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Splitting open the sealed unit...

   

Splitting open the sealed unit..stage 2

   

Refurbish the spacer bar frame...

   

Re-assemble and re-seal the unit...

   

Re-fit the sealed unit...


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

           

Misted Sealed Units

My DIY Repair of Misted Double Glazing Units

 

STEP 5 - Thoroughly clean, recheck and re-clean the glass panes....

 

Now to re-assemble sealed unit - this stage should be done in an area where there is little dust floating around. If you try this outdoors on a breezy day for example you'll be surprised at how many bits and pieces end blowing onto your scrupulously cleaned glass!

 

Take your bottom pane of glass and lay it on the workbench with the face of the pane which will be the inside face of the sealed unit upwards. Thoroughly check how clean this face is - you will not get another chance to remove any slight smears you might have left behind. If necessary lift the pane and hold it to the light to check how clean it really is.

 

I used a bought window cleaning liquid and paper kitchen roll to clean the glass. Whichever way you do it, make sure the glass is clean before you re-seal the unit!

Reassembly of sealed double glazing unit

...place the bottom pane on the bench and make sure it is thoroughly clean..

Reassembly of sealed double glazing unit - spacer frame

...position the refurbished spacer frame centrally....

Reassembly of sealed double glazing unit - top pane

...finally position the clean top pane on the frame....

Place and position the refurbished spacer frame on the glass pane - make sure it is positioned centrally with an equal distance all around the outside edge. Make sure the spacer bars are straight and not bowed.

 

 

Take the top glass pane and thoroughly check how clean its inside face is, as before hold the glass up to the light to check for smears. Make sure it is clean before placing the glass pane onto the spacer frame. Then check again how clean the glass actually is, you will find this easier if both sides of the top pane are clean.

 

You will not get another chance to check how clean the glass is......

Re-assembled sealed double glazing unit

...make sure the top pane is properly aligned with the lower pane..

Re-assembled sealed double glazing unit

...check that the edge gap to the spacer frame is the same all around the unit.....

 

STEP 6 - Re-seal the double glazing unit....

 

It is very helpful at this stage if the glass overhangs the workbench support - it is easier to work and clean-up the sealing if both top and bottom edges are free. You will also need good working room around the workbench

 

I used a good quality silicone glazing sealant which can be applied using a standard hand-operated sealant gun. Don't skimp on cost here - the quality of the silicone sealant will dictate to a large extent the durability of your repair. You want it to bond well the the glass surfaces and to last.

 

You will fill the outer gap between the panes and the aluminium spacer, so cut the sealant tube nozzle to open out a fairly generous hole consistent with the distance between the panes (the spacer size). I also cut a simple "smoothing" tool from a sheet of thin plastic card I had. The tool has a rounded front edge which I used to run along the filled gap to press the sealant into the gap and remove excess silicone - see the images.

 

Re-sealing double glazing unit

...start at a corner and fill the gap with silicone sealant..

Re-sealing double glazing unit manually

...keep a steady flow and reverse to the next corner....

Re-sealing double glazing unit

...run the smoothing tool along the gap to remove excess....

Start at a corner - I worked on one edge at a time. Run the gun along the edge filling the gap with silicone so that the sealant comes out roughly to the edge of the glass. Make sure you don't leave big air gaps - so keep a steady flow and work in reverse along the edge. Stop at the next corner.

 

 

Go back to the start of the edge you've just filled and slowly and carefully run your smoothing tool along the gap; this will squeeze the sealant and remove any air bubbles and fill gaps that you might have left. It will also ensure the silicone is pressed against the glass surfaces to make for a good bond and it will remove excess sealant. Use the tool to wipe of the excess. Take care however not to pressurise the silicone too much with the tool as this might move the spacer bar.

Cleaning a re-sealed double glazing unit

...clean the top and bottom surfaces..

DIY refurbished sealed double glazing unit

...repeat along all four edges to completely re-seal the unit....

DIY refurbished sealed double glazing unit - setting

...leave to sit for at least 6 hours for the silicone to set sufficiently for the unit to be handled....

Repeat the process for each of the remaining edges. Pay particular attention to the sealing at the corners - make sure they are properly filled and that any air gaps are filled. Visually check the contact between silicone and the glass - look for any thin areas or gaps - if you've filled the gap properly and used the smoothing tool the seal should be good all the way around.

 

Now you need to wait - the unit should be left undisturbed for around six hours to let the silicone set sufficiently to allow the unit to be handled. You can see why this job is best done on a dry day with long enough daylight - it isn't easy in the winter!

 

I have been able to handle some units after about 4 hours - but it depends on your silicone sealant's setting times. It is best to err on the safe side however and leave it well alone for longer - if you handle the unit and move one of the panes out of position then it is likely that the seal will be destroyed and you will need to split the unit, clean it up and re-seal!

 

 

Next page - for step 7, re-fitting the sealed unit to the window frame......

 

 

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