Copper Foil Stained Glass Pattern

One reference square, three real offsets

Read the heart width before the visible solder line

In this workshop, the heart is the physical separation assigned between neighboring glass pieces. The 0.8 mm copper foil setting is a working allowance, not the width of the visible solder bead or the nominal width printed on a foil roll. Each glass outline moves inward by half that allowance: 0.4 mm. Two adjacent inset edges therefore leave a combined 0.8 mm gap across their shared centerline. Changing the preview stroke from thin to thick does not change that physical distance.

A numbered centerline cartoon and an inset cutting pattern serve different purposes. The centerline describes where the piece boundaries meet in the intended assembly. The inset pattern describes the glass blank. Keep both beside the project, and label which one you are tracing. Cutting every piece to its full centerline outline leaves the allowance unaccounted for; adding foil and solder afterward does not make that extra material disappear.

Recalculate the 100 mm square

Start with a square whose four centerline sides are 100 mm. Moving its left and right edges inward by 0.4 mm gives 100 − 0.4 − 0.4 = 99.2 mm. Its top and bottom move by the same amount. The net glass area is therefore 99.2 × 99.2 = 9840.64 mm², or 98.4064 cm². This is an offset of the polygon; reducing only the drawn stroke width would leave the geometry at 100 mm.

For ten such squares, the net area is 984.064 cm². With a 25% waste allowance, the purchasing estimate becomes 1230.08 cm². If five squares use each of two colors, each color contributes 492.032 cm² net and 615.04 cm² with waste. The table in the workshop calculates those quantities from the actual inset polygons. Width and height are reported separately because the enclosing rectangle of a nonrectangular piece has a different area from the piece itself.

Match foil width to your measured glass

A 7/32 inch foil roll is 5.55625 mm wide, while a 1/4 inch roll is 6.35 mm wide. Neither measurement is the 0.8 mm seam heart. To estimate how much foil can turn onto each face of a centered straight edge, subtract the measured glass thickness from the tape width and divide the remainder by two. For 3 mm glass, that simple estimate gives 1.278125 mm per face with 7/32 inch tape, or 1.675 mm with 1/4 inch tape.

That estimate assumes a centered wrap on a regular edge. An uneven edge, heavy texture, actual foil adhesive thickness, or a deliberately off-center wrap changes the result. Measure a real sample and compare both faces before preparing the whole panel. Tape width is a choice about coverage and appearance; it is not an instruction to replace the physical seam setting with 5.56 or 6.35 mm. The cutting inspector keeps heart and inset separate to make that distinction visible.

Inspect small tips before preparing stickers

Set the real panel dimensions first. A 10 mm strip that is acceptable to review at one scale will shrink if you reduce the panel afterward. The minimum width control accepts 6–20 mm and defaults to 10 mm. It checks a physical width or interior neck, rather than approving a long thin fragment because its area looks large. Raising the threshold to 15 mm is a way to find more areas to examine, not a guarantee of break behavior.

A 270-degree inward corner is a different issue from a narrow strip. A template with a deep notch may require grinding or a new division, even after neighboring pieces are merged. Select the warning to locate the number, inspect its neighbors, and keep any unresolved advice with the cutting plan. A piece that collapses or self-intersects under the requested inset blocks the cutting export; the tool does not silently drop it from the file.

Use the appropriate free or production file

The basic inset SVG is a free single layer of physical-size closed cutting contours. The centerline SVG and DXF are also free, but describe the unshrunk boundaries. Standard tiled PDFs are free with a website footer. Use those files for a measured paper trial and a small workshop pattern. A single-page PNG is useful for reference, but its viewing size should not replace a PDF ruler or the millimetre dimensions carried by a vector file.

The compensated production pack is a separate server-authorized ZIP: closed CAD polylines with millimetre units, layers by color and piece number, a sticker-die SVG with an outer weeding box and registration holes, plus an offset verification manifest. The matching IDs let you compare a cutting contour with its table entry. This is a standard vector delivery, with no claim of official certification for a particular cutter, laser or piece of hardware.

Check a physical trial before the full batch

Print the cartoon at 100% or Actual size, with fitting disabled. Measure the 100 mm or 4 inch ruler on the paper. Then compare one printed numbered piece with the inset dimensions in the workshop inspector. Keep the same project snapshot for the cartoon, cutting file and material list so that a later color change or merge does not leave two incompatible sets of piece numbers on the bench.

For stickers, identify the registration marks and the waste outside the cutting contours before removing the weeding frame. Keep the numbered association between a loose sticker and its glass blank. Cut a representative small piece and a broad piece first, inspect their fit in the intended assembly, and adjust the real process to the glass and tools in use. Geometry is a planning aid; it cannot certify a finished solder joint or structural panel.