Glazing the sashes

This is the interface between old joinery with up to date fenstration (glazing)

I picked up the Double Glazed, after a slight delay - I've ended up with two toughened units for the price of one. On close inspection the two panes of glass aren't perfectly aligned and the edge spacer, being a flexible foam, isn't perfectly straight. I don't know what tolerances are usual so I'm not going to gripe about it. The edges are sealed with a hot melt black, slightly tacky stuff. This is uneven on the edges of the glass and compound the slight miss alignment of the two pieces. For the other windows I'll ask if they will pay a little more attention to this.

The sealed units fit in the sashes, resting on 5mm deep bridge packers to maintain ventilation around all the edges This should prevent any moisture from attacking the edge sealant.

The packers I bought are 24mm, the rebate is 28mm so I cut little tabs in edges so the packers will sit in the middle.

I'd ordered the units 10mm under the sash rebate sizes. The sashes are about +/- 0.5mm and the glazing (due to the misalignment and edge seal build up) are about up to + 1.5. So I had to sand down some of the packers to get neat tight fit without distorting the timber of the sash.

Next the adhesive backed EPDM seals are fitted.

The bottom seals extend horizontally and the side pieces end butt up to them.

After tinkering with all packers I was happy to screw the beading/clamp on.

Note: I had counter bored the holes a few mm to much, the head sank a bit more than I expected.

I'm generally happy with the result. The glass held firmly, the seals are well compressed, it looks neat and nothing like a plastic DG window.

The only thing that bugs me is all the screw holes that need filling. It does mean I can dissemble the sashes if or when the units eventually fail. However I keep pondering if there could be a more elegant solution, possibly using the mechanical strength of the actual units ????

Last bit of glazing is to put a bead of silicone around. I choose only to do the outside, I'll wait and see if there is any need to do the inside. In the spirit of experimentation I did one with no masking, point proved, I can't gun and tool neatly without have to scrape loads off the glass and frame. The other one I spent 5 mins masking up and did a much neater job.

USE : Low modulus - Natural cure , this is flexible, and doesn't have the solvents that react badly with Sealed units and glass coatings.

The stuff I found is labeled as a frame sealant, not glazing sealant.

This pic shows the silicone with a layer of paint on it. Can also see the silicone bead doesn't fill the flat on top of the bevel.

Note: Consider adjusting the design bevel. Reducing the flat and the over-all sash thickness.

Also prior to painting I've filled the screw hole with linseed putty. I'm not sure about this but it's reccomended by the paint manufacturer so I'm trying it.