seam, creating smooth, consistent solder beads. Fine tips concentrate too much heat in a small area, risking glass cracking and producing uneven joints.
What safety precaution is required when cutting glass that does not apply to most other workshop activities?
Explanation: Glass scoring and breaking produces tiny razor-sharp fragments and slivers that are difficult to see on work surfaces. These cause deep cuts easily. A dedicated cutting surface must be kept clean, and fragments must be swept (not wiped by hand) into a glass waste container.
When breaking a scored piece of glass, where should pressure be applied?
Explanation: The score line is placed face-up and even pressure is applied on both sides using running pliers or by hand. This opens the score fracture from below, propagating the crack cleanly along the scored line. Pressing on the score or uneven pressure causes the break to deviate.