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.

Don't know how effective this method is but I'd like to give it a try. Does
anyone know where I can buy the fluid and one-way valves online (or one of
the sheds) ? Tried googling but without knowing the correct name for the
valves and fluid all I get are pages of adverts for firms who will carry out
the work for me !

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.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Sep 1, 6:50*pm, Harry Bloomfield
wrote:
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.

If youre going to make holes in glass, just drill one hole in the
outer pane and the mist wont form to begin with. Plug it with
something porous to keep out insects and draughts, eg sand/cement.


NT

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]

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.


I have successfully repaired double glazing units. Two so far, and
they've stayed clear for nearly a year. I've put the details on
www.peter-scott.org.uk/glazing.html

Peter Scott

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.


If the frames aren't wood the relevant bit is the middle section. I am
assuming that my units (from Uniglaze 2) are typical in structure

Peter Scott

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,

Just to point out... if you're drilling through the glass and it's
toughened glass (as increasingly they are nowadays), then you won't
get as far as drilling the second hole. You bypass that and go
directly to the dustpan and brush stage, followed by the yellow
pages ;-)

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

After serious thinking Andrew Gabriel wrote :
Just to point out... if you're drilling through the glass and it's
toughened glass (as increasingly they are nowadays), then you won't
get as far as drilling the second hole. You bypass that and go
directly to the dustpan and brush stage, followed by the yellow
pages ;-)

You do NOT drill the glass, you drill holes through the gap between the
panes (through the seal).

To answer the other question about a repaired panels insulation
properties, I would imagine it will be similar to when the panel was
new - why would it be any different?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
After serious thinking Andrew Gabriel wrote :
Just to point out... if you're drilling through the glass and it's
toughened glass (as increasingly they are nowadays), then you won't
get as far as drilling the second hole. You bypass that and go
directly to the dustpan and brush stage, followed by the yellow
pages ;-)

You do NOT drill the glass, you drill holes through the gap between
the panes (through the seal).

Aha! I'm glad you clarified that. I was reading that as drilling the
glass.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

"The Medway Handyman" wrote in message
om...
Harry Bloomfield wrote:
After serious thinking Andrew Gabriel wrote :
Just to point out... if you're drilling through the glass and it's
toughened glass (as increasingly they are nowadays), then you won't
get as far as drilling the second hole. You bypass that and go
directly to the dustpan and brush stage, followed by the yellow
pages ;-)

You do NOT drill the glass, you drill holes through the gap between
the panes (through the seal).

Aha! I'm glad you clarified that. I was reading that as drilling the
glass.


But what about jj's remarks in the OP, he was advocating drilling the glass
wasn't he?

--
Graham.

%Profound_observation%

On Tue, 01 Sep 2009 20:24:27 +0100, Harry Bloomfield wrote:

After serious thinking Andrew Gabriel wrote :
Just to point out... if you're drilling through the glass and it's
toughened glass (as increasingly they are nowadays), then you won't
get as far as drilling the second hole. You bypass that and go
directly to the dustpan and brush stage, followed by the yellow
pages ;-)

You do NOT drill the glass, you drill holes through the gap between the
panes (through the seal).

To answer the other question about a repaired panels insulation
properties, I would imagine it will be similar to when the panel was
new - why would it be any different?

Some double glazing units are Argon filled.

SteveW

It happens that Steve Walker formulated :
On Tue, 01 Sep 2009 20:24:27 +0100, Harry Bloomfield wrote:

After serious thinking Andrew Gabriel wrote :
Just to point out... if you're drilling through the glass and it's
toughened glass (as increasingly they are nowadays), then you won't
get as far as drilling the second hole. You bypass that and go
directly to the dustpan and brush stage, followed by the yellow
pages ;-)

You do NOT drill the glass, you drill holes through the gap between the
panes (through the seal).

To answer the other question about a repaired panels insulation
properties, I would imagine it will be similar to when the panel was
new - why would it be any different?

Some double glazing units are Argon filled.

But would this (what I would assume to be an old panel) be argon
filled. It is old and the OP is just wanting to prolong its useful life
a little longer.

