Sash Windows - journey into the unknown #6: Glazing bars

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Glad to say all the jointing is done. Now it's time to move on to the glazing bars.
This is not traditional joinery with divided lights. This is my attempt to emulate traditional joinery using modern materials and techniques to suit.



As you can see, the four windows up top and two larger windows downstairs contain 54 panes of glass. Those units would cost £50.45 each to make.
In modern double glazed windows, they make only one unit for each sash, with either internal spacer and planted on glazing bars, or a plastic moulding to emulate glazing bars, sandwiched between the glass.
In using only one unit per sash that brings the number of double glazed units down to 12. Ten of these are the same size and work out only marginally more than the small units mentioned above - £60 each, the two larger ones are about a £100 each because they need to be toughened glass due to being less than 800mm from the floor. So all in, the glass - A rated units, are coming in at about £800. This is a lot more palatable than  £2700 for 54 smaller units. There are still another 8 windows to make after this lot too, so single units are the way to go.
The units will be 4/8/4. That's 4mm glass/8mm cavity/4mm glass.
There isn't space in the depth of the window for a wider  cavity. I can't have internal spacer bars either as the cavity needs to be at least 10mm. This means the only way I can achieve the look of glazing bars is to have them on the outside of the glass.
That all seems rather long winded, I'm just trying to present the issues I'm faced with before getting to the solution.
I'll try not to harp on about the horizontal router table again but I wouldn't have been able to do this without it.
A quick change of bit and settings, and we're on to fitting the glazing bars.
I already made a bunch of glazing bars for the outside, these are triangular in section to look like the windows are puttied in.



Using a 4mm bit I've managed to stub tenon the glazing bars into the muntins and the sash.








They do not offer any structural strength to the sashes, they don't need to, as the glass will be attached to the sash and glazing bars using double sided security glazing tape.

The sash above has had all the ends dipped in preservative before gluing. The next part of this blog will be done after all the sashes are glued up, that's going to be about two weeks.



Looks like precision work, fit appears excellent!

I was wondering of you were going to go with the "micro" panes or just use full sized glass with mutton overlays.
Good info in the cost difference!
This is looking really good Renners!