In article ,
Harry Bloomfield writes:
jj has brought this to us :
Noticed that there's a new way of de-fogging double glazing without replacing
the glass. According to the details ;

Two holes are drilled, top and bottom, in the glass. Cleaning and demisting
fluid is injected into the hole and afterwards a one-way valve fitted.

I posted a method in this ng which I had come across quite some time
ago. Like your method, it involved drilling holes in two opposite
corners, but working on the assumption that the dg was just suffering
condensation from moisture leaking in - I would guess that would be the
usual case anyway.

You drill holes in two opposite corners, a good fit for plastic tube as
used for a fish tank air pump, then use a fish tank pump to circulate
air in and back out of the dg. The dg panel has to be warm and the idea
is to condense the moisture somewhere along the loop of tube and be
able to drain the accumulated water.

A coil of the pipe could be made to pass through some iced water or be
made to pass through a fridge, to act as a condenser. Once moisture
stops condensing, the panel is dry, but it can take 24 hours of pumping
to achieve it.

If the pump only has one port to which a pipe can be attached, then put
the pump in a gaffa tape sealed biscuit tin and make a second port, so
it draws its air in via the botched inlet port.

Once it's dry, you remove the air inlet pipe, with the pump running,
then quickly seal it with silicon, so it is drawn due to vacuum, squirt
a good dollop around the outlet pipe and pull that out as the silicon
is pushed into the hole to seal that end.

By the time a unit is showing condensation, it has both sprung a
leak, and the dessicant around the edge is all used up. I don't
know how long just drying the air in it is likely to last, but
I suspect not long.

If you removed the unit, what might buy you some extra mileage
is to try drying out the dessicant -- I don't know if it will dry
with any moderate heat, but you could see if application of a
hair drier drives off any moisture from it. OTOH, it may not be
realistically dryable in place (or even at all). Secondly, you
could reseal around the edge with an additional strip of
aluminium tape, hoping it will block off the leak. Finally,
before refitting, check inside the frame to make sure water
isn't pooling in there. A common cause of failures is that
water can't drain out of the frame, resulting in the unit
sitting in a puddle. This evetually damages the seal,
particularly if it ever freezes. The unit should be sitting
on spacers with channels underneath for the water to drain
away.

The second option if you have taken the unit out is to take
it round to a glazier who can take it apart, clean up the glass
(condensation eventually leaves marks between the panes),
and reassemble with new seals.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]