The silica gel in the pump box suggestion was a good one. I think that
was a part of the method I read.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Andrew Gabriel wrote:
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,

Just to point out... if you're drilling through the glass and it's
toughened glass (as increasingly they are nowadays), then you won't
get as far as drilling the second hole. You bypass that and go
directly to the dustpan and brush stage, followed by the yellow
pages ;-)

I was just about to make that very point. Drilling any kind of glass is
precarious in the extreeme, let alone toughened.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

Harry Bloomfield wrote:
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.

At this point, if using a box, I would put a quantity of oven dried
silica gel in it.

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.

A lot of civil aircraft are kept clear by inserting a tube into the
lower edge whose other end is connected to a silica gel container, but
that would be difficult to do with a DG window.

Dave

Dave wrote:

A lot of civil aircraft are kept clear by inserting a tube into the
lower edge whose other end is connected to a silica gel container, but
that would be difficult to do with a DG window.


I suspect the large pressure changes experienced by an aircraft help
there - every time you go up a lot of the air gets forced out, only to
be replaced on the way back down.

Andy

Dave has brought this to us :
A lot of civil aircraft are kept clear by inserting a tube into the lower
edge whose other end is connected to a silica gel container, but that would
be difficult to do with a DG window.

Not to mention the cost of hiring an aircraft to take the panel up :-)

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
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.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

The drying bit looks decidedly heroic!.
On my misty DG unit, I'm thinking it's easier just to percolate
through a bag of silica gel dessicant.

jj wrote:
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.
Don't know how effective this method is but I'd like to give it a
try. Does anyone know where I can buy the fluid and one-way valves
online (or one of the sheds) ? Tried googling but without knowing the
correct name for the valves and fluid all I get are pages of adverts
for firms who will carry out the work for me !

Surely it'd be better just to spend a few quid and get a new pane of glass
and have a proper functioning DG unit again? If you want to save a few quid,
remove the old one and fit the new one yourself. I would think these repairs
leave the pane of glass with a similar insulating factor as a single glazed
window.

Davey coughed up some electrons that declared:


Surely it'd be better just to spend a few quid and get a new pane of glass
and have a proper functioning DG unit again? If you want to save a few
quid, remove the old one and fit the new one yourself. I would think these
repairs leave the pane of glass with a similar insulating factor as a
single glazed window.

Well, a DG panel is anywhere from 70-100 quid per m2 (depending on glass) so
I suppose if the panel is large or times are tight, a repair might be worth
the effort.

But if possible to replace I would agree at least the effort of refitting
will be good for a decade or 3.

Cheers

Tim

On 1 Sep, 20:13, Tim S wrote:

Well, a DG panel is anywhere from 70-100 quid per m2 (depending on glass) so
I suppose if the panel is large or times are tight, a repair might be worth
the effort.


How much? That made me look up the invoice for the only units I've
ever bought on their own, which were £59/m2 for 4:6:4 and £77/m2 for 6
(lam):6:4(toughened) - but that was with a krypton fill to get to
1.4U. An argon fill would have been £39/m2 and £47/m2. That's with
top spec glass to get the U value. Figures inc VAT.

Bolted coughed up some electrons that declared:

On 1 Sep, 20:13, Tim S wrote:

Well, a DG panel is anywhere from 70-100 quid per m2 (depending on glass)
so I suppose if the panel is large or times are tight, a repair might be
worth the effort.


How much? That made me look up the invoice for the only units I've
ever bought on their own, which were £59/m2 for 4:6:4 and £77/m2 for 6
(lam):6:4(toughened) - but that was with a krypton fill to get to
1.4U. An argon fill would have been £39/m2 and £47/m2. That's with
top spec glass to get the U value. Figures inc VAT.

2 glaziers in the SE quoted very similar figures.

Whereabouts are you?

On 1 Sep, 22:55, Tim S wrote:
Bolted coughed up some electrons that declared:

On 1 Sep, 20:13, Tim S wrote:

Well, a DG panel is anywhere from 70-100 quid per m2 (depending on glass)
so I suppose if the panel is large or times are tight, a repair might be
worth the effort.

How much? *That made me look up the invoice for the only units I've
ever bought on their own, which were £59/m2 for 4:6:4 and £77/m2 for 6
(lam):6:4(toughened) - *but that was with a krypton fill to get to
1.4U. *An argon fill would have been £39/m2 and £47/m2. *That's with
top spec glass to get the U value. *Figures inc VAT.

