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repair double glazing

edited 30 November -1 at 1:00AM in In my home (includes DIY) MoneySaving
87 replies 442.2K views


  • harryhoundharryhound Forumite
    2.7K Posts
    Very interesting about the water marks. I would have thought you only got permanent marks by putting cheap glass in the dishwasher.

    What is the mechanism, I've not noticed aquariums getting stained by the water ?.
    (Though I have noticed window panes marked by splashes of rendering that has not been cleaned off promptly).
  • SUCCESS! It is now 5 days since i resealed my sealed units with silicone sealant, slight mist that formed after completing the job has now all dried out, may be sealant sucked it all up, may be some remaining old desicant absorbed it, but for the last two days all sealed units are cristal clear. The whole project cost me £1.25 for a tube of sealant from LIDL's !!! You can clear water or scale markes from sealed units with a scraper/scourer/fairy liquid. As for drilling any holes, it can be done from one side, but not cleanly, but dont bother, its a waste of time. Just remove sealed unit, split the unity, reseal the edges, clean with window cleaner and refit asap.
  • kiteman 1 ,

    can you be more precise about the sealant you used , i have a leaded 1.9mtr x 900mm unit that needs condensation removing.
    yes i too am considering having a go, but investigating the absorbent stuff first. What absorbent stuff is there available ? and how much would i need to put in ?
    ive read that desiccant is used where originally i thought they were put under vacuum, the desiccant looks expensive to buy , i thought about getting some and somehow injecting it between the 2 sheets of glass but this now looks an expensive option .
    surely i could drill say a 5mm hole in the casing between the 2 sheets and then pour or inject something to absorb the condensation and then resealing with possibly clear silicone mastic etc. But what do i inject ?.
    Yes i know "i still havent found the original leak" if it has one or that its the original stuff thats broke down after i think now 10 years but im sure its worth having a try.
  • Jud, Ordinary silicon sealants, clear type, £1 to 5 per tube) the stuff the builders use, try to get the best type (unibond or polyseal) as this is supposed to last long time, similar to that are used for bath edge sealing.
    As I said before, remove the sealed unit, place on floore, split unit with stanley blade by cutting along the glass edge, clean both internal sides, try to fill the edging strip (u may hav to drill them) with some clay, carbon or silicon gel desiccant; or just before sealing place some silicon gel beads (these can be purchased from DG unit manyfacturers) cheaply from the internet) at botton of unit, refit glass with silicon sealant, just before you seal the fourth edge blow some dry hot air in the unit with hair dryer, close the sealed unit (bring the panes together on edges), the air cooling inside will form some vaccum, the remaining moisture in the unit will be absorbed by the desiccant dryer gel, seal the edges with some clear tape, fit the unit to window, place it on plastic strips tyo avoid water damaging the sealant at the bottom, for window frame strips and seals and forget about it, if u have improved the situ, u have won and it will save u ££££s. Time to do the job, 1 - 2 hrs, one to two people required; tools reqd sharp blade, chisel/mallet, sealant gun and rubber gloves. If silicon sealant is good for fish tanks, its good for sealed windows. In hot weathers u may see some mist, but the desiccants will dry most of it if u follow my instructions. What ever happens, dont panic, we r all here to support u, this is what green living is all about!! Best wishes..... Kam
  • ta very much i will wait for a warm day and have a go .
    yes i agree with you about the silicon mastic if it will hold gallons of water in a fish tank it will surely hold the double glaze seal.
    Thanks again
  • harryhoundharryhound Forumite
    2.7K Posts
    I've got a patio door to do, I think I'll give it a try!

    4 questions:
    1. "fill the edging strips (u may have to drill them)" Is this to get the desiccant inside the strips OR to let the damp air get at the desiccant OR both
    2. My local DG unit manufacturer demonstrated his machine for partially filling the edging strips with desiccant. Then to demonstrate how effective it is he poked the strip into a damp rag. It got warm suggesting some sort of chemical reaction was taking place.Any idea what he was using as desiccant?
    3. Silicon sold by Screwfix is described as Low or High "Modulus". What does this mean? Which is better if one is simply gluing a new unit into an old frame?
    Which would be better for gluing together two sheets of glass (or making an aquarium) ?
    4 I can be a messy pup; any tips for getting silicon finger prints off the outside (obviously:D) surface of the unit?

    One final thought: It would probably be better to do the job on a cool dry spring morning, with a dry easterly breeze blowing, because cold air cannot hold as much water as warm air. Warm air getting cold reaches a dew point and out comes the condensation?

  • Harry,
    1. to fill the edging strips with desiccant.
    2. Dont know why it got warm, but try it with silicon gel, also he may be using warm desiccant which has been placed in oven previously to totally dry it oput.
    3. modulus, as in density i believe, try high as this will seal and become very strong.
    4. outside prints, allow to dry and with stanley blade scrape them off or with hand just roll them off, use good window cleaner and rubber blade to wash the windows. Wear gloves, use rag to wipe access, work clean. Use plenty of desiccant and sealant, be safe, glass is sharp and heavy stuff.
    5. better to work in dry environment, or just blow cool air in the unit before finally sealing.
    Thank you all for your inputs, we r all learning from each other.
  • just had a brain wave for when i start the job,
    bottom lower left side drill 1/8 holle between glass's in the casing, insert small pipe/tube

    top upper right side drill 1/8 hole insert pipe again ,connect this to hoover and suck which will then draw the warm air thru the lower left

    place warm air unit near the lower left inlet , eg hair dryer fan heater radiater etc. this should remove moisture although might take a long time .
    when done first put silicon in lower left leave hoover sucking and THEN remove top pipe and quickly seal top right .
    What do you think ?.
    could work eh.
  • Jud, In theory yes, in practice, if u have sealed the unit well, then it should work. remember, the problems are caused by sealant between glass and edging breaking down, so this must be sealed. I tried it with hair dryer and holes, not much luck, ur better off striping the whole thing, sealing and refilling with desiccants. Feel free to copy and paste this advise to other websites.
  • For desiccants information go to the internet or below:
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