Stained Glass Zinc Came Calculator
Calculate zinc came length for a stained glass panel from perimeter and line count.
Returns H-channel, U-channel border, and estimated solder needed.
What is zinc came?
Came (pronounced “kaim”) is the metal channel that holds pieces of glass together in a stained glass panel. Zinc came is a rigid, strong alternative to traditional lead came. It is commonly used for the outer border of a panel because it provides structural rigidity, and sometimes for straight interior lines.
Zinc came vs. lead came:
| Property | Zinc Came | Lead Came |
|---|---|---|
| Rigidity | Very rigid | Flexible |
| Soldering | Requires flux for zinc | Easy to solder |
| Weight | Lighter | Heavier |
| Typical use | Borders, straight lines | Curves, all interior |
| Profile sizes | 1/4", 3/8", 1/2" | 1/8" to 1/2" |
| Cost per foot | $1.50–$3.00 | $0.75–$1.50 |
Came length calculation:
For a stained glass panel, you need:
- Border came (zinc): The perimeter of the panel
- Interior came (lead or zinc): All the lines between glass pieces
Border came = 2 × (Panel width + Panel height) + 6" waste
Interior came = Sum of all interior cut line lengths + 10% waste
Estimating interior lines:
If you know the number of glass pieces but not the exact line lengths, a rough estimate is:
Interior came (inches) ≈ Number of pieces × Average piece perimeter × 0.5
The 0.5 factor accounts for shared edges (each interior line borders two pieces).
For a simpler rule of thumb:
- Simple geometric designs: ~4 inches of interior came per glass piece
- Moderate complexity: ~6 inches per piece
- Complex designs (many small pieces): ~8 inches per piece
Worked example:
A 24" × 18" panel with 35 glass pieces (moderate complexity):
- Border (zinc): 2 × (24 + 18) + 6 = 90 inches (7.5 feet)
- Interior came: 35 × 6 = 210 inches (17.5 feet)
- Interior with 10% waste: 210 × 1.10 = 231 inches (19.3 feet)
- Zinc came comes in 6-foot strips. Border needs: 90 ÷ 72 = 2 strips (with cutting waste)
Profile selection:
- 1/4" U-channel: Thin border, delicate look
- 3/8" U-channel: Standard border, good balance of strength and appearance
- 1/2" U-channel: Heavy panels, extra strength
- The “U” channel is for borders (one side exposed). “H” channel is for interior lines (glass on both sides).
Zinc came preparation:
Zinc must be cleaned with flux before soldering — unlike lead, zinc oxidizes and solder will not adhere to a dirty surface. Use oleic acid flux or a zinc-specific flux. File or sand the zinc at each solder joint for best adhesion.
Structural note: For panels over 4 square feet, add zinc support bars across the back every 12–18 inches to prevent sagging. Solder the support bars to the interior came joints.