Stained Glass Solder Bead Width Calculator

Stained Glass Solder Bead

The solder bead is the rounded ridge of solder along a glass joint. Width and height determine appearance, strength, and solder consumption.

Standard bead widths by foil/came:

Bead height (cross-section):

• Flat bead: 0.5-1.0 mm, minimal solder, looks rough
• Standard bead: 1.5-2.5 mm, round, classic look
• High bead: 3-4 mm, heavy solder, max strength
• Pearl bead: 4-6 mm, maximal, for art pieces

Solder consumption math

A bead is a rounded cap sitting on the seam, not a rectangular ridge. Treating it as a rectangle, which is what most quick estimates do, overstates the solder by half. The cross-section of a rounded cap is about two thirds of width times height:

Volume per linear foot ≈ ⅔ × Bead width (mm) × Bead height (mm) × 305

Where 305 mm is 12 inches. Multiply by the alloy density for weight.

Solder density:

• 60/40 (Sn60/Pb40): 8.5 g/cm³
• 50/50 (Sn50/Pb50): 9.0 g/cm³
• Lead-free (Sn96.5, tin with about 3% silver): 7.4 g/cm³

Linear feet of solder line in a typical panel

For n roughly equal pieces in a panel W by H, every solder line on one face adds up to 2 × √(W × H × n) + W + H. A 12 × 12 inch panel cut into a 3 × 3 grid of nine pieces:

• 2 × √(144 × 9) + 12 + 12 = 72 + 24 = 96 inches, which is 8 feet
• Both faces: 16 feet of bead

Check it by hand if you like. Two interior lines each way at 12 inches is 48 inches, plus 48 inches of border, and you get the same 96.

Solder needed for 16 feet at a 5 × 2 mm bead in 60/40:

• Volume: ⅔ × 5 × 2 × 305 × 16 = 32,533 mm³ = 32.5 cm³
• Weight: 32.5 × 8.5 = 277 g, or 9.8 oz

That works out to 0.57 grams per centimetre of bead, which is the rate the solder weight calculator uses for a beaded seam. The two pages get there by different routes and land in the same place, which is the point of checking.

Soldering tips for clean beads:

1. Tin first: flow a thin layer of solder onto bare copper before bead
2. Iron temp: 700-750°F for 60/40, 800-850°F for lead-free
3. Move steadily: too slow = lumpy, too fast = thin/cold
4. Iron tip choice: chisel tip 3/8 in works for most foil work
5. Flux liberally: apply paste flux every 6-12 inches of run

Common bead defects:

• Lumpy: iron too cool, or moving too slowly
• Thin/voids: iron too hot, or moving too fast
• Ripples: dripping solder, iron tip dirty
• Spike points: flux dried, missed re-application
• Discolored bead: wrong solder, or oxidation from heat too long

Lead-free vs leaded

Note the two temperatures people mix up. 60/40 melts at about 370°F but you run the iron at 700-750°F, because the tip has to keep the joint above melting while heat drains away into the glass. Lead-free Sn96.5 melts around 430°F and wants an iron at 800-850°F. It beads less willingly, goes brittle if you cook it, and costs more, so use it where it earns its place: outdoor pieces and anything that will be handled by children or touch food.

Lead exposure in stained glass is real but modest compared with soldering electronics all day. Work with the window open, do not eat at the bench, and wash your hands. The bigger hazard for most people is the flux fume, which is an irritant whichever alloy you use.

Solder for specific applications:

• Standard: 60/40 leaded
• Lead came joints: 50/50, which matches the came and has a wider plastic range
• Outdoor or food contact: lead-free Sn96.5
• Antique restoration: 60/40 with a little silver, to match the old work

Pre-weigh before you start. Put the spool on a kitchen scale before the panel and again after, and write the linear feet down beside it. Three or four panels in, you will have a per-foot rate for your own bead style that beats any table on the internet, this one included.