posted
Has anyone ever had double pane windows crack or break because of the temperature difference that paint or vinyl might have on the windows? I have a customer that had her windows painted once and she had them crack and one of the windows, she said it kind of exploded out to the parking lot, lucky no one got hurt!
-------------------- Steve Eisenreich Dezine Signs PO BOX 6052 Stn Forces Cold Lake, Alberta T9M 2C5 Posts: 774 | From: Cold Lake | Registered: Mar 2000
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posted
Are you talking about windows on a vehicle? If so the paint was not the problems just the heat with no ventilation. On a double pane plate glass for windows, the space in the middle is sealed under a vaccuum, it would be a little hard to cause excessive internal pressure. There may have been some other defect or event.
posted
This was very early in my window painting business in Sacramento.
It was a really hot afternoon (110) we were finishing up some windows with a lot of copy...I had noticed two of the windows had a couple of beebee holes in them.
Beebee holes will make glass unstable.
Apparently, glass has a certain tension, if it has a hole or crack it can cause that tension to become unstable (well, this is how I understand it anyway)
Paint on glass contracts and expands with heat and cold, more so if it is black paint...and when you add the factor of the now unstable glass and you may end up with breakage.
That's what happened in Sacromento. As we were finishing I heard a 'Ping, Plink" and I looked up from where I was outlining and there was this split from one corner to the other across this huge pane of glass, I backed carefully away from it and contacted the owner.
I was real lucky, he paid me anyway, altho I couldn't finish the job.
Now, I have a clause in my contract that releases me from liability if the windows should break from the paint.
And if I see any crack or beebee hole, I get them to sign the contract specifying that I am not liable for any breakage.
If her windows are new, and not cracked or have holes, (and you don't cover all of them with black paint,) she has nothing to worry about.
posted
Yes! Signs can break windows! Worst case is a South facing window painted black, right to the frame...almost GUARANTEED to burst!!!!
Glass is brittle, and expands and contract with temperature! When a window is installed, it must have a space between it and the frame. A dark painted window will expand and if it happens to reach the frame, and continues to try to expaned...it will break.
After over 34 years in this biz, and a couple of broken windows...I have learned that never have a dark color any closer than 3 inches from the edge!!!
-------------------- Si Allen #562 La Mirada, CA. USA
(714) 521-4810
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siallen@dslextreme.com
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Posts: 8831 | From: La Mirada, CA, USA | Registered: Nov 1998
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posted
Yep it's the heat that's a problem and having a chip or crack in the glass like in Adrienne's case makes it even worse.
This is where my involvement in window design/engineering gets fun, cause I get to attend test labs where they test for things like this.
Most glass at a storefront level is required by code to be Tempered glass, which as A hinted, has a surface tension to it.
This tension makes the glass tougher to break. It's designed to withstand someone bumping into it or leaning against it, but if there's enough force to brake the glass, the surface tension causes the glass to break into a bazillion tiny pieces to avoid cutting people up. If there wasnt any tension on the glass, it would break into huge sharp shards and just slice everything up into pieces.
Anyways.. like Si said, if the glass is heated up enough, it will expand to its limit and blow out.. and like A said, if there's a chip in the surface, that's just like a bomb waiting to go off.. it just needs the right trigger.
On skyscrapers we deal with the same issues regarding thermal expansion. When there is a glass window in front of a steel beam, concrete beam or even at the floor slab (all in the same general area) the glass often has a "backpan" behind it. The backpan is just a piece of sheet metal that spans the window framing and makes it so people outside the building cannot see the beams, slabs, insulation and all the ugly crap that's back there. The area between the glass and backpan is called the "shadowbox." If the shadowbox area is completely sealed up, it gets hot enough inside it from the sunshine (even on a winter day) to blow out the glass! Usually the backpan is vented and the glass is either tinted or has some kind of opacifying material or printed pattern on it to reduce the heat.
-------------------- "If I share all my wisdom I won't have any left for myself."
