Insulated Windows

[Jon Wehrenberg]

FWIW on my 87 coach the glass lens over the rear camera would fog up on cold nights. Taking a shower was a sure way to add enough moisture to the air on the coach side of the glass so I would not have any visibility for hours.

So I removed it, cut a matching piece of glass, and on one glass I drew a bead of silicone RTV sealer about 1/4" diameter around the perimeter. I then heated that glass up so it was too hot to touch, and placed the second piece of glass on top of the bead, wiggling it only enough to see that it was in perfect contact with the bead around its entire perimeter.

Then I just left it alone until the silicone cured.

RTV silcone has some characteristics that I tried to use to my advantage. First, by heating it up the air between the two pieces of glass was warm, and hoepfully had very little moisture in it. When I put the second glass on the bead, whatever air was trapped would cool, and pull a very small negative pressure. Since RTV absorbs moisture during its curing process (from the humidity in the air) I was hoping whatever small amount of moisture I had trapped would be absorbed by the RTV.

It apparently worked because after I installed that home made thermopane rear camera glass I never got fogging, and I never saw evidence of any dirt or foreign matter between the two pieces of glass.

The only downside, and the reason I probably will not try the same on the front side glass is that I didn't draw a perfect silicone bead, and it looked uneven. Since the rear camera fiberglass housing obscured the sloppy bead it did not matter, but on the front glass I'll wager it would be visible and look lousy. When I get around to changing my front glass I will likely use a single thick pane of safety glass.

[flyu2there]

I just picked this up from another source, pretty much says it all, I hope

"There are four ways to repair an insulated glass coach window.
1. Remove the insulated (IG) glass panel. Separate the two panes. Remove and clean off the sealant/adhesive/spacer (a tedious,time consuming job). Wash the glass panes with R/O water rinse. Re-apply the appropriate seal. Re-assemble the glass panes to form the IG unit. Press the new IG panel through rollers to ensure a good seal and uniform thickness. Re assemble IG panel to metal frame with glazing seal.
2. Remove the IG panel. Use it as a template to have new tempered glass panes made. Re-assemble as above.
3. Remove the IG panel. Send it out to a specialized IG unit source to use as a template to mfr. a whole new IG panel. Re-assemble as above.
4. Build a new window.
IMHO, the best way is #4. That way you get a complete new for which the manufacturer will generally provide a limited warranty. There are many pitfalls that can be encountered by a small glass shop trying to repair an IG panel as in #1. Most will not attempt it. Most would order a new IG panel the, install it to your frame (#2).
BTW, the IG panel is assembled with regular atmospheric pressure inside; not a vacuum. The heat transfer and sound insulation is provided as a result of the dead air space between the dual panes. If they used an internal vacuum atmosphere all of the panels would have concave surfaces due to atmospheric pressure outside (14-15psi). Very undesirable."

[michaeldterry]

I will ask who it was if I get inquiries.

Lew - I need to replace my driver's side dual pane window. Please find out who the cheaper Florida company is and post contact info!

Thanks!

[Jon Wehrenberg]

John, Generally they are argon filled, although I believe any inert gas will work. I wanted negative pressure in my home made one to assure the silicone seal was 100%.

A slight negative pressure is not the same as a vacuum.

[flyu2there]

Well, as you may have suspected, this job is no fun! The seal appears to be windshield sealant with an aluminum backing....should I say fronting, because it is the aluminum that is visable when looking at the glass. That filling for the sandwich appeared to have several small voids that surely compromised the thing, they were only visible under bright light with all of the other stuff removed.

