On 11/05/2015 08:17, Chris Hogg wrote:
On Mon, 11 May 2015 07:29:36 +0100, Bod wrote:

On 11/05/2015 07:20, Jim GM4DHJ ... wrote:
I had a load of double glazing units I had to replace.....is there any DIY
ways to solve this problem without replacement ? ......


It can be done, but it is not easy to do. You can separate the panes and
dry them out and reseal them (apparently).
I've also heard of some people drilling a tiny hole in the corner of the
outer pane. It's said that this releases the condensation.
I wouldn't know how effective this is, plus there's always the danger of
cracking the glass during the drilling process.

I had one d/g window starting to mist up late last summer. Drilled two
holes through to the central gap, one each in opposite corners of the
_OUTSIDE_ pane, using a 3mm drill for glass/tiles (like this one
http://tinyurl.com/k86oy9a ) in a Dremel, light pressure and with
plenty of water sprayed on from a garden spray with the nozzle set to
give a jet rather than a spray. Condensation cleared over a week or
two, and has been OK through the winter. No change in the insulating
behaviour either.

Search Google groups for 'Misting DG window and drilling glass' in
September last year for a fuller description and result.

But if there are white streaks on the inner surface of the d/g because
the condensation problem has been there for a long time, those are due
to salts deposited on the glass and they won't clear by simply
ventilating the gap.

Agreed.