Best way to fix/patch chipped bay window?

February 16, 2014 8:38 AM

Something knocked a divot knocked out of our big (6' x 4') bay window has, and there are a couple cracks radiating out from the chipped place. I'm guessing this is something we want to hop on pretty quick so it doesn't get worse. What's the best answer?

The divot is about the size of a quarter: (blurry pic). This is the outer pane of a doublepaned window, if that makes any difference.

What is the best way of repairing/patching this so it doesn't get worse? I see people online talking about nail polish, cesium oxide paste, superglue, resin from an auto glass store, etc. I dunno what's really the sensible thing here. Looks are not as important as durability for us.

posted by mattu to Home & Garden (8 answers total)

By chance is it an Andersen window less than 15 years old? I had something like this suddenly appear in one of my windows, and it turned out that (a) it was what's known as a thermal fracture caused by temperature differences inside and out and maybe sunshine effects, and (b) it was covered by a 15-year warranty so they replaced the whole pane.
posted by beagle at 9:00 AM on February 16, 2014

I wonder if an auto-glass repair place would be able to help you.
posted by jferg at 10:52 AM on February 16, 2014

Was that divot knocked out from an impact on the inside?

One thing that could help might be to seal the outside of the crack so that
water does not capillary into it. Water is known to help fractures in glass
spread more rapidly. It's probably not going to get worse very quickly.

If it was tempered, your glass would have already shattered. As it is,
the cracks might grow slowly if the window is abused (pushed on from
the inside or outside). Soda-lime window glass is well-annealed, and is
unlikely to have any embedded strains that will induce crack growth.

Measure the length of the cracks, accurately, and write them down.
Re-check occasionally.
posted by the Real Dan at 12:26 PM on February 16, 2014

The problem you will have, if you manage to fuse the glass and stop the cracks, is that moisture most likely has now gotten between the panes of double glazing and you'll start to see clouding all over the glass due to condensation.
posted by beagle at 2:36 PM on February 16, 2014

Response by poster: It is in fact an Andersen window. I have no idea how old. We bought the house about 4 years ago and there was no paperwork about this, so I imagine we're out of luck. But, we'll follow that up at least for a bit and see if it leads anywhere good.

It was knocked out from the outside, unless it was temperature changes like beagle said. The inside pane is unmarked.

We'll also try the auto-glass repair kit you all recommended. Thanks for the advices.
posted by mattu at 5:56 PM on February 16, 2014

The year of manufacture should be stamped on the little Andersen imprint which is in one of the corners. If it's less than 15 years, call any Andersen dealer and ask for the window doctor. Tell them you think it was thermal fracture. No paperwork is necessary.
posted by beagle at 7:26 PM on February 16, 2014

A couple of thoughts:

You can maybe find out how old the windows are by looking up permits issued for your property. In my city I can do this online, you might need to go to city hall. But anyway, that's how I found out when our windows were installed and even who did them.

There is a special glue you can put on window cracks to stop them, kind of like putting nail polish on a pantyhose run. You can get this at any hardware store, and it's not expensive.
posted by padraigin at 7:48 PM on February 16, 2014

Ancillary to your question, now that your thermopane window is cracked, the seal is broken and the gas inside has leaked out. The thermal performance of this window will be impaired. When this happens to my windows I replace them.
posted by Hobgoblin at 5:43 AM on February 17, 2014