First you must pull out the entire window and casing, thence disassemble the frame to get at the pane. Course there are handles and trim pieces and such that also have to be removed, glued on, naturally. A lineolum knife was my weapon of choice to open up the sandwich then reverted to a razor blade to remove most of the old junk. A bath in lacquer thinner worked well followed by a wash and rinse in R/O water. I am troubled as to how to inject a gas into the sandwich, once made, without moving the seal which also serves as a reveal on the window. I think the only way is to make the sandwich with ambient air, let it bake for a day or two thence push in some dry nitrogen (that I have) with an exhaust hole opposite...maybe a basketball filler tip thence seal up the holes.....this cannot be an exact science. Looks like the only viable way to do this job is to have a glass shop get one some of that aluminum faced goop, anything else looks like it could be a real challenge. I also found "etching"....just mineral deposits, easily dispatched with the razor blade.

Right now, I do believe that this job would have been unnecessary had I pulled the window (s) prior to any leakage and simply resealed the outside of the entire sandwich with RTV. Still is a royal PITA however easier and cheaper than a window replacement or, as I am attempting to do, remaking the sandwich.

John

[flyu2there]

Before and after. Used Laurence double sided high density dessicant filled tape, blew it full of N2 and sealed with RTV. Test drove the thing in the shower, no fog, no seal creep................still a ROYAL PITA but this was done to a large window, with minimal training....Prevost side windows would be a walk in the park.

John

[flyu2there]

I just finished the 16th window that was leaking! Total cost, about 50.00!
While as I mentioned this job is no fun, it is not difficult even on the most convoluted windows. The etching was just dirt and other junk, razor blade should remove all signs.

A digital camera is helpful, but for the most part you remove the window, frame included. Thence you break down the window or separate the glass from the frame. Using a razor blade (I would not advise using Gillette Blue Blades, Double edged) you break the seal on the glass. Garner a suitable tool to cut thru the existing seal, usually metal and urethane. Separate the two glass pieces making certain that you label top/bottom, outside/inside. Clean the hell out of them, finish with ammonia. Apply double sided tape to one of the windows (the stuff with dessecant in it) and put the windows back together. Clean the inside of the windows again before you do this stage. Seal the edges with Black RTV, put a piece of ply over the top of this sandwich and let it sit for 24 hours, suitable weight helpful...I used my wifes silver chest...don't tell her!. Re assemble window, install in vehicle.

PS, I had a jar of N2 but I think most of that went into the atmosphere.....

New IG is pricey. The local yokals will do it for 60.00/hour. Takes about 8 hours for a big window, the Prevost windows, maybe two, at the most. Nobody will offer a guarantee so...what the hey, do it yourself.

Household windows, especially big ones, may not be advisable.........

John

[Gary & Peggy Stevens]

I just had my drivers / passengers side door windows, and toll windows tinted last week, with 3m window film, by a tint proffessional.

Having them tinted turned out to be a major improvement over the previous untinted windows as far as heat, glare and sunburn on the left arm and leg while driving.

For legal reasons they could not tint them quite as dark as the other side windows, but for my money it was a great investment in my driving pleasure.

Never saw anybody post information about having this done to their bus, so I thought I would be the first?

Gary S.

[BrianE]

Based on my experience with installing single pane windows in the Green Machine, I just changed out the windows on our Royale due to the same old bugaboo of internal fogging. Tom's windows are a complete window and frame replacement built by Peninsula Glass Co. http://www.peninsulaglass.com/. I took a little different approach to the Royale and replaced the glass with standard 1/4" tinted safety glass combined with a close cell seal to compensate for the difference in thickness of the dual pane windows. The tint is exactly the same as the windshield and is a big improvement in glare reduction.

I would be willing to take bets from anyone (John?) that a difference in sound level can't be detected. I guess it is possible that in extremely cold weather the dual pane setup might not fog as quickly, especially in a seated bus with 40 or so passengers.

[0533]

I had Prevost car replace (brand New) the front door movable window last June, it is now fogging again, the window is exactly one year old, definitely a flawed design, can't withstand the constant opening and closing of the door or was simply made poorly by the supplier.

PS> Thanks for reminding me, as all Prevost Car installs come with a One year warrantee. I just checked and it was installed at Prevost car Quebec last July 7, 2008. I am about to email Prevost to put them on notice.