How to Measure Finished Size of a Leaded Panel

How to Measure for Stained Glass

glass in stained glass lead came
How glass slots into a perimeter lead

Measuring a panel

A nooby here!! What is the best way to measure the distance between your cut size and your finish size? Im having difficulty with this. I know it may be easy, but I might be putting too much effort into it to be perfect.

Any info would be helpful.

Milly’s reply:

Hi there Liz. Lucky you, just starting out! The measuring calculations are a bit tricky until you get the hang of it…

You need to measure the aperture that your panel is going to be fitted into first. Be exact. Then you need to take 3mm from EACH side, to get a ‘fitting’ size. This is the same as glaziers cutting glass for you – they never do it exactly the same size as the hole, as there wouldn’t be room for the putty to fit it in!

You don’t need to take this 3mm off if you’re making a free-hanging panel.

I’ll assume that your outside lead came is 12mm wide. If you look at the profile of the H-shaped lead from the end, you’ll see that there is 5mm of lead flange, 2mm for the heart, and another 5mm of flange.

As your glass needs to rest alongside the heart, you need to take 5mm + 2mm (7mm) off the ‘fitting’ or ‘finish’ measurement on each side to make way for the lead.

So, if your fitting or finish size is to be 200 X 300mm, your cut size will be 186 X 286mm.

If you’re outside lead came is 10mm wide, draw a line 6mm in from each side of your Fitting Size (4mm flange + 2mm heart).
For 8mm lead, draw a line 5mm in from each side of your Fitting Size (3mm flange + 2mm heart)

I hope that’s clear. There’s also my measuring page that might help. If not, add a comment below and I’ll get back to you.


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