The glass is under half of it
Start with the number everybody has: soda-lime glass is about 156 pounds per cubic foot, which is 13 pounds per square foot per inch of thickness. Eighth inch glass is therefore 1.625 pounds a square foot, and an 18 by 24 panel is 3 square feet, so the glass in it weighs 4.88 pounds.
Now add what a leaded panel actually contains. The 25.6 feet of came at 0.11 pounds a foot is 2.82 pounds. Then 0.15 pounds of solder at the joints. Cement pushed under the came flanges and cleaned off, which leaves maybe 0.12 pounds a square foot, or 0.36. And seven feet of edge bar round the perimeter at a quarter pound a foot, another 1.75.
That comes to 9.96 pounds, which is 3.32 pounds a square foot — a bit over twice the glass on its own. The glass is 49 percent of the panel. Anyone planning around 1.6 pounds a square foot is planning for less than half the object.
Every one of those figures is yours, not ours
Came weight per foot is the biggest single variable after the glass and it is the one this page refuses to guess at, because came profiles differ enormously and the difference between a light interior profile and a heavy border one is not a detail. The way to get the number is to weigh a bar on a kitchen scale and divide by its length. It takes a minute and it is right for exactly the came you have.
The cement figure is the one people always overstate, because they think of what they mixed rather than what stayed. Most of a batch is cleaned off with whiting and a brush and ends up in the bin. If you want a real number, weigh a small panel before cementing and after cleaning, and divide by its area.
The frame line is per foot of perimeter and covers zinc, brass, wood or steel equally — which is to say it covers none of them, because they are nowhere near each other by weight. Weigh a length of whatever you are using.
What the support split does and does not mean
The page divides the total by the number of support points and prints the result. That is all it does. It is arithmetic on your own inputs and it is not a statement that the load divides that way in reality, because it usually does not: geometry, the stiffness of the panel, whether it is hanging or sitting, and how level the points are all shift the share around. A panel that has started to bow loads its supports very unevenly.
And it is emphatically not a verdict on anything. Whether a hook, a chain, a bar, a sash, a frame or a piece of wall will take a given number of pounds is a question about that specific hardware and that specific structure, answered by whoever made or built it. No calculator can answer it and this one does not try. What it gives you is the pounds to take to that conversation.
Reinforcement is not on this page either
Panels above a certain size get reinforcement bars, and where they go and how many there are is a structural question — it depends on the panel, the design, the came, the glass, how it is supported and what it will be exposed to. That is a judgement for an experienced fabricator, and putting a spacing rule in a calculator would be exactly the kind of confident wrong answer that gets a window broken. The weight figure here is useful input to that conversation and is not a substitute for it.
Two panels of the same design can differ a lot
Build a design in came and the same design in copper foil and the weights diverge in two directions at once. The foil build loses the came, which is the second heaviest component, and gains a great deal more solder, because the metal now runs along every seam on both faces instead of sitting in dabs at the joints. Which comes out heavier depends on the design: a panel cut into many small pieces has a lot of seam and the foil build gets heavy; a panel of few large pieces has little seam and the came build wins.
Put your own two sets of numbers into this page to see which way your design falls. The came footage comes off the came and foil calculator and the solder weight off the solder calculator, and both of them will give you the foil figures as well.
Questions people ask
How much does a stained glass panel weigh?
Considerably more than the glass in it. An 18 by 24 panel in eighth inch glass has 4.88 pounds of glass, but add 25.6 feet of came at 0.11 pounds a foot, a little solder, the cement that stays in after cleaning and an edge bar round the perimeter and it comes to 9.96 pounds — 3.32 pounds a square foot against 1.63 for the glass alone. The glass is under half the finished object.
What does lead came weigh per foot?
That depends entirely on the profile and this page states nothing about any of them, because the spread between a light interior came and a heavy border one is large enough that a general figure would be misleading. Weigh a bar on a kitchen scale and divide by its length. One minute of work gives you a number that is correct for the came actually in your panel rather than for an average of things you did not buy.
Can I use the per-point figure to choose a hanging hook?
No. The page divides the total by the number of points you entered and reports the result, and that is arithmetic on your own inputs, not a load rating and not a verdict. Real supports do not share evenly — geometry, panel stiffness and how level the points are all move the share around, and a bowed panel loads them very unevenly. Whether specific hardware or specific structure takes a given number of pounds is a question for whoever made or built it.
How much cement stays in a panel?
Much less than you mix, which is why the field is per square foot of finished panel rather than per batch. Most of a cementing batch is pushed under the flanges, brought back out and cleaned off with whiting, and ends up as sweepings. The 0.12 pounds a square foot in the field is a placeholder. The real figure comes from weighing a small panel before cementing and after cleaning it up, and dividing by the area.
Does a foiled panel weigh more or less than the same design in came?
It depends on how the design is cut up. Foil loses the came, which is the second heaviest component, but gains a lot of solder because the metal runs along every seam on both faces rather than sitting in dabs at joints. A design cut into many small pieces has a great deal of seam and the foil build gets heavy; a design of few large pieces has little seam and the came build is heavier. Run both sets of numbers here and see which way yours goes.