Stained Glass Copper Foil Calculator
Calculate copper foil tape length and rolls for Tiffany stained glass from piece count and average perimeter.
Returns total foil in feet and 36-yard roll count.
The copper foil (Tiffany) method of stained glass construction wraps each glass piece with adhesive-backed copper tape before soldering. Calculating foil usage prevents running out mid-project.
Core Formula: Total Foil Length = Sum of all piece perimeters + Overlap allowance
For each piece: Foil per piece = Perimeter of piece + Overlap (typically 0.25–0.5 inches per piece)
Estimating Perimeters by Shape: Since stained glass pieces are irregular, approximate each piece by its closest geometric shape:
| Shape | Perimeter Formula | Example (4" wide) |
|---|---|---|
| Square | 4 × side | 16 inches |
| Rectangle | 2 × (L + W) | varies |
| Triangle | a + b + c (≈ 3 × avg side) | ~12 inches |
| Circle | π × diameter | 12.6 inches |
| Irregular | measure or estimate | varies |
Average Perimeter by Piece Size: A common estimation method uses average piece size:
| Piece Category | Avg Perimeter | Description |
|---|---|---|
| Small (under 3") | 8–10 inches | Detail pieces, eyes, accents |
| Medium (3"–5") | 12–16 inches | Standard panel pieces |
| Large (5"–8") | 18–24 inches | Background, sky sections |
| Very large (8"+) | 26–36 inches | Borders, large fills |
Worked Example — 45-piece suncatcher panel:
- 10 small pieces: 10 × 9" = 90"
- 25 medium pieces: 25 × 14" = 350"
- 10 large pieces: 10 × 21" = 210"
- Subtotal: 650 inches
- Overlap (0.375" per piece × 45): 16.9"
- Waste (5%): 33.3"
- Total: 700 inches ≈ 58.3 feet
Foil Roll Sizes: Standard rolls are 36 yards (108 feet). One roll covers approximately 65–90 medium-sized pieces depending on piece dimensions and foil width.
Foil Width Selection:
- 3/16" (4.8 mm): thin glass, delicate work
- 7/32" (5.6 mm): standard for most projects
- 1/4" (6.4 mm): thick glass, wide solder lines
- 3/8" (9.5 mm): very thick glass, decorative wide lines
Match foil width to glass thickness: foil should wrap around the edge with equal overlap on both sides (about 1/16" per side minimum).
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