2 glaziers in the SE quoted very similar figures.

Whereabouts are you?

SE London - try Olympic Glass next time (they are on Sheppey).

Davey wrote:
Surely it'd be better just to spend a few quid and get a new pane of glass
and have a proper functioning DG unit again? If you want to save a few quid,
remove the old one and fit the new one yourself. I would think these repairs
leave the pane of glass with a similar insulating factor as a single glazed
window.


We've just misted glass planes replaced in a couple of our 15 yr
windows. The ease at which the original glass was lifted out - from the
outside - and disparaging comments on security by the installer after
the job was finished, made me wish that there and then we stumped up for
the replacement of the whole aluminium frame and not just the glass!

Oh well :-|

(BTW if some of ye feel like some burglary in me gaff, beware of the dog...)

--
Adrian C

In article ,
Adrian C writes:
Davey wrote:
Surely it'd be better just to spend a few quid and get a new pane of glass
and have a proper functioning DG unit again? If you want to save a few quid,
remove the old one and fit the new one yourself. I would think these repairs
leave the pane of glass with a similar insulating factor as a single glazed
window.


We've just misted glass planes replaced in a couple of our 15 yr
windows. The ease at which the original glass was lifted out - from the
outside - and disparaging comments on security by the installer after
the job was finished, made me wish that there and then we stumped up for
the replacement of the whole aluminium frame and not just the glass!

Not sure about aluminium, but with PVC, window tape is used nowadays
instead of the internal strips. Whilst you can still lever out the
external beading, you can't lift the glass out afterwards.

There was a period of having the beading internal, but that makes the
frames much more bulbus and less glass to let light through,
particularly on openers. Some people still ask for this, but it's
really a hangover from the past.

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

Andrew Gabriel coughed up some electrons that declared:

In article ,
Adrian C writes:
Davey wrote:
Surely it'd be better just to spend a few quid and get a new pane of
glass and have a proper functioning DG unit again? If you want to save a
few quid, remove the old one and fit the new one yourself. I would think
these repairs leave the pane of glass with a similar insulating factor
as a single glazed window.


We've just misted glass planes replaced in a couple of our 15 yr
windows. The ease at which the original glass was lifted out - from the
outside - and disparaging comments on security by the installer after
the job was finished, made me wish that there and then we stumped up for
the replacement of the whole aluminium frame and not just the glass!

Not sure about aluminium, but with PVC, window tape is used nowadays
instead of the internal strips. Whilst you can still lever out the
external beading, you can't lift the glass out afterwards.

There was a period of having the beading internal, but that makes the
frames much more bulbus and less glass to let light through,
particularly on openers. Some people still ask for this, but it's
really a hangover from the past.


My beading came internal as standard - I'd though it was normal...

"Adrian C" wrote in message
...


(BTW if some of ye feel like some burglary in me gaff, beware of the
dog...)

Its OK they always carry a can for the dog.

Adrian C wrote:

(BTW if some of ye feel like some burglary in me gaff, beware of the
dog...)

Reminds me of an old joke...

Kid: Want us to look after yer car for a fiver mate?
Man: It's ok, my dog's in it and he'd make a mess of anyone who touches it!
Kid: Can it put out fires?

"Any original filling has been lost and replaced by air many
times over long before the condensation became visible."

I am looking at making a set of patio doors - but I don't like the idea of
sealed DG units that will probably or definitely go off in 5 years time or
even less.. didn't windows used to last for a century?

I was thinking of installing two panes of toughened glass to each door as
with a DG unit, but with the panes not sealed. The interior facing pane on
its own frame with spacer fixings. This would be to give ventilation between
the panes to reduce condensation, but be able to close them up tight when it
gets really cold during the winter. Are there reasons why this wouldn't work?


url:http://myreader.co.uk/msg/1391145585.aspx

On Sep 23, 5:31*pm, "Hugo wrote:
"Any original filling has been lost and replaced by air many
times over long before the condensation became visible."

I am looking at making a set of patio doors - but I don't like the idea of
sealed DG units that will probably or definitely go off in 5 years time or
even less.. didn't windows used to last for a century?

