What adhesive for glueing up rebuilt DG units

[Peter Scott]

I am about to try to rebuild a double glazing unit. I read from other threads that there is a method to demist them using a small drilled hole. However some of the my ones needing repair are now marked inside and need cleaning. I want to try slicing one pane off, cleaning the glass sheets, warming the separator strip to dry the silica gel then reglueing. Question is what glue to use. First thought is two-part resin. This should be water-proof and fill any small gaps. Are vapours given off during the curing process? Is it much and would they be likely to fog the cavity?

I'd welcome any suggestions for adhesives. I am going to try one unit to see if it's possible. If anyone's interested I'll report back though obviously misting might take some time. If it proves not to be any good I'll just have to buy new units.

I'm coming to the conclusion that DG is a con. It never pays for itself as the lifetime of the units is about half the pay-back time. OK an uncertain calculation with likely fuel price rises, I agree, but still sound enough. Unless you have huge windows the percentage saving is very small. Much better to put the money into micro generation or solar water heating assuming that you've already done the sensible stuff like loft and wall insulation.

Peter Scott

[Andrew Gabriel]

The ones I have looked like some sort of tar-like adhesive. This is then taped over with aluminium tape.

One thing the spacers and glue have to cope with is quite a large differential expansion between the inside and outside panes at the various temperature extremes.

Not as an energy saving measure -- it probably had the worst return of anything you might do, until wind turbines appeared. If you need to replace the windows anyway, then that's a different matter. The use of K glass is generally money particularly badly spent - the only way the industry managed to get that adopted was to force it to be a legal requirement.

Just about anything except wind turbines and photovoltaics.

[Steve Lupton]

Have you looked into the cost of simply replacing them? The sealed units are surprisingly cheap from a trade supplier.

I know this is uk.d-i-y but it sounds like an awful lot of work to rebuild a unit and with uncertain results.

Steve

[Peter Scott]

I know exactly what you mean. However I like a challenge. As it might be a simple job (who knows?) I wanted to give it a go. My kids always took the p**s that whenever we looked at furniture, electronics and so on I always said 'I can make that'. So its an experiment but I don't have a lot of practical experience of adhesives other than resins and PVA.

Peter Scott

[Dave Plowman (News)]

I'd imagine the stuff they use to stick in car windscreens would be ideal

- it is after all glass to metal. Available from your local car paint supplier. Stuff I got was made by 3M.

[Dave]

This sound much more than a challenge. First problem that I can see is getting one pane of glass off the unit, the next is putting it back together, at the correct thickness, though this might not be too hard due to the spacer that separates the 2 pieces of glass.

The adhesive will probably be a 2 part mix that is cured by the water content of the atmosphere. A bit like room temperature vulcanizing adhesive, but more like Thiokol (tm) Which is a synthetic rubber, or was when I first used it. Their site does not mention it now. Google thiokol and click on the link to viton and you may be close to what it is. Failing that, find your local sealant store or the local double glazing manufacturer and ask them what they use. Good luck with the project, but I think it may end in tears though.

Dave

[Dave]

But with a DG panel, all you are doing is sealing the gap that is formed by the 2 pieces of glass and the aluminium divider. It is breaking this seal that I find will be hard to do. Short of a router type cutter that will leave the glass intact, I can't see how the OP can do this job. I'm hopeless at ASCII art so I will try and explain. The two pieces of glass are separated by an aluminium U shaped spacer that is not bonded to the glass. The spacer is set towards the middle of the glass by a few mm. The gap that remains, after drying the air gap out, is sealed by filling the gap formed by the 2 pieces of glass and the dividing U shaped spacer. At least, mine were.

Dave

[pjlusenet]

I wondered about doing something similar. My idea was to remove the DG panel and drill a hole in the aluminium strip that joins the panes of glass. Then pour some liquid in the hole to 'wash' the panes (alcohol or vinegar?). Drain the liquid, plug the hole and re-assemble. No idea if this will work though.

[Dave]

You would end up with streaks unless you stood the window on its narrow edge and rinsed with pure water several times, even then ?

Dave

[Peter Scott]

Actually washing sounds like an idea worth a try. I imagine that alcohol might work. Alternatively B&Q are doing an excellent limescale remover called Kilrock-K at two quid. Amazing stuff! Tastes like it is formic acid (yes- tastes like! Ever bitten an ant by mistake on a bun?). Takes scale off kettles, irons, shower heads and so on in no time.

I should explain that I have a lot of windows - eighteen in all. Each has four panes. About a third of the panes need fixing. Even at quite low unit cost this will be a big saving. So this is a long-term job. I plan to do two windows at a time when decorating a room.

Anyway thanks for all the ideas and information. I think I am better equipped to start my experimenting. I'd better sound proof my workshop to keep the cussing in.

Peter Scott