Mike Pipes stickerpimp.com Lake Havasu, AZ mike@stickerpimp.com
Posts: 8746 | From: Lake Havasu, AZ USA | Registered: Jun 2000
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posted
three inches seems rather excessive to me. I worked in a shop and remember going to lunch with the boss and him predicting windows to break that we saw being done by some out of town snappers.(is that an oximoron?) I learned to run a strip on quarter inch tape around the edges for a stop line when doing window transparencies and valences.We did many in prussian blue that way without breakage in the southern California sun.
-------------------- The SignShop Mendocino, California
Making the simple complicated is commonplace; making the complicated simple, awesomely simple, that's creativity. — Charles Mingus Posts: 6724 | From: Mendocino, CA. USA | Registered: Nov 1998
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posted
We do a bit of flat glass tinting, and we have application guides on what type of film you can apply to certain windows in different settings... if you apply too dark of a tint on some windows it absorbs too much heat on the inner pane of glass and with the uneven expansion it wall cause cracking, so i can see where too much dark copy on a window could cause the same thing...
-------------------- Del Badry philmdesign Sylvan Lake, Alberta Posts: 636 | From: Sylvan Lake, Alberta | Registered: Nov 1998
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posted
Thanks Si, that was pretty dumb of me wasn't it? If I had reasoned it out I coulda figured that vinyl is also a color adhering to the window and absorbing heat.
Drat! There goes my sales pitch. And my trip to the bank.
-------------------- Kathy Joiner River Road Graphics 41628 River Road Ponchatoula, La.70454
Old enough to know better...Too young to resist.
Posts: 1891 | From: Ponchatoula, LA | Registered: Nov 2000
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posted
well now in my many years of playing the feid I worked in a window building plant.
yes paint will make glass break, on double pane glass double pane glass has a gas init to help stop heat or cold transfer and some glass has a a low e coating on it witch must be installed the right way or that will case the glass to break! the manuf. even tells yes to NOT put window tint on them that would make the break.
temperd glass is glass that has been heat treated I forget the scale but if you wanted a 1/4" piece that make the glass a little thicker and in the heat treating the glass melts down and does some cemical things. making this glass very strong! when we had to change a piece of this glass in a patio door we would lay the frame down and stand on the glass while cuting it out with a knife. and i weight around 250 strong stuff
well that all i know about glass on 1 cup of coffee just got kicken so forgive my spelling this morn........lol
posted
The rule as I learned it in Sign School (L.A.T.T.) is to mask all around the window with at least 3/4 inch tape for a stop line - I like Si's rule of 3 inches much better - especially with a south facing window and black paint. I suppose it also depends on the size of window. I've never done a window where I put a large panel on like this, but I've seen some, and seen some broken ones.
Posts: 1859 | From: / | Registered: Nov 1998
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I remember talkin about this with you in chat quite awhile back.
I painted silver letters on some windows for a pub called Tuxedo Junction. They wanted me to coat out the windows with black paint afterwards and I refused to do it. (All paint on the inside)
I went the next day to pick up my check and sure enough, there was another sign co. rollin paint on the windows. They didn't want any light comin through as it irritated the customers all afternoon into evening.
The next day one of the guys from the other co. called me and mentioned 3 of the 8 windows had blown out. He explained that they knew it would backfire but he was gonna pay somebody to do it...so he was the guy who got the cash. Since they warned him ahead of time and got him to sign a disclaimer, they could not be held responsible for the damage...and it was a mess!
posted
We used to stripe panels, on the inside and letter copy on the outside. Sometimes these stripes would carryover several panes. We would always leave a gap with a 1/4" Fine Line tape at each edge. I never had one break on me, but a fellow signman I know had a black panel at a car dealership crash shortly after he did the job. I don't know what condition it was in, but it was a "tall" piece of glass.
-------------------- Rich Stebbing RichSigns Rohnert Park CA 707-795-5588 Posts: 755 | From: Rohnert Park, CA | Registered: Nov 1998
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