I was thinking of installing two panes of toughened glass to each door as
with a DG unit, but with the panes not sealed. The interior facing pane on
its own frame with spacer fixings. This would be to give ventilation between
the panes to reduce condensation, but be able to close them up tight when it
gets really cold during the winter. Are there reasons why this wouldn't work?

url:http://myreader.co.uk/msg/1391145585.aspx


air exchange would result in condensation. That would rot a timber
frame, if used, and require regular wiping.

The way to solve this is to vent the space to the outside rather than
inside, then no condensation occurs. Maybe use a plug of 9:1 sand and
cement to keep insects etc out


NT

In article ,
"Hugo writes:
"Any original filling has been lost and replaced by air many
times over long before the condensation became visible."

That's after the seal has failed (to put it back in context).

I am looking at making a set of patio doors - but I don't like the idea of
sealed DG units that will probably or definitely go off in 5 years time or
even less.. didn't windows used to last for a century?

When properly manufactured and properly fitted, sealed units will
last for a long time. I replaced some first generation double
glazing after about 25 years, and only one out of probably some
30 panes failed in that time, and that was due to someone having
removed the unit at some point in the past and damaged it in doing
so. The patio windows in my current house are 20 years old, with
no sign of failing seals.

I was thinking of installing two panes of toughened glass to each door as
with a DG unit, but with the panes not sealed. The interior facing pane on
its own frame with spacer fixings. This would be to give ventilation between
the panes to reduce condensation, but be able to close them up tight when it
gets really cold during the winter. Are there reasons why this wouldn't work?

You will always get condensation at some point if the unit isn't
sealed. The temperature differential, temperature variations, and
time to diffuse replacement air in just won't keep the inside dry.

If you are designing your own doors to take sealed units, it's
vital to understand the environment in which the units must be
fitted, as it's incorrect fitting that results in most sealed
unit failures over time. The main cause of failure is that the
unit ends up sitting in a puddle in the bottom of the frame.
In plastic frames, the unit should sit on a number of plastic
spacers along the bottom, which hold it above the drainage
channels in the frame. The drainage channels must actually
work and drain the water away from the bottom channels. The
rubber seals against the glass are not designed to be completely
waterproof (they're designed for speedy fit by less skilled
fitters instead) and water which gets through must drain out.

I don't know how it's supposed to work with timber frames.

With first generation metal frames, the outer glass was sealed
to the frame to prevent any water ingress, and where this was
done properly, those units at now over 30 years old are still
fine. The snag is that fitting those units was a much more
skilled job than fitting today's PVC units is, which made them
both relatively more expensive and/or more prone to being
fitted wrongly.

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

In message , Andrew Gabriel
writes
If you are designing your own doors to take sealed units, it's
vital to understand the environment in which the units must be
fitted, as it's incorrect fitting that results in most sealed
unit failures over time. The main cause of failure is that the
unit ends up sitting in a puddle in the bottom of the frame.
In plastic frames, the unit should sit on a number of plastic
spacers along the bottom, which hold it above the drainage
channels in the frame. The drainage channels must actually
work and drain the water away from the bottom channels. The
rubber seals against the glass are not designed to be completely
waterproof (they're designed for speedy fit by less skilled
fitters instead) and water which gets through must drain out.

I don't know how it's supposed to work with timber frames.

I have just done some after criticising the builder's efforts. The
rebate is suited to the current dg width plus two lots of 3mm thick
arboseal. The glass is stood on plastic spacers as you describe. The
bottom bead is *L* shaped and stands on thicker rigid plastic spacers
thus leaving a space for water to escape and the *L* forming a weather
drip.

With first generation metal frames, the outer glass was sealed
to the frame to prevent any water ingress, and where this was
done properly, those units at now over 30 years old are still
fine. The snag is that fitting those units was a much more
skilled job than fitting today's PVC units is, which made them
both relatively more expensive and/or more prone to being
fitted wrongly.

regards


--
Tim Lamb

On Sep 1, 6:08*pm, "jj" wrote:
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.

Don't know how effective this method is but I'd like to give it a try. Does
anyone know where I can buy the fluid and one-way valves online (or one of
the sheds) ? Tried googling but without knowing the correct name for the
valves and fluid all I get are pages of adverts for firms who will carry out
the work for me !

probably alcohol with a crazy markup


NT