Stained Glass Patina Coverage Calculator
Calculate how much patina solution you need for stained glass projects based on solder line length and lead came type.
What patina does for stained glass:
After soldering a stained glass panel, the solder lines are bright silver. Patina is a chemical solution that changes the color of solder to copper (copper sulfate patina) or black (black patina). This dramatically improves the appearance of the finished piece, giving it a traditional, aged look that complements the glass colors.
Patina coverage formula:
Patina volume (ml) = Total solder line length (cm) × Solder bead width (cm) × Application factor
| Application Factor | Method | Coverage |
|---|---|---|
| 0.05 ml/cm | Cotton swab | Most efficient, least waste |
| 0.08 ml/cm | Small brush | Good control, moderate waste |
| 0.12 ml/cm | Sponge application | Quick coverage, more waste |
| 0.20 ml/cm | Dip/pour method | Fastest, most waste |
Solder bead width by technique:
| Technique | Typical Bead Width | Surface Area per cm |
|---|---|---|
| Copper foil (flat) | 3–4 mm | 0.3–0.4 cm² |
| Copper foil (beaded) | 5–6 mm | 0.5–0.6 cm² |
| Lead came (H-profile) | 4–6 mm | 0.4–0.6 cm² at joints only |
| Lead came (U-profile) | 3–5 mm | 0.3–0.5 cm² at joints only |
| Decorative overlay | 6–10 mm | 0.6–1.0 cm² |
Example calculation:
A 30 × 40 cm panel with copper foil technique:
- Estimated solder line length: 280 cm (interior + perimeter)
- Bead width: 5 mm (0.5 cm)
- Application method: brush (factor 0.08)
- Coverage: 280 × 0.08 = 22.4 ml of patina
- With 20% safety margin: 27 ml
Estimating solder line length:
| Panel Complexity | Lines per cm² | 30×40 cm Panel | 60×90 cm Panel |
|---|---|---|---|
| Simple (10–15 pieces) | 0.15 | ~180 cm | ~810 cm |
| Medium (20–40 pieces) | 0.25 | ~300 cm | ~1,350 cm |
| Complex (50–100 pieces) | 0.40 | ~480 cm | ~2,160 cm |
| Very complex (100+) | 0.55 | ~660 cm | ~2,970 cm |
Patina types and shelf life:
| Type | Color Result | Shelf Life | Notes |
|---|---|---|---|
| Copper sulfate | Warm copper/brown | 6–12 months | Most popular for nature themes |
| Black (selenium/tin) | Antique black | 6–12 months | Classic look, hides imperfections |
| Green (verdigris) | Green patina | 3–6 months | Decorative, less common |
Application tips:
- Clean solder lines thoroughly with flux remover before applying patina
- Apply patina while the piece is still slightly warm for faster reaction
- Work in small sections, rubbing with a cotton pad or brush
- Rinse with water immediately after achieving desired color
- Apply finishing wax or sealant to prevent patina from continuing to react
- Wear gloves — patina solutions stain skin and are mildly toxic