Double glazing bent spacer bars?

[Doug71]

One of my customers asked me to cast my eye over the double glazing in one of their windows, anybody seen anything like this before?

As you can see all of the spacer bars on the yellow panes have bent inwards, anybody know what could have caused this? I had nothing to do with making or fitting the windows so don't know if the glass is actually yellow or if it has some kind of coloured film on it. The windows have been in a few years and apart from the yellow pane problem they seem well made?

 

[RobinBHM]

It’s hard to know if that’s a duplex spacer bar or slimlite units.

if it’s slimline, then they are often made with a 4mm warm edge spacer bar that is pretty floppy - it would be easy for the hot melt to push the bar inwards.

on conventional DG units, it’s quite common for larger panes, say the long side of a door glass to get pushed inwards as the hot melt is applied.

This seems to be a modern problem ever since warm edge spacer bars started being used. They old aluminium spacers were much more rigid.

 

[Ollie78]

Yep, that is knackered, no way to fix it apart from new units. I have one in my old upvc side door like this
It probably is yellow glass on one pane I have had some made like this with ground/etched designs and stuff, though it should make no difference to this problem.
If it was a film and they glued the spacer bar to it then that would be daft.

Ollie

 

[baldkev]

May be worth recommending the customer contacts the supplier to see if they'll replace the units ( depending how old they are ) as the manufacturer may stand by their work.....

 

[ian33a]

The unit hasn't actually failed and it may continue to work fine for many years to come. It is, however, unsightly.

It isn't a common occurence, although I did see lots over the years.

It's especially common in units shaped such as this (long and narrow) and happens most commonly where there are extremes of heat. When hot, the primary and secondary seals soften while, at the same time, the glass doesn't have proper opportunities to deflect in the same way that a more squarer pane would (the blue unit being a case in point). When the temperature drops the spacer bar doesn't return fully to the original position (and we are talking fractions of a mm, but repeated hundreds of times). The result is the spacer bar sucked into the sight line of the unit over time.

Glass is generally clear. Units are coloured with films (there are hundreds of colours). The films are either stuck on or held in place with lead - which is also stuck on. If the unit was removed from the beads it would be more obvious as to how it is attached.

If the unit is still under warranty, you may get sympathy from the supplier. If it isn't and the visual appearance isn't of concern, I'd just leave them alone until they fail. If the units are on an exterior which gets direct sun, they will fail more quickly as UV will damage the, now, exposed primary seal (the black colour). If they are inside a propery and it just gets hot in there, they will probably go on for ages as they have limited capacity to soak up moisture and go cloudy.

If your customer wants to have them replaced, choose the film colour carefully. It's easy to get it wrong and it will look even more unsightly than an exposed primary seal - or change all of the yellow coloured units at the same time.

 

[Doug71]

The unit hasn't actually failed and it may continue to work fine for many years to come. It is, however, unsightly.

It isn't a common occurence, although I did see lots over the years.

It's especially common in units shaped such as this (long and narrow) and happens most commonly where there are extremes of heat. When hot, the primary and secondary seals soften while, at the same time, the glass doesn't have proper opportunities to deflect in the same way that a more squarer pane would (the blue unit being a case in point). When the temperature drops the spacer bar doesn't return fully to the original position (and we are talking fractions of a mm, but repeated hundreds of times). The result is the spacer bar sucked into the sight line of the unit over time.

Glass is generally clear. Units are coloured with films (there are hundreds of colours). The films are either stuck on or held in place with lead - which is also stuck on. If the unit was removed from the beads it would be more obvious as to how it is attached.

If the unit is still under warranty, you may get sympathy from the supplier. If it isn't and the visual appearance isn't of concern, I'd just leave them alone until they fail. If the units are on an exterior which gets direct sun, they will fail more quickly as UV will damage the, now, exposed primary seal (the black colour). If they are inside a propery and it just gets hot in there, they will probably go on for ages as they have limited capacity to soak up moisture and go cloudy.

If your customer wants to have them replaced, choose the film colour carefully. It's easy to get it wrong and it will look even more unsightly than an exposed primary seal - or change all of the yellow coloured units at the same time.

Thank you for your explanation Ian, that all makes sense.

There are 6 of the long thin yellow panes in this window and every single one has the same bent bar problem but it does seem like the seals are still working.

They are doing up the house ready to sell which is why they asked me to look at the window and my suggestion at the time was to just leave it for the next owner to change